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ASSESSMENT OF PERFOU.MANCE AND IMPACT OF A
TWO-YEAR NATIONWIDE SCHISTOSOMIASIS
HAEMATOBIA CONTROL PROGI~MME IN
BURKINA FASO (2004 - 2005)
By
Albis Francesco Gabrielli
(PhD Candidate)
A Thesis Submitted to the School of Public llealth, University
of Ghana, in Fulfilment of the Requirement for the Award of a
Doctor of Philosophy Degree in Public Health
August, 2010
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DECLARATION
I hereby declare that this study was carried out by me and that contributions and support
received from any other person have been duly acknowledged in the thesis. I also do
declare that this thesis, either in part or whole, has not been submitted elsewhere for an
award of a degree or diploma.
Albis Francesco Gabrielli
(PhD Candidate)
Professor Michael David Wilson
(Supervisor)
Professor Fred Newton Binka
(Supervisor)
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ACKNOWLEDGEMENTS
This thesis is about control of schistosomiasis in Burkina Faso from 2003-2005. The
activities and the data cover the period during which I was working as Regional
Programme Manager for West Africa with the Schistosomiasis Control Initiative at
Imperial College, London (SCI-ICL). During this period, I spent roughly half of my life
operating from an office at Imperial College's in London and the other half at the
headquarters of the Programme National de Lutte contre la Schistosomiase et les Vers
Intestinaux (PNLSc) or the National Schistosomiasis and Soil-Transmitted Helminth
Infections Control Programme, Ministry of Health, Ouagadougou, Burkina Faso. At that
time, SCI-ICL was the main partner of the PNLSc and my responsibility was to
coordinate the provision of technical and financial support to schistosomiasis control
activities at the national level. I worked closely alongside PNLSc staff and had a
wonderful and fruitful time, which I still remember with nostalgia and has been one of
the turning points of my personal and professional life.
I am therefore very grateful to both the Schistosomiasis Control Initiative - Imperial
College London and the Bill & Melinda Gates Foundation. The two institutions
sponsored and supported the studies design, planning, implementation, data collection
and analysis, and reporting. I am especially indebted to Professor Alan Fenwick, OBE as
without his fatherly patronage this work would not have been possible. Thank. you Alan!
I am also very grateful to the national authorities of Burkina Faso, and especially to the
Ministry of Health, for permission to conduct the studies and to use this data, and for two
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great years spent working with colleagues in the country. In particular I would like to
express my gratitude to Dr Seydou Toure, the Coordinator of the National
Schistosomiasis Control Programme.
I would also like to thank my present supervisors and colleagues at WHO Dr Lorenzo
Savioli, Dr Dirk Engels, Dr Lester Chitsulo and Dr Antonio Montresor for allowing and
prompting me to complete my studies in spite of the multiple professional commitments.
Finally, I am most grateful and indebted to my PhD thesis supervisors at the University of
Ghana Professors Michael D. Wilson and Fred N. Binka for their professional guidance
during the study period.
The various forms of support given me in the course of the realization of this work by;
Professor Edwin Afari, Dr Moses K. S. Aikins, Ms Henrietta Allen, Ms Elisa Bosque-
Oliva, Dr Archie C. Clements, Mr Ruairidh Crawford, Professor Christl A. Donnelly, Mr
Cesaire Ky, Mr Alexei Mikhailov, Mr Justice Nonvignon, Mr Hamada Ouedraogo,
Professor David Ofori-Adjei, Dr Souleymane Sanou, Dr Bertrand Sellin, Mrs Elisabeth
Sellin, Mr Howard Thompson, Professor Joanne P. Webster, Mr Malachie Yaogho and
Dr Yaobi Zhang are also gratefully acknowledged. Special thanks go to Dr Artemis
Koukounari for her help and guidance with the statistical analysis.
Likewise the goodwill and cooperation of the chiefs, elders, opinion leaders and
inhabitants of communities in the intervention areas in Burkina Faso are acknowledged.
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DEDICATION
To my family
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TABLE OF CONTENT
TITLE PAGE
DECLARATION ..... ii
ACKNOWLEDGEMENT iii
DEDICATION ..... v
TABLE OF CONTENT ..... VI
LIST OF FIGURES ..... x
LIST OF TABLES ..... Xl
LIST OF APPENDICES ..... xii
LIST OF ABBREVIATIONS ..... xiii
ABSTRACT ..... xiv
CHAPTER ONE - GENERAL INTRODUCTION
1.1 Introduction ..... 1
1.2 Rationale and objectives . 4
1.2.1 General objectives . 6
1.2.2 Specific objectives . 7
CHAPTER TWO - LITERATURE REVIEW
2.1 Schistosomiasis: an introduction ..... 9
2.1.1 Transmission ..... 9
2.1.2 Clinical manifestations ..... 11
2.1.3 Pathogenesis of S. haematobium infection ..... 12
2.2 The global burden of schistosomiasis ..... 14
2.3 Epidemiology of schistosomiasis ..... 16
2.4 Control of schistosomiasis ..... 18
2.4.1 Current strategy for control.. ... 19
2.4.1.1 Preventive chemotherapy ..... 21
2.4.1.2 Praziquantel as the drug of choice for schistosomiasis
control. .... 24
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2.4.2 The assessment of performance and impact
of praziquantel-based schistosomiasis control interventions 27
2.4.2.1 Performance..... 28
2.4.2.2 Impact..... 30
2.5 Schistosomiasis in Burkina Faso..... 33
2.5.1 Epidemiology of schistosomiasis in Burkina Faso..... 33
2.5.2 Schistosomiasis control in Burkina Faso..... 36
2.5.2.1 Schistosomiasis control implemented
under the B&MGF/SCI-ICL grant..... 38
2.5.3 The structure of the health system in Burkina Faso..... 41
CHAPTER THREE - MATERIALS AND METHODS
3.1 The Study Area: Burkina Faso..... 44
3.1.1 The target population..... 47
3.2 Description of programme activities..... 48
3.2.1 Implementation units..... 49
3.2.2 Procurement and distribution of material..... 50
3.2.3 Communication strategy for social mobilization..... 51
3.2.4 Staffing and remunerations..... 52
3.2.5 Training of staff..... 53
3.2.6 Drug delivery channels..... 54
3.2.7 Administration of praziquantel..... 54
3.2.7.1 Inclusion and exclusion criteria..... 55
3.2.8 Reporting and management of adverse events..... 55
3.2.9 Data collection and managemcnt: performance indicators..... 56
3.2.10 Data collection and management: impact indicators..... 57
3.3 Assessment of Programme Performance.... 58
3.3.1 Coverage..... 58
3.3.2 Costs..... 59
3.4 Assessment of Programme Impact..... 62
3.4.1 Impact assessment using longitudinal survey..... 63
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3.4.2 Assessment of community-based interventions
using cross-sectional survey of new-enrolled ..... 64
3.4.3 Cross-sectional survey of school children for
cohort data validation (school control group) . 66
3.4.4 Calendar of baseline and follow-up activities . 66
3.4.5 Drop-outs ..... 67
3.5 Description of Methods ..... 69
3.5.1 Infection indicators ..... 69
3.5.1.1 Diagnosis of urinary schistosomiasis ..... 69
3.5.1.2 Diagnosis of parasitic infections
other than urinary schistosomiasis.. ... 69
3.5.2 Morbidity indicators.. ... 70
3.5.2.1 Haemoglobin status and prevalence of anaemia..... 70
3.5.2.2 Detection of microhaematuria..... 72
3.5.2.3 Determination of nutritional status.. ... 72
3.5.3 Data analysis.. 73
3.6 Ethical Considerations. 74
CHAPTER FOUR - RESULTS
4.1 Performance ..... 75
4.1.1 Coverage ..... 75
4.1.2 Costs ..... 79
4.2 Impact ..... 83
4.2.1 Profile of cohort and drop-out children
in the longitudinal survey... ... 83
4.2.2 Infection indicators: longitudinal survey.. ... 84
4.2.3 Infection indicators: cross-sectional survey,
first-year, 7 year-old schoolchildren.. ... 88
4.2.4 Infection indicators: cross-sectional survey,
age- and gender-matched control schoolchildren.. ... 92
4.2.5 Morbidity indicators: longitudinal survey.. ... 95
4.2.6 Baseline indicators of infection with other helminths.. ... 98
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CHAPTER FIVE - DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS
5.1 Introduction . 99
5.2 Performance . 103
5.2.1 Coverage ..... 103
5.2.2 Costs ..... 105
5.3 Impact ..... 113
5.3.1 Infection indicators . 117
5.3.2 Morbidity indicators . 119
5.3.3 Comparison between the longitudinal
and the cross-sectional surveys ..... 122
5.3.4 Comparison with disease control interventions
implemented elsewhere ..... 124
5.3.5 Drop-outs ..... 125
5.4 Conclusions and Recommendations .. 127
REFERENCES 131
APPENDICES ..... 156
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LIST OF FIGURES
Figure 1: Map of Burkina Faso showing areas targeted by the intervention in 2004
and 2005
Figure 2: Geographical distribution of the sentinel schools - including the one in
which no S. haematobium infection was found (Nabere) - within the
ecological areas of Burkina Faso
Figure 3: Chronological framework of activities aimed at assessing programme
impact
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LIST OF TABLES
Table 1: Definitions of the different indicators of coverage
Table 2: The structure of the health system in Burkina Faso
Table 3: Haemoglobin levels below which an individual is considered anaemic
Table 4: The gender distribution of children treated by the PNLSc, 2004 and 2005
Table 5: Details of the coverage achieved by the intervention, 2004 and 2005
Table 6: Summary of the major expenditures incurred at the different
administrative levels
Table 7: Expenditures by type of activity (US$)
Table 8: Allocation of resources by administrative level, excluding drugs (US$)
Table 9: Summary of costs per child treated achieved by the intervention (US$)
Table 10: Sensitivity analysis
Table 11: Prevalence of S. haematobium infection (longitudinal survey)
Table 12: Intensity of S. haematobium infection and proportion of heavy-intensity
infections (longitudinal survey)
Table 13: Prevalence of S. haematobium infection (cross-sectional survey, first-year
7-year-old schoolchildren)
Table 14: Intensity of S. haematobium infection (cross-sectional survey, first-year 7-
year-old schoolchildren)
Table 15: Prevalence of S. haematobium infection (cross-sectional survey, age-and
gender-matched control schoolchildren)
Table 16: Intensity of S. haematobium infection (cross-sectional survey, age-and
gender-matched control schoolchildren)
Table 17: Morbidity indicators in children successfully followed up at baseline and
first follow-up
Table 18: Indicators of infection with other helminths in the sentinel schools
(baseline, 2004)
Table 19: Strengths of the study design and major findings of the study
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LIST OF APPENDICES
Appendix I: Data collection form
Appendix III: Tally sheet (school-based distribution)
Appendix III: Tally sheet (community-based distribution)
Appendix IV: Gabrielli AF, Toure S, Sellin B, Sellin E, Ky C, Ouedraogo H, Yaogho M,
Wilson MD, Thompson H, Sanou S, Fenwick A (2006). A combined
school-and community-based campaign targeting all school-age children
of Burkina Faso against schistosomiasis and soil-transmitted helminthiasis:
performance, financial costs and implications for sustainability. Acta
Tropica 99:234-242
Appendix V: Koukounari A, Gabrielli AF, Toure S, Bosque-Oliva E, Zhang Y, Sellin B,
Donnelly CA, Fenwick A, Webster JP (2007). Schistosoma haematobium
infection and morbidity before and after large-scale administration of
praziquantel in Burkina Faso. Journal of Infectious Diseases 196:659-669
Appendix VI: Toure S, Zhang Y, Bosque-Oliva E, Ky C, Ouedraogo A, Koukounari A,
Gabrielli AF, Sellin B, Webster JP, Fenwick A (2008). Two-year impact of
single praziquantel treatment on infection in the national control programme
on schistosomiasis in Burkina Faso. Bulletin of the World Health
Organization 86:780-787
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LIST OF ABBREVIATIONS
APOC African Programme for Onchocerciasis Control
B&MGF: Bill and Melinda Gates Foundation
BMIZ: Body-mass-index z scores
CAMEG: Centrale d' Achat des Medicaments Essentiels Generiques
CDTI: Community-directed treatment with ivermectin
CHR: Centre Hospitalier Regional
CHU: Centre Hospitalier Universitaire
CM: Centre Medical
CMA: Centre Medical avec Antenne Chirurgicale
CSPS: Centre de Sante et de Promotion Sociale
DALYs: Disability-adjusted life years
DOT: Directly-observed treatment
DRS: Direction Regionale de la Sante
DS: District Sanitaire
epg: Egg per gram (of faeces)
FCFA: Franc de la Communaute Financiere Africaine
HAZ: Height-for-age z scores
Hb: Haemoglobin
IU: Implementation unit
MDA: Mass drug administration
MoE: Ministry of Education, Burkina Faso
MoH: Ministry of Health, Burkina Faso
MPDP Merck Praziquantel Donation Program
NGO(s) non-Governmentalorganization(s)
NTD(s) Neglected Tropical Disease(s)
PNLSc: Programme National de Lutte contre la Schistosomiase et les Vers
Intestinaux
PZQ: Praziquantel
RISEAL: Reseau International Schistosomoses, Environnement, Amenagement et
Lutte
SCI-ICL: Schistosomiasis Control Initiative - Imperial College, London
SG: Secretariat General
STH: Soil-transmitted helminth(s)
WHO: World Health Organization
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ABSTRACT
Schistosoma haematobium infection or schistosomiasis haematobia or urinary
schistosomiasis is the most common form of schistosomiasis affecting more than 60
million people in 46 sub-Saharan Africa countries. Symptoms and signs include chronic
pain, anaemia, inflammation, haematuria, fibrosis and calcification of the bladder and the
urinary and genital tracts, and ultimately bladder cancer. The disease is spreading as a
result of increase in irrigation and water impoundment schemes that favours colonization
by Bulinus spp. snail vectors. Treatment with praziquantel can prevent the development
of chronic morbidity and forms the basis of the WHO-recommended preventive
chemotherapy strategy for control of schistosomiasis. With this strategy, populations
groups at-risk, especially school-age children, are treated at regular intervals, at
frequencies determined by the levels of disease transmission. Treatment activities are
usually carried out in schools which provide easy access to school-age children; non-
enrolled school-age children, which can be many especially in rural areas, might however
be left untreated. Issues of costs, manpower, expertise and the vast geographical areas
have limited the implementation of disease control interventions in many countries to
either small-scale or pilot projects. Most intervention programmes have also lacked a
monitoring and evaluation framework which is key to achieving sustainability of control
programmes. Thus most studies have reported on performance and impact extrapolated
from results of small scale interventions. In 2003 the Ministry of Health of Burkina Faso
opted to implement a nation-wide intervention to cover all school-age children
irrespective of educational status, with support from the Schistosomiasis Control
Initiative-Imperial College London, and the Bill & Melinda Gates Foundation. This
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decision offered the opportunity, and the subject of thesis, to investigate the performance
and impact of a nation-wide programme relying on large-scale administration of
praziquantel to control urinary schistosomiasis. A characteristic of this programme was
its coordination by the Ministry of Health and use of only local human resources for its
implementation that combined both school-based and community-based channels. The
programme targeted each child eligible for treatment within a timeframe of 12 months
during 2004-2005 in all 13 administrative regions of Burkina Faso. The present study
investigated the programme's performance in terms of coverage and costs, and measured
infection and morbidity indicators to determine its impact using both longitudinal cohorts
and cross-sectional studies. Children aged 6-14 years were randomly selected from 16
sentinel schools in four regions located in the different ecological areas of Burkina Faso
and were recruited into the longitudinal cohort at baseline, approximately six months
before treatment. Infection indicators such as prevalence, intensity of infection and the
proportion of heavy-intensity infections, as well as morbidity indicators such as
haemoglobin concentration, anaemia status, microhaematuria and nutritional indexes,
were all measured using recommended protocols. The study also measured these
indicators cross-sectionally in newly enrolled children one year post-treatment to assess
the quality of the community-based delivery channel and in school children randomly
selected and matched by age and sex to those in the cohort in the second year, to validate
the results obtained for the longitudinal study. A total of 3,322,564 school-age children
were treated which was equivalent to a coverage of90.8% of the eligible population.
39.9% of the children were treated through schools whilst the majority, 60.1%, through
the community delivery channel. The total costs of the programme amounted to
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US$ 1,067,284, made up of delivery cost (US$ 325,936) and drug costs (US$ 741,348).
The delivery cost per child treated was US$ 0.098 and the full cost of treating each child
was US$ 0.32l.
Out of 1,727 children recruited in the original baseline longitudinal cohort, 1,131 and 763
were followed up in the first and second years respectively, thus 596 and 368 respectively
dropped out. Children that dropped out in the first year were mostly males (P<0.004),
older (P<O.OOl), more wasted (P<O.OOl) and more stunted (P<O.OOl) than those who
remained in the cohort. The parasitological parameters however did not differ
significantly between the two groups. Similarly, there were more male (P<0.05) and older
(P<0.01) children among the drop outs of the second follow-up. A significant increase in
Hb concentration from 109.7g/l at baseline to 112.5g/l, and a reduction in prevalence of
from 65.8% to 61.6%, were observed. Absence of haem aturi a increased from 50.4% to
89.5%. No significant changes were observed with nutritional indicators (wasting and
stunting). The prevalence of infection decreased significantly from 59.6% to 6.2% at the
first follow up and increased to 7.7% in the second year. Similarly the mean intensity of
infection decreased from 94.2 eggsllOml to 1.0 eggsllOml and increased to 6.8 eggsllOml
at the first and second follow-up respectively. The proportion of heavy-intensity
infections was reduced from 25% to 0.4% after year one and remained below 2% at the
end of the second year. A significant reduction of infection indicators 1 and 2 years post-
treatment was also registered by the two cross-sectional study components.
A combined school- and community-based drug distribution strategy was effective in
attaining high coverage rates of all school-age children in communities, and inclusion of
the community component did not significantly increase the budget. Drug costs were
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significant and fluctuations in cost of praziquantel might have a significant impact on
overall costs of the intervention. The analysis of the recurrent costs suggests that delivery
costs are expected to decrease further with each subsequent round of treatment. A
calendar of retreatment with single administration of praziquantel every two years or
more would be sufficient to control morbidity associated with urinary schistosomiasis,
but will require further research. For sustainable intervention programmes, savings from
the reduction in treatment frequency should be invested into strengthening the monitoring
and evaluation of programme, which is usually not accorded the needed importance. This
would allow for fine-tuning of the intervention strategies as programme implementation
progresses. The monitoring and evaluation should be mainly based on cross-sectional
surveys conducted at biennial intervals and include all children irrespective of
educational status, with the aim of verifying that children in both school and communities
have actually been targeted by the disease control intervention.
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CHAPTER ONE
GENERAL INTRODUCTION
1.1 Introduction
Schistosoma. haematobium is a trematode helminth that can cause infection in humans. It
predominantly affects the urinary tract and it is responsible for schistosomiasis
haematobia, or urinary schistosomiasis or, more appropriately, urogenital schistosomiasis.
Transmission of urinary schistosomiasis requires a final host (the human, as animal
reservoir is negligible), and a suitable intermediate snail host belonging to the genus
Bulinus.
Humans get infected when they come into contact with water contaminated with the
cercaria stage of the parasite, for recreational or professional purposes. The cercaria
penetrates the skin and transforms into a schistosomulum, which enters the blood
circulation and reaches the portal system. In the hepatic circulation, it matures to adult,
and in male-female pairs migrates and lodges in the vesical venous plexus, where the
female starts laying eggs.
Embryonated eggs are excreted in urine approximately 70 days after infection. In fresh
water, they hatch into miracidia that enter a snail host and develop into cercariae that
escape the snail and swim freely in water, thus continuing the cycle of infection.
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The clinical picture of S. haematobium infection can be divided in three chronological
phases. The first phase of cercarial penetration is usually manifested as an itchy eruption
known as swimmer's itch or cercarial dermatitis. The second phase of migration and
maturation of the schistosomula is associated with transient hypersensitivity and can be
associated with fever, fatigue, myalgia, rash and other allergy-type symptoms. The third
or chronic phase is characterized by lesions due to trapped eggs in the peri-vesical tissues.
Chronic infection with S. haematobium is characterized by loss of blood from the urinary
tract (haematuria), ureteral and bladder fibrosis and calcification, and vesico-ureteral
reflux eventually leading to hydro-ureteronephrosis. In addition, chronic inflammation of
the bladder wall can ultimately lead to bladder cancer.
Schistosomiasis remains one of the most prevalent parasitic diseases in developing
countries and is associated with a significant health and economic impact. Among the
continents, Africa is the most affected by schistosomiasis: S. haematobium is the most
prevalent species, followed by S. mansoni.
The prevalence of schistosomiasis follows a typical age and gender pattern. Age profiles
show a peak during school-age childhood (5 to 14 years). A general decline in prevalence
and intensity of infections is observed during adulthood. Differences in exposure to risk
of water contact, linked to behavioural or professional attitudes, explain such pattern.
Males are usually more affected than females.
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In terms of control, the questionable effect of the use of molluscicides as well as the
deleterious impact on the ecological system have now limited their use to low-endemic
areas as means to accelerate interruption of transmission. There is currently no effective
vaccine against human schistosomiasis. The mainstay of the WHO-recommended
strategy for schistosomiasis control focuses on decreasing and controlling morbidity
associated with infection. This is achieved by regular treatment with praziquantel, a safe
and efficacious WHO-recommended drug.
Praziquantel is usually delivered through large-scale interventions to individuals living in
areas where schistosomiasis is transmitted, without the need for individual diagnosis.
Such public health measure is cost-effective, rapid-impact, and made possible by the
dramatic reduction in the price of the drug in the last decades.
The main target of the large-scale distribution of praziquantel is school-age children of 5-
14 years who most frequently are in contact with cercaria-contaminated waters for
recreational reasons. The strategy however also contemplates as high-risk groups those
adults that for professional reasons are at risk of contracting the infection, such as
fishermen, farmers, irrigation workers or women in their domestic tasks, as well as those
that are not exposed to a higher risk of getting the infection but at higher risk of
developing the pathologic consequences of the infection, such as pregnant and lactating
women.
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The principles of the chemotherapy-based control of schistosomiasis were established in
May 2001, when the World Health Assembly adopted resolution WHAS4.19 which set
the target of providing treatment to at least 75 % of school-age children at risk of
morbidity in the world by 2010. More recently, such principles have been reaffirmed in a
WHO publication entitled Preventive chemotherapy in human helminthiasis that
promotes the integration of existing chemotherapy-focused strategies against the main
four helminth infections, namely schistosomiasis, lymphatic filariasis, onchocerciasis and
soil-transmitted helminthiasis. The key concept of preventive chemotherapy is that
delivery of anthelminthic drugs to population groups at-risk, at regular intervals, would
keep the number of the adult and/or larval stages of the worm infecting an individual at
low levels, thus curing early pathology and preventing the development of late-stage
lesions. The outcome would be a protection of the treated individual from the worst
consequences and the long-term sequelae of infection (WHO, 2006).
1.2 Rationale and objectives
A number of small-scale control interventions have registered great successes and
impacted significantly on schistosomiasis morbidity through the distribution of
praziquantel. However, the implementation of large-scale national programmes poses
major challenges especially in terms of financial resources and logistics.
Because of the limited or small scale of most implemented control activities, performance
and impact associated with the implementation of nation-wide disease control
programmes by health systems have been little studied. Moreover, relatively few among
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such studies have been conducted in sub-Saharan Africa. Finally, issues such as the most
appropriate drug delivery channels, compliance to the intervention, use of appropriate
incentives, and long-term sustainability still remain subjects of debate.
Nevertheless, performance and impact play an essential role in the assessment of the
quality of a national disease control programme and should therefore be dedicated
attention and importance. The demonstration of the fact that the desired impact has been
achieved as an outcome of a defined series of inputs can help better define and
understand the quality of an intervention in terms of accountability, usefulness, and
efficiency. More practically, quantification of impact and performance of a health
programme can be used for a number of activities such as responding to public enquiries
about the programme; educating decision makers; demonstrating that funds have been
appropriately spent; increasing the awareness of the programme among the target
population; showing progress made towards the achievement of an objective; mobilizing
financial and human resources (CDC, 2007; Walford, 2007).
In 2003, the Schistosomiasis Control Initiative, based at Imperial College, London (SCI-
ICL) obtained a grant from the Bill and Melinda Gates Foundation to support
implementation of schistosomiasis control activities in six sub-Saharan African countries
including Burkina Paso.
The overall aim ofSCI-ICL was to provide financial support to a number of
Governments of endemic countries so that these could develop sustainable national
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schistosomiasis control programmes compliant with the WHO recommendations of large-
scale provision of praziquantel, for a period of five years. A primary objective of these
SCI-ICL-supported programmes was to achieve, and hence also demonstrate, a
quantifiable reduction in schistosome-associated morbidity as a consequence of such
chemotherapeutic intervention (Fenwick & Webster, 2006). In 2003, all the Ministries of
Health of sub-Saharan African countries that are schistosomiasis-endemic were invited to
apply for financial support from the SCI-ICL. An international and independent panel
was set up to select the six most compelling national plans of action. The national
schistosomiasis control programme of Burkina Faso was one of the successful applicants
together with Mali, Niger, Uganda, the United Republic of Tanzania and Zambia. Some
of the other countries including Ghana were either directly or indirectly supported with
smaller-scale financial and/or in-kind donations (Fenwick et al., 2009).
In Burkina Faso, control activities against schistosomiasis were implemented under the
leadership and coordination of the MoH's Programme National de Lutte contre fa
Schistosomiase et fes Vers lntestinaux (PNLSc). The PNLSc adopted the WHO-
recommended strategy of preventive chemotherapy, and decided to implement large-scale
administration of praziquantel to individuals of school-age living in all areas at-risk of
schistosomiasis in the country. After several months of preparation, treatment activities
started in 2004 and took the form of a nation-wide campaign coupled with mobilization
efforts to achieve high treatment coverage. Also from a financial perspective, all the
necessary resources were allocated and managed through the health system of Burkina
Faso.
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The implementation of such nationwide intervention offered the opportunity to
investigate and document its performance and impact, which is the subject of this thesis.
In particular, here is taken into account the first nationwide schistosomiasis campaign,
which was implemented in two phases (October 2004 and October 2005).
1.2.1 General objectives
The overall goal of the study was to assess the performance and the impact achieved by a
national schistosomiasis control programme that followed the WHO-recommended
preventive chemotherapy strategy and implemented large-scale distribution of
praziquantel to school-age children in Burkina Faso, over a period of two years.
Performance was assessed in terms of coverage and cost of the programme's activities
during the period, while the impact of the programme's activities was determined by
monitoring the effects of praziquantel on parasitological and morbidity indicators one and
two years after treatment.
The characteristics of the different programme's delivery channels (schools and
communities) were also assessed both in terms of performance and in terms of impact.
1.2.2 Specific objectives
The specific objectives set to investigate the performance of the large-scale distribution
of praziquantel were:
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i) To determine the geographical, epidemiological and programme coverage
achieved by the large-scale distribution of praziquantel (see Table 1 for
definitions );
ii) To describe and analyse the allocation and expenditure of resources as well as
to calculate the financial costs of the implementation of the large-scale
distribution of praziquantel..
The specific objectives set to assess the impact of the large-scale distribution of
praziquantel were:
iii) To determine the effect of the large-scale distribution ofpraziquantel on
schistosomiasis infection and morbidity indicators one and two years after
treatment among children treated via schools (through a longitudinal cohort
survey and a control cross-sectional survey);
iv) To determine the effect of the large-scale distribution of praziquantel on
schistosomiasis infection indicators one and two years after treatment among
children treated via communities (through a cross-sectional survey).
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CHAPTER TWO
LITERATURE REVIEW
2.1 Schistosomiasis: an introduction
Schistosomiasis (commonly called bilharziasis or inappropriately, bilharzia) is a parasitic
helminth infectious disease that in humans is caused by any of five species of flatworms
belonging to the genus Schistosoma, within the class trematodes. These species are
Schistosoma haematobium, S. mansoni, S. japonicum, S. intercalatum and S. mekongi.
While the first species predominantly affects the urinary tract and is responsible for
schistosomiasis haematobia, also called urinary schistosomiasis or more appropriately
urogenital schistosomiasis, as recently recommended by a WHO Working Group (WHO,
2010d), the other four species affect the intestinal tract and the liver and are therefore
responsible for intestinal and hepatic schistosomiasis.
2.1.1 Transmission
Schistosomes have life-cycles involving obligatory alternation of generations between
sexual reproduction in the final host (a mammalian, such as man) and asexual
reproduction in the intermediate host (a freshwater snail mollusc). In freshwater, free-
living schistosome larvae (miracidia, singular: miracidium) hatch from eggs laid by the
adult female worm in the final host and passed out in the urine or in the faeces, according
to the species. Miracidia then invade a suitable intermediate snail hosts which belong to
different genera of snails depending on the different schistosome species. The
intermediate hosts of S. haematobium and S. intercalatum belong to the genus Bulinus,
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that of S .mansoni to the genus Biomphalaria, and those of S japonicum and S mekongi
belong to the genera Oncomelania and Neotricula respectively.
Following the penetration in the snail, the miracidium develops into sporocysts by
asexual replication, which leads to the production of thousands of cercariae. The
cercariae then leave the snail and swim freely in the water until the moment when they
infect definitive mammalian hosts including humans. This asexual replication stage of the
life cycle takes approximately 4-6 weeks. The cercariae penetrate the skin of the final
host when the latter comes into contact with contaminated water as it is the case of
children playing in rivers and streams, women fetching water or engaging in domestic
tasks and men swimming, fishing and engaging in irrigated farming.
During skin penetration the cercaria loses its tail and transforms into another larval stage
called the schistosomulum which then enters the venous circulation and migrate to the
lungs in three to four days. The schistosomula squeeze through the pulmonary capillaries
and are carried through the left heart to the systemic circulation and then through the
mesenteric artery to the portal system. In the hepatic circulation, the schistosomes mature
to adult and migrate in pairs to the vesical venous plexus (S haematobium) and to the
mesenteric and rectal veins (S mansoni) where they lodge and mate. Embryonated eggs
are excreted in urine and/or faeces after approximately 70 days in S haematobium
infections and 35 days for S mansoni (Molyneux, 2006; Webster, Gower & Norton,
2008). Once excreted the eggs hatch into free-living larvae which infect snails to continue
the transmission cycle.
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The duration of the life cycle of human schistosomiasis varies according to the
schistosome species and is also dependent on environmental factors such as temperature
and water quality as well as on the number of miracidia that enter and survive in the
intermediate snail host.
2.1.2 Clinical manifestations
Each of the three phases of the schistosomes' life cycle in the human host is characterized
and marked by clinical implications (Mahmoud, 2001; Cook & Zumla, 2008).
The first phase of host penetration by cercariae is usually manifested as a transient,
immuno-mediated itchy eruption that occurs soon after exposure, which may last for a
few hours and is known as "swimmer's itch" or cercarial dermatitis (Cook & Zumla,
2008).
The second phase of migration and maturation of the schistosomula into adult worms is
also associated with transient (a few weeks to months) hypersensitivity, which gives rise
to an associated clinical syndrome known as acute schistosomiasis. This phase is most
severe in patients infected with S. japonicum, in which it is known as "Katayama" fever
or "Katayama" syndrome (Doherty, Moody & Wright, 1996). It starts suddenly with
fever, fatigue, myalgia, malaise, non-productive cough, and is characterized by
eosinophilia, and patchy infiltrates on chest radiography. Most patients recover
spontaneously after two to ten weeks, but some, especially those infected with S.
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japonicum, develop persistent and more serious disease with weight loss, dyspnoea,
diarrhoea, diffuse abdominal pain, hepatosplenomegaly and widespread rash.
The third or the chronic phase starts when worms mature and become adult. It is the
phase characterized by the most significant pathology, which is produced by the laid eggs
that are trapped in either the vesical or intestinal tissues (most notably the mucosa)
depending on the species. Embolisation of the eggs in the liver, spleen, lungs, or
cerebrospinal system is also possible (Gryseels et al., 2006). Human infection with S.
mansoni is associated with chronic hepatic and intestinal inflammation and fibrosis,
whilst S. haematobium infections have been shown to be associated with haematuria,
ureteral and bladder fibrosis, calcification of the uri!lary tract, and vesico-ureteral reflux
eventually leading to hydro-ureteronephrosis (Koukounari et al., 2006b). The retention of
schistosome eggs within the bladder's wall and the consequent chronic inflammatory
response can lead to bladder cancer (Vennervald & Dunne, 2004).
2.1.3 Pathogenesis of S. haematobium infection
The eggs of S haematobium are responsible for diffuse inflammation of the mucosa of the
urinary tract, associated with formation of granulomas. The granulomas are tumour-like
nodules composed of fibroblasts and several types of white blood cells (Crompton &
Savioli, 2007). Accumulation of granulomas can give rise to ulcerations as well as
masses in the vesical and ureteral walls. The masses can take the shape of a more or less
pronounced thickening of the wall, of a protuberance, or of a peduncolated pseudopolyp
(TDR, 2000). Common early symptoms and signs of infection include dysuria (painful
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urination), pollakisuria (frequent urination), proteinuria and especially haematuria. In
infected individuals, haematuria can frequently be observed on visual inspection. In this
case it is defined as macrohaematuria. In endemic areas, this sign is significantly
associated with schistosomiasis, especially in school-age children. In rural communities,
it can be confused with menstruation in girls and considered as a sign of coming of age in
boys. Typically, blood is first seen in the terminal urine, but in severe cases the whole
urine sample can be affected. The colour of haem aturic urines can vary from light to dark
red. Even urines that appear as normal at visual inspection can however contain minute
quantities of red blood cells, a finding which is referred to as microhaematuria. Bacterial
superinfection, blood coagula and bladder stones can complicate the clinical picture.
Haematuria is the outcome of acute inflammation of the bladder wall, and as such might
be less common after adolescence, as a consequence of reduced exposure to
contaminated water and reinfection. In non-treated populations exposed to S
haematobium, microhaematuria has been found in 41-100% of infected children, while
visible haematuria may range between 0-97% (WHO, 1993; Gryseels et al., 2006;
Crompton & Savioli, 2007).
The progression of the inflammation towards its chronic stages can lead to fibrosis or
calcification of the bladder and lower ureters, resulting in hydroureter and hydronephrosis.
The reflux of urine towards the kidneys can eventually produce damage to the
parenchyma of the kidneys; radiologically visible lesions in the upper urinary tract have
been observed in 2-62% of infected individuals, however kidney function is usually well
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preserved and kidney failure is infrequent (WHO, 1985; Gryseels et al., 2006; Crompton
& Savioli, 2007).
In addition, S. haematobium infection is almost constantly associated with lesions in the
genital tract of both men and women (Gentilini et al., 1986; Kjetland et al., 2005). These
lesions are being investigated as possible risk factors for transmission of sexually-
transmitted infections and HIV-AIDS (Feldmeier, Krantz & Poggensee, 1994 and 1995;
WHO,2010d)
Studies conducted mainly in endemic African countries including Egypt, Tanzania and
Zimbabwe have shown that chronic urinary schistosomiasis is epidemiologically
associated with squamous bladder cancer. In Egypt, the occurrence of bladder cancer has
decreased over the years, following a reduction in prevalence of infection as a
consequence of the implementation of large-scale control interventions (WHO, 1985;
Gryseels et al., 2006; Crompton & Savioli, 2007). The WHO's International Agency for
Research on Cancer (IARC) states that "there is sufficient evidence in humans for the
carcinogenicity of infection with Schistosoma haematobium" and has concluded that
"infection with Schistosoma haematobium is carcinogenic to humans", therefore
including it into the Group 1 (lARC, 1994).
2.2 The global burden of schistosomiasis
Schistosomiasis remains one of the most prevalent parasitic diseases in developing
countries (Engels et al., 2002). From a public health perspective, schistosomiasis is the
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most important tropical disease in terms of morbidity in humans, after malaria, and it is
associated with a significant health and economic impact (WHO, 1993).
Schistosomiasis is also considered among the neglected tropical diseases (NTDs). Recent,
wide reconsideration of the entire burden ofNTDs (Engels & Savioli, 2002), coupled
with detailed investigations on the pathological consequences of specific infections have
indicated that the impact of such group of diseases on human health is a much more
serious problem from both clinical and public health perspectives than previously
perceived.
A number of authors have called for a recalibration of the estimate of the schistosomiasis
public health burden (King & Dangerfield-Cha, 2008). A meta-analysis of performance-
related symptoms and disability-linked morbidity in schistosomiasis patients (King,
Dickman & Tiesch, 2005) suggests a 4 to 30 times greater disability, expressed as
disability-adjusted life years (DAL Ys) than original calculations based on official
estimates of active cases of infection only (Murray & Lopez, 1996; Michaud, Gordon &
Reich, 2004). The significant burden represented by chronic disability is caused by a
wide range of conditions that affect schistosomiasis-infected patients in addition to the
more obvious overt morbidity (King, 2010). Such conditions include chronic pain,
diarrhoea, exercise intolerance and undernutrition which collectively are known as
"subtle morbidity". Anaemia is also included among the subtle morbidity associated with
any forms of schistosomiasis. In S. haematobium infection, anaemia is the consequence
of the loss of blood and iron in the urine, and the consequent decrease in haemoglobin
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(Hb) concentration (Nelson, 1958; Farid et al., 1968; Stephenson et al., 1985; Prual et al.,
1992; Tohon et al., 2008).
Schistosomiasis has also been reconsidered as a cause of death and an annual mortality of
280,000 cases directly attributable to schistosomiasis in sub-Saharan Africa in 2002 has
been proposed (van der Werf et al., 2003). This figure is far greater than the 15,000 per
year worldwide estimated by WHO for the same year (WHO, 2004). Furthermore, the
more recent estimate of 779 million people at risk and 207 million people infected with
schistosomiasis in 76 countries worldwide in mid-2000 translates to increments of 12.6 %
and 7.2 % respectively (Steinmann et al., 2006) when compared with estimates for the
mid-1990's (Chitsulo et al., 2000).
In sub-Saharan Africa, urinary schistosomiasis is the most widespread form of the
infection and the estimated number of infected individuals was 112 million in 2003,
while about 54 million were estimated to be infected with S. mansoni (van der Werf,
2003). In Africa, schistosomiasis is transmitted in 46 countries; globally, it is estimated
that 97% of all infected individuals and 85% of the individuals living in areas where
schistosomiasis is transmitted live in Africa (population at-risk) (Steinmann et al., 2006).
2.3 Epidemiology of schistosomiasis
Prevalence of infection with schistosomiasis follows a characteristic age and gender
pattern. Age profiles among affected populations typically show a peak in school-age
childhood (5 to 14 years). There is a characteristic increase in prevalence and intensity of
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infection from the youngest school-age groups to the early teenagers, followed by a
subsequent decline in the mid- to late teenagers age groups (Booth et al., 1998;
Ndyomugyenyi & Minjas, 2001; Bowie et al., 2004; Clennon et al., 2004; Clements et al.,
2008). Such decline continues in the adult life, which is usually characterized by a
lowered risk of infection, with exceptions found among inhabitants of communities
whose activities are associated with specific practices, such as fishermen or irrigation
workers (WHO, 2006).
As mentioned above, such epidemiological pattern finds its principal explanation in
differences in exposure to risk factors for transmission mainly through water contact,
which are attributable to either behavioural or as in the case of fishing communities to
professional activities. Physiological changes at puberty leading to lower susceptibility
(including interactions between hormonal, anatomical and immunological changes) have
also been suggested, as well as the development of acquired immunity (Feldmeier,
Poggensee & Krantz, 1998; Fulford et al., 1998; Mutapi et al., 2006). Higher prevalence
and intensity of infection are usually reported in males than females (Ansell et al., 2001;
Ndyomugyenyi & Minjas, 2001; Bowie et al., 2004; Clements et al., 2008), though
exceptions have also been documented (Mafe et al., 2000). Different gender patterns in
prevalence and intensity of infection might also be attributed to a different immune
response between males and females (Marguerite et al., 1999; Remoue et al., 2001).
The tendency to urinate and defecate in and around water is an important behavioural
characteristic of humans in endemic areas on which relies the entire schistosomiasis life
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cycle. In principle, if human behaviour could be changed to stop contamination of water
bodies with urine and faeces containing schistosome eggs, then transmission of the
parasite would significantly decrease and possibly cease in the case of S. haematobium
and S. mansoni, which have no significant animal reservoir (Cook & Zumla, 2008;
Crompton & Savio li, 2007). In the case of other species, the animal reservoir plays an
important role in maintaining transmission and therefore interventions that target only the
human host are unlikely to produce a major impact on transmission.
The increase in the realization of water resource development projects and irrigation
schemes in the effort to meet food and energy demands, as well as the subsequent
increased concentrations of human settlements and of water contact, have been shown to
increase likelihood of infection. In 2003, it was estimated that 106 million individuals
were living in irrigation schemes at-risk of schistosomiasis (Steinmann et al., 2006). The
consequence is a higher prevalence and a heavier intensity of infection in such
individuals, whose main consequences are more eggs reaching the water (and therefore
increased transmission), and greater human pathology and morbidity (Steinmann et al.,
2006).
2.4 Control of schistosomiasis
There is currently no effective vaccine against human schistosomiasis, in spite of a
number of attempts made in the past and ongoing research activities (Hotez & Brown,
2009).
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The reduction in water contamination by infected human hosts is central to many longer-
term control efforts. This strategic approach requires the provision of health education
messages, especially to children who form the group most significantly contributing to
water contamination. Provision of environmental sanitation and safe water also constitute
essential forms of longer-term control (Fenwick, 2006).
The intricate relationship between snail and schistosome makes the part of the life cycle
stage in molluscs vulnerable to control activities. In fact there has been a long history of
snail control interventions using chemicals (molluscicides) to kill snails or relying on
biological control technologies. Snails of the Bulinus and Biomphalaria molluscan genera
thrive in areas frequented by humans. Indeed these snail species seem to prefer habitats
polluted with human excreta and the detritus of everyday living, thus increasing the
chance of contact with water contaminated with cercariae. However, despite the clear
evidence that the population of snails can be much reduced through molluscicides, the
latter are not specific to killing just molluscs. For example, fishes are also killed and
therefore this measure of control can have a deleterious impact on the environment, on
biodiversity and most importantly from the perspective of affected communities on food
security.
2.4.1 Current strategy for control
The mainstay of the WHO-recommended strategy against schistosomiasis currently
focuses on treatment of the human host. The goal is to mitigate the burden of disease on
affected individuals by controlling morbidity associated with infection (WHO, 2006;
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Fenwick & Webster, 2006). The tool identified to achieve such goal is treatment with
praziquantel, the only WHO-recommended drug for treatment of infection with S.
haematobium (in contrast, S. mansoni can be treated alternatively with oxamniquine)
(WHO, 2009). Treatment of infected individuals is also expected to produce a decrease in
egg contamination of fresh water and consequently a reduction in transmission, however
decrease in transmission rates is not currently contemplated by WHO strategies (WHO,
2002 and 2006).
The principles of the chemotherapy-based control of schistosomiasis were instituted in
May 2001 when the World Health Assembly adopted the Resolution WHA54.19 which
included schistosomiasis and soil transmitted helminthiasis among the public health
priorities of WHO and its member states, and set the target of providing treatment to at
least 75 % of the school-age children at risk of morbidity by 2010 (WHO, 2002). These
principles have been reaffirmed in a recent WHO publication that has synthesized in a
single document the current chemotherapy-focused strategies against the main helminth
infections namely schistosomiasis, lymphatic filariasis, onchocerciasis and soil-
transmitted helminthiasis, in an effort to integrate and coordinate helminth control
interventions at country level. This manual is entitled Preventive chemotherapy in human
helminthiasis and was published in 2006 (WHO, 2006). The rationale of preventive
chemotherapy is that the delivery of anthelminthic drugs, at regular intervals, will keep
the number of the adult and/or larval stages of the worm at low levels in infected
individuals, thus curing early pathology and preventing the development of late-stage
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pathology, thereby protecting the treated individual from the worst consequences and the
long-term sequelae of infection (WHO, 2006).
2.4.1.1 Preventive chemotherapy
Following WHO recommendations, the treatment with praziquantel in schistosomiasis
endemic areas is usually delivered through large-scale interventions, at regular intervals,
with the aim of relieving affected individuals from the burden of the morbidity associated
with the infection. In this context specific high-risk groups are treated, without the need
for individual diagnosis. Preventive chemotherapy for schistosomiasis and other helminth
infections has been identified by the scientific community to be among the most cost-
effective and rapid-impact interventions existing in public health (Molyneux, Hotez &
Fenwick, 2005; Hotez et al., 2007a; Hotez et al., 2009). With regard to schistosomiasis,
in the past, some degree of indifference or apathy, or even rejection or outright refusal to
participate in mass treatment activities has been exhibited by the targeted populations
(Sellin et al., 1986) but this has not been the case in recent times which are characterized
by a good and often excellent compliance. Large-scale distribution of praziquantel has
been made possible by the dramatic reduction in the price of the drug in the last decades.
The cost of treatment of a child has decreased from US$ 4 in the early 1990s to US$ 0.25
at present (Lammie, Fenwick & Utzinger, 2006). This major development was made
possible by the discovery of a new method for synthesizing the drug, which resulted in a
significant decrease in production costs (Fenwick, Rollinson & Southgate, 2006).
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The main target of the distribution of praziquantel for control of morbidity associated
with any form of schistosomiasis is represented by school-age children (5-14 years) who
are most exposed to cercaria-contaminated waters for reasons of their recreational
activities which centre around freshwater bodies. In areas characterized by high risk
however, the strategy also contemplates as target groups those adults who for
professional reasons are exposed to high risk of contracting the infection, such as
fishermen, farmers, irrigation workers or women in their domestic tasks, as well as those
that are not at higher risk of infection but are at higher risk of developing the associated
pathologic consequences, such as pregnant and lactating women (WHO, 2006).
Schools and communities are the two privileged delivery channels for large-scale
distribution of anthelminthic drugs in the context of preventive chemotherapy
interventions. Considering that the main target of schistosomiasis control programmes is
represented by school-age children, primary and secondary schools have represented the
most frequent and natural choice in most endemic countries.
Schools are increasingly recognized as effective complementary health outposts in
developing and middle-income countries, especially when the target of the health
intervention is represented by school-aged population. The association between school
and health is not limited to the obvious consideration that the pre-existing infrastructure
of the educational system offers a suitable environment for delivering health services to a
captive population; it also moves from the fact that good health is a prerequisite for
effective learning (Bundy et al., 2006).
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One of the most significant challenges encountered by public health interventions relying
on schools as the exclusive delivery channel for health products is reaching non-school-
enrolled children. Several studies have stressed the need to include such children in
activities directed against helminth infections (reviewed by Olsen, 2003) and have
highlighted that delivering anthelminthic drugs through the school channel is unlikely to
reach large numbers of these children in resource-poor social settings (Husein et al., 1996;
Olsen, 1998; Mafe et al., 2005). There are a few success stories though but these have
been implemented on a small-scale (Talaat, Omar & Evans, 2000), and have therefore
benefited from a degree of coordination and supervision unlikely to be achieved in large-
scale interventions, or have occurred under specific social conditions. For example, in
Zanzibar most non-enrolled school-age children could be mobilized because they shared
the same households with enrolled children thus fostering their adherence to treatment
(Montresor et al., 200 1b). It should be noted however that the population density in
Zanzibar is significantly high, about seven-fold that of Burkina Faso (UNDESASD,
2010), a factor that is likely to facilitate interpersonal communication and social
mobilization.
In order to overcome such challenge, or when the target population is not restricted to
children, community-based interventions have been designed and developed. Such
interventions imply a significant involvement of target communities into the planning and
implementation process of a health intervention. In the mid-1990s community-based
interventions were adopted by the African Programme for Onchocerciasis Control
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(APOC) as its mainstay strategy for delivery of ivermectin to communities endemic for
onchocerciasis, even though it was already operational in several countries and already
adopted by a number of West-African onchocerciasis control programmes
(UNICEF/UNDP/World Bank/WHO, 1996). The successful experience of community-
directed treatment with ivermectin (CDT!) for onchocerciasis control purposes has
elicited significant interest in adapting community-based interventions to other public
health settings. A recent evaluation of the applications of this strategy to other domains
has shown its versatility, efficiency and effectiveness, particularly in the African context
(CDISG,2010).
2.4.1.2 Praziquantel as the drug of choice for schistosomiasis control
Praziquantel is a heterocyclic pyrazino-isoquinoline whose efficacy is not influenced by
the geographical origin of the parasite species, or the age, sex, the type or origin of the
mammalian host (WHO, 1985). In spite of the significant amount of research that has
been carried, the mechanism of action of praziquantel is not yet fully elucidated at the
molecular level. It is however known to be associated with disruption of the parasite's
tegument, vesicle formation and paralytic muscular contraction (Fenwick, Rollinson &
Southgate, 2006).
The treatment regimen currently recommended by WHO is 40-60 mg/kg single
administration. In large-scale interventions, the appropriate dosage is administered by
using the WHO dose-pole (Montresor et al., 2001a; WHO, 2006). This tool has been
developed for field use through extensive studies that established the relationship
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between height and weight, and involved a large number of school-age children from
developing countries, and assigned the number of tablets of praziquantel 600mg to be
administered to specific heights. The dose-pole is currently the tool recommended by
WHO for field operations (WHO, 2006) and has replaced dose determination by weight
which is a time-consuming exercise and therefore poorly suited for large scale
interventions.
Praziquantel is effective against adult worms, and has little or no effect on eggs and
immature worms. The cure rates for S. haematobium infection in the field have been
shown to be usually between 80% and 95% but can be as high as'100% (WHO, 1985;
Gryseels et al., 2006). The reduction in egg count (intensity of infection) in those that are
not cured can also be very high, usually equivalent to or higher than 95%, one year after
treatment provided no re-infection takes place. Cure rates and egg reduction rates are
usually lower in individuals infected with other Schistosoma spp, but are usually not
lower than 70% or 90% (WHO, 1985; Gryseels et al., 2006).
The marked reduction in egg counts produced by praziquantel reflects and follows the
death of adult schistosomes harboured in the body of infected individuals. This fact is not
only associated with an arrest in the progression of morbidity towards its more chronic
stages, but also with a reversal of existent lesions. A number of studies conducted a few
weeks to a few months to a few years after administration ofpraziquantel (and also of
other medicines previously in use for treatment of schistosomiasis) have documented the
resolution of S. haematobium-associated pathological lesions such as bladder wall
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thickening, polyps, and protruding masses, as well as the significant improvement of the
associated mechanical obstruction of the urinary tract, and the consequent hydro-
urethero-nephrosis (Lucas et aI., 1966 and 1969; Doehring et al., 1986; King et ai, 1988;
Devidas et al., 1989; Laurent et al., 1990; Hatz et al., 1990;, Kardorff et al., 1994;
Richter, 2000). In the case of S. mansoni, a decrease in periportal fibrosis associated with
the most advanced stages of infection has been reported after treatmemt (Homeida et al.,
1988, 1991 and 1996; Mohamed-Ali et al., 1991; Doehring-Schwerdtfeger et al., 1992;
Boisier et al., 1998; Frenzel et al., 1999; Berhe et aI., 2008), even though the underlying
mechanism has not been fully elucidated yet. Regression of periportal as well as liver
parenchimal fibrosis has also been observed in S. japonicum infection (Li et al., 2000 and
2002; Carlton et al., 2010), whilst reversal of fibrosis of the urinary tract has not been
described in S. haematobium infection.
The magnitude and the time-frame of reversal of the lesions vary according to the
severity of the infection and to the severity and time stage of the lesions, as well as to the
different methods used. In S. haematobium infections, infection indicators such as
intensity of infection drop dramatically after treatment; decrease of haematuria and
microhaematuria follow, and the majority of the organ detectable pathology achieve
maximal reversal around six months after treatment (Hatz et al., 1990; Hatz et aI., 1998;
Richter, 2003). Overall, reversal of morbidity follows and is correlated with reductions in
prevalence and intensity of infection: in this regard, acute lesions have been shown to
regress quicker and more completely than chronic lesions (Crompton & Savioli, 2007). In
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endemic areas, resurgence of pathology as a consequence ofre-infection can be observed
from 12 to 18 months after treatment.
The high safety and efficacy of praziquantel in treating infection with Schistosoma spp.
has been established and is well documented under various experimental and clinical
settings (Kardaman et al., 1983; Nokes et al., 1999; Kabatereine et al., 2003; King et al.,
2002). Most in-vitro studies however have rather focused on species other than S.
haematobium, possibly because of the more demanding conditions for its laboratory
maintenance (Botros et al., 2005).
Field experience confirms that praziquantel is a well-tolerated drug. The main adverse
events associated with its administration are abdominal discomfort with or without pain,
diarrhoea, dizziness, nausea, sleepiness and vomiting. Fever and skin rash have also been
reported but more rarely. Such events are less frequent in individuals infected with S.
haematobium than in individuals infected with other schistosome species. There seems to
be a direct proportionality between frequency and severity of adverse events and intensity
of infection, which suggests an indirect mechanism of generation of adverse events, that
would not be linked to the action of the drug itself, but rather to the biological substances
released by the dying worms through their disrupted tegument (WHO, 1985; Fenwick,
Rollinson & Southgate, 2006).
2.4.2 The assessment of performance and impact of praziquantel-based
schistosomiasis control interventions
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Since the inception of the large-scale use of anthelminthic drugs against schistosomiasis,
both programme managers and researchers have focused on two main aspects of
interventions, namely performance and impact. These are regarded as key tools providing
information on the overall quality of an implemented intervention and also have
significant implications for the sustainability of the control strategy.
2.4.2.1 Performance
A number of studies have examined the performance of interventions delivering
praziquantel or other anthelminthic drugs to population groups at-risk, through
population-based drug distribution channels (either school-based or community-based).
However, most of them have focused on selected aspects of performance, such as costs
alone (Guyatt, Bundy & Evans, 1993; Guyatt et al., 1994; Holland et al., 1996;
Partnership for Child Development. 1998 & 1999; Mascie- Taylor et al., 1999; Curtale et
al., 2003; Guyatt, 2003; Montresor et al., 2004; Kabatereine et al., 2005 & 2006b; Sinuon
et al., 2005; Brooker et al., 2007; Montresor et al., 2007; Phommasack et al., 2008;
Croce et al., 2010) or on coverage alone (WHO, 2010b).
Among those considering costs, most have focused on pilot, small-scale interventions
(Guyatt, Bundy & Evans, 1993; Guyatt et al., 1994; Holland et al., 1996; Partnership for
Child Development. 1998 & 1999; Mascie- Taylor et al., 1999; Guyatt, 2003). On the
contrary, a very limited number of studies have focused on nationwide helminth control
interventions, none of which focused on a sub-Saharan African country. Sinuon et al.
(2005) investigated the financial costs of distributing mebendazole for control of soil-
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transmitted helminth (STH) infections in all primary schools of Cambodia; with a similar
approach, Phommasack et al. (2008) studied coverage and direct (financial) costs of
distributing the same drug for the same purposes in all primary schools of the
neighbouring Lao People's Democratic Republic; finally, by using a different approach
and with a different scope from that of the present thesis, Croce et al. (20 I0) assessed the
cost-effectiveness of the Cambodian schistosomiasis control programme over 12 years of
activities.
As mentioned, most analyses have been performed on a subsection of the programme
(sub-national scale) only (Kabatereine et al., 2005 & 2006b; Brooker et al., 2007;
Montresor et al., 2007), while others have rather focused on projections than on actual
data (Montresor et al., 2004). In addition, most of the studies analysed only school-based
delivery of tablets either because this was the only implementation strategy or because
schools were the only focus of the analysis, in spite of the fact that community-based
interventions were also being implemented. The performance of various albendazole or
mebendazole based interventions for control of STH infections in school settings has
been reviewed recently by Montresor et al. (2010).
The WHO recommends three different coverage parameters for monitoring and
evaluating the performance of preventive chemotherapy interventions. These are
geographical coverage, epidemiological coverage, and programme coverage (WHO,
2010a) [Table 1]. Geographical coverage is defined as the proportion of the eligible
implementation units (IUs) that was covered by the intervention. Epidemiological
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coverage (also called the national coverage) is the proportion of eligible individuals who
received treatment, while programme coverage is the proportion of the targeted
population that received treatment. In case a programme reaches nationwide coverage,
the target population is the same as the eligible population and therefore epidemiological
coverage and programme coverage coincide.
2.4.2.2 Impact
A number of studies have also investigated the impact of praziquantel treatment for
schistosomiasis control in endemic countries, both in terms of infection and morbidity. A
substantial number of such studies focus on urinary schistosomiasis: in the Republic of
the Congo (Doehring et al., 1986), in Kenya (King et al., 1988; King et al., 1990;
Magnussen et al., 1997; Subramanian et al., 1999), in Niger (Devidas, 1989; Laurent et
al., 1990; Campagne et al., 2001), in Tanzania (Hatz et al., 1990; Hatz et al., 1998;
Reimert et al., 2000), in Mali (Kardorff et al., 1994; Koukounari et al., 2006b), in Egypt
(Medhat et al., 1997), in Senegal (Delegue et al., 1998) and in Ghana (Wagatsuma et al.,
1999). These studies have generally confirmed the efficacy of praziquantel and the fact
that treatment results in a decrease in infection indicators and a regression of
schistosomiasis-induced morbidity. However studies have also suffered from the
interventions either being small scale or pilot projects.
Infection indicators used for the assessment of the impact produced by treatment with
praziquantel mainly involve the microscopic detection of parasite eggs in urine or stool
specimens from which the prevalence and intensity of infections are determined.
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Morbidity indicators rely on clinical examinations and include: macrohaematuria,
microhaematuria, measurement of nutritional status as well as parameters detected by
ultrasonography.
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Table 1: Definitions of the different indicators of coverage (WHO, 201Oa).
Geographical coverage Number oflUs where PC* is implemented
---------------------------------------------------------
Number oflUs eligible for PC*
Epidemiological coverage Number of individuals treated
-------------------------------------------------------
Number of individuals eligible for PC*
Programme coverage Number of individuals treated
----------------------------------------------------------
Number of individuals targeted by PC*
* pc: preventive chemotherapy
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2.5 Schistosomiasis in Burkina Faso
2.5.1 Epidemiology of schistosomiasis in Burkina Faso
Urinary schistosomiasis caused by Schistosoma haematobium and intestinal
schistosomiasis caused by S. mansoni occur in Burkina Faso. The transmission of S.
intercalatum reported by Becket & Saout (1969) has not been confirmed since then so
today it can be excluded. Schistosoma bovis and S. curassoni, two species that infect
domestic husbandry but not humans have been reported in studies conducted in
slaughterhouses in Ouagadougou and Bobo-Dioulasso (Bara et al., 1998).
The earliest studies on schistosomiasis in then Upper Volta date back to the period of the
second world war (1940-1945), when it was noted that soldiers enlisted in the French
Army whose origins were from the Black, Red and White Volta basins (today known in
Burkina Faso as Mouhoun, Nazinon, and Nakambe), were significantly affected by
urinary schistosomiasis (Boiron & Koerber, 1947). In 1951, Deschiens listed the cercles
(provinces) of Ouagadougou, Bobo-Dioulasso, Kaya, Dedougou, Koudougou,
Tenkodogo, Togou and Ouahigouya as the most affected by urinary schistosomiasis and
remarked that intestinal schistosomiasis was much less widespread and more focalized
(Deschiens, 1951).
Already in 1957, however Marill argued that epidemiological information available was
sufficient to affirm that it was no longer appropriate to talk of" foci" of transmission for
urinary schistosomiasis, and that the whole territory constituted in fact a single, vast area
endemic for this infection (Marill, 1957):
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... « En tenant compte de l'ensemble des donnees que j'ai exposees ci-dessus, et
aussi de cette communaute de facture que determinent de memes conditions
geologiques, climatiques, hydrographiques, malacologiques et humaines, je pense
qu'il n'est plus desormais fonde de parler de «foyers» de bilharziose en Haute
Volta. Toute fa bande des plateaux voltatques, du Niger au Soudan [now Mali],
constitue trop evidemment une vaste trainee d'endemie bilharzienne, au sein de
laquelle certaines agglomerations humaines detiennent, si j'ose dire, le privilege
d'etre infectees pour fa totalite ou presque de leur population» ...
Several subsequent field studies have confirmed that no region of the country is free of
transmission of urinary schistosomiasis and that its prevalence and intensity of infection
is frequently high. An increasing gradient of prevalence and intensity of S. haematobium
infection exists from South to North, with the highest figures recorded in the
northernmost, arid Sahelian ecological area.
The prevalence and intensity of S. mansoni infection are much less important in the
opposite geographical gradient. Intestinal schistosomiasis is almost uniquely transmitted
in the southernmost Sudanese ecological area, except for the recent colonization of water
development schemes in other areas of the country (Wright, 1973; Poda & Traore, 2000;
Poda, Traore & Sondo, 2004).
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Within the vast, uninterrupted area of endemicity proposed by Marill (1957), the
phenomenon of clustering of cases of schistosomiasis around natural and artificial water
bodies has also been described as a key epidemiological characteristic. The majority of
the foci of schistosomiasis transmission is represented by rural villages located in
proximity of permanent or temporary ponds that serve as the community's principal
source of water for domestic chores. These villages can be considered the smallest
epidemiological risk units, whose aggregation constitutes the defined endemic area of
Burkina Faso (Marill, 1957; Poda & Traore, 2000; Poda, Traore & Sondo, 2004).
The risk represented by this natural scenario is further increased by the artificial risk
linked to the expansion or realization of water development schemes, such as those of
Sourou, Giedougou, Kou, Bagre, Ziga, Kompienga, and Moktedo, scattered throughout
the country and executed since the 1960s with the aim of increasing the surface of
agricultural land. It is estimated that more than 1,000 of such schemes exist nowadays in
Burkina Faso. Such water schemes have been shown to increase the risk of infection with
schistosomiasis, because they imply an expansion of the irrigated surface, a growth in the
density of the population and a rise in the density of the snail intermediate hosts that
found a new habitat favourable to their reproduction. Several authors have in fact
reported a significant increase in levels of urinary schistosomiasis in Burkinabe villages
surrounding artificial water bodies, as well as the establishment of local transmission foci
of intestinal schistosomiasis, not present before the development of the irrigation schemes.
It is generally believed that infections were introduced by migrant workers from the
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endemic areas in southern Burkina Faso in their search of better job opportunities (CNRS
& WHO, 1987; Poda & Traore, 2000; Poda, Traore & Sondo, 2004).
2.5.2 Schistosomiasis control in Burkina Faso
Prior to the present study, treatment interventions with praziquantel had only been
implemented sporadically in Burkina Faso. Treatment had been carried out especially in
areas around major irrigation schemes at Bagre, Sourou and Ziga, where schistosomiasis
was known to affect vast sectors of the population and represented a significant public
health problem. Treatment was also provided to individuals screened for epidemiological
assessments in the context of the implementation of field-based surveys (Poda, Traore &
Sondo, 2004; Seydou Toure, personal communication).
The National Schistosomiasis and Soil-Transmitted Helminthiasis Control Programme
(Programme National de Lutte contre fa Schistosomiase et les Vers Intestinaux, PNLSc)
was set up in June 2002 by the Ministry of Health (Ministere de la Sante) of Burkina
Faso to coordinate public health control activities against this group of infectious diseases.
The PNLSc was established under the Directorate for Disease Control (Direction de fa
Lutte contre fa Maladie, DLM), which is part of the Directorate-General of Health
(Direction Generale de fa Sante, DGS), under the overall coordination of the Secretariat
General (Secretariat General, SG) of the MoH. The PNLSc after its establishment in
2002, and up to in late 2003 had very limited financial resources - usually from the State
budget - which also significantly limited the magnitude of its disease control activities.
The staff of the PNLSc then comprised of the National coordinator (a medical doctor
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with specialization in public health) and a male nurse. Activities implemented by the
national schistosomiasis control programmes were somewhat complemented by local and
international NGOs which sometimes included praziquantel among the health package
distributed to populations in need (usually children). Overall, treatment was however
provided to small number of individuals in limited geographical areas only; as such
treatment activities were piecemeal and reflected the lack of a coordinating mechanism,
and of a unified effort to tackle schistosomiasis effectively.
Praziquantel was (and still is) in the national list of essential medicines of Burkina Faso,
and as such it was available at public and private pharmacies, from urban areas down to
village level, for individual case-management of individuals diagnosed with
schistosomiasis. The lack of diagnostic facilities at dispensary level meant however that
parasitological diagnosis could only be made at the district hospital level, which posed a
constraint to access to treatment for rural populations. In addition, access to treatment
was also somewhat limited by the fact that Burkina Faso was implementing the cost-
recovery policy recommended by the Bamako Initiative (WHO, 1988) whereby patients
needed to first purchase the drugs they require, even if mechanisms of compensation
existed at community level. In the case of schistosomiasis which afflicts mainly poor
rural populations the price, however small, is however usually too high for the affected
individuals. Treatment activities in the past were also limited by the fact that
schistosomiasis was not considered by rural populations a significant public health
problem or, in any case, a problem of lesser importance than other communicable
diseases prevalent in the country, such as, malaria.
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2.5.2.1 Schistosomiasis control implemented under the B&MGF/SCI-ICL grant
Large-scale control of schistosomiasis in Burkina Faso has its origins from a grant from
the Bill & Melinda Gates Foundation (B&MGF) to the Schistosomiasis Control Initiative
at Imperial College London (SCI-ICL) aimed at supporting disease control interventions
in sub-Saharan Africa (Garba et al., 2006; Kabatereine et al, 2006a). The aim of SCI-ICL
was to provide financial and technical assistance to six sub-Saharan African countries in
the development of sustainable national schistosomiasis control programmes, based on
the large-scale provision ofpraziquantel to school-age children over a period of five
years. A primary objective of these SCI-ICL-supported control programmes was to
achieve, and hence also demonstrate, a quantifiable reduction in schistosome-associated
morbidity as a consequence of such chemotherapeutic intervention (Fenwick & Webster,
2006). All Ministries of Health of sub-Saharan African countries endemic for
schistosomiasis were invited to apply to SCI-ICL for financial support of national
programmes. An international and independent panel was set up, with the aim of
selecting the six most valid national plans of action.
In order to launch and scale-up disease control activities of the PNLSc, the government
of Burkina Faso applied for financial and technical support through the SCI-ICL in 2003.
The application detailed a national plan of action against schistosomiasis and soil-
transmitted helminthiasis, which was selected by the independent panel set up by SCI-
ICL in November 2003. The PNLSc was officially launched on the 6th May, 2004 in
Ouahigouya, in northern Burkina Faso, by honourable Bedouma Alain Yoda, then
Minister of Health. The ceremony was attended by a large number of participants,
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including representative from international organizations, several local Governmental
officials and a significant delegation of the traditional authorities, led by His Majesty the
Naba Kiba, King ofYatenga (the traditional name of the region ofOuahigouya).
In operational terms, the MoH of Burkina Faso endorsed the WHO-recommended
strategy for control of schistosomiasis and opted for morbidity control through large-
scale preventive chemotherapy interventions. In the knowledge that old as well as recent
epidemiological data available showed that schistosomiasis was widespread across the
whole country and considering that a detailed mapping exercise would have required
assessing the transmission status in each single community, the MoH - with SCI-ICL's
agreement and support - decided to consider the entire national territory as endemic and
consequently to offer praziquantel free-of-charge to all school-age children (5 to 15 years)
living in Burkina Faso, irrespective of their place of residence.
Considering the frequent geographical overlapping of schistosomiasis and soil-
transmitted helminth infections, and based on the fact that WHO recommends co-
administration of praziquantel against schistosomiasis with albendazole (or mebendazole)
against soil-transmitted helminthiasis in areas where both infections are transmitted
(WHO, 2002 and 2006), the PNLSc decided to offer both drugs to any targeted individual.
This decision was also taken considering that - from logistic and operational points of
view - control of soil-transmitted helminth infections is similar to that of schistosomiasis
(both anthelminthic drugs are in oral, single-administration formulations, the same drug
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delivery channels and the same drug distributors can be used, the same population groups
are targeted). Co-administration of the two drugs to the same individuals, in areas where
both schistosomiasis and soil-transmitted helminthiasis are transmitted, is today a diffuse
practice in a number of countries in Africa and elsewhere.
The general WHO recommendations affirm that in areas where prevalence of infection
with any form of schistosomiasis, as assessed by parasitological methods is 2: 10%,
distribution of praziquantel to school-age children and other groups at high-risk should be
implemented at every 2 years, while where it is 2: 50 %, distribution of praziquantel
should be implemented at yearly intervals (WHO, 2006).
However, in spite of the data confirming that, on average, prevalence of schistosomiasis
was higher than 50%, the MoH of Burkina Paso decided to implement a policy whereby
treatment was assured to all the school-age children of the country once every two years.
This decision was taken at the beginning of activities and was based on previous small-
scale experiences with control of S. haematobium schistosomiasis in West African
countries which have epidemiological and ecological characteristics similar to those of
Burkina Paso (Campagne et al., 2001; Garba et al., 2004; Nsowah-Nuamah et al., 2004).
These investigations had in fact documented a longer-than-12-months-Iasting effect on
prevalence and intensity of S. haematobium infection after treatment with praziquantel.
Another consideration that supported this decision was that it appeared logistically too
heavy to cover the entire national territory every year for a country that had so far only
implemented small-scale treatment progress. The biannual calendar of re-treatment
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chosen by the MoR also appeared to be suitable to control morbidity due to other soil-
transmitted helminth infections, considering that the foci of transmission mainly showed
moderate prevalence and low intensity of infection.
A strong monitoring and evaluation component was however developed and implemented,
with the aim of closely assessing the impact ofthis national policy and, if necessary, re-
orientating the decision.
2.5.3 The structure of the health system in Burkina Faso
The health system in Burkina Faso consists of three different administrative and
operational levels. The current structure dates from 1993, when the health districts
(Districts Sanitaires) were instituted as the most decentralized units dedicated to
prevention and care [see Table 2 for acronyms and structure].
Overall, the SG is responsible for coordinating the national response to the different
health problems faced by the country. Disease control strategies are implemented through
the DRS, which are responsible for coordinating and supervising the execution of the
national health policies in each of the 13 regions of the country, through a series of
disease-specific programmes (among them, the PNLSc). The actual implementation of
disease control interventions is demanded to DS which supervise a dense network of
primary health care centres (CSPS). While the CHU, the CRR, the CM and the CMA are
mainly responsible for providing medical care through an individual case-management
approach and hospitalization when required, the CSPS is mainly responsible for
outpatient primary health care and for the implementation of public health activities such
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as vaccination campaigns and preventive chemotherapy interventions alike those against
schistosomiasis. CSPS are managed and supervised by the DS which is the real
operational unit of the entire system. Each DS is administered by a District Team (Equipe
Cadre de District) which coordinates public health as well as clinical practice within a
district. The catching population of a district in Burkina Faso is on average 220,000 while
that of the CSPS is 6,000 to 20,000. The health team based at each CSPS is usually
composed by a head nurse (Injirmier Chef de Paste), an assistant, and an obstetrician.
They supervise and coordinate a network of health workers which are volunteers that do
not have a formal medical background but have been trained in this regard by the CSPS
staff and are equipped with a basic medical kit. Usually two individuals per village are
identified as health workers: one (generally a man) is in charge of first-aid care, while the
other (generally a woman) is a midwife in charge of giving prenatal care to expecting
mothers, attending the birth of the infant, and providing postpartum care to the mother
and her infant (Foulon & Some, 2005).
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Table 2: The structure of the health system in Burkina Paso
Level Administrative structure Operational unit
National level Secretariat General du Centres Hospitaliers Universitaires
(n=l) Ministere de la Sante (SG) (CHU)
Regional level Directions Regionales de la Centres Hospitaliers Regionaux
(n=13) Sante (DRS) (CHR)
Centres Medicaux (CM) and
District level Districts Sanitaires (DS) Centres Medicaux avec Antenne
(n=55) Chirurgicale (CMA)
Centres de Sante et de Promotion
Sociale (CSPS)
Schistosomiasis campaign in Burkina Faso
,---------------------:=======1 Regionstargeledin
o October 2004October 2005
Benin
Pigure 1: Map of Burkina Paso showing areas targeted by the intervention in 2004 and
2005
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CHAPTER THREE
MATERIALS AND METHODS
3.1 The study area: Burkina Faso
Burkina Faso is a landlocked country in the heart of West Africa. It is located between
latitudes 9°20' and 15°3' north, and longitudes 2°20' and 5°3' west. It shares common
borders with six countries: Mali to the north and north-west, Niger to the east, Benin and
Togo to the south-east, and Ghana and Cote d'Ivoire to the south and south-west,
respectively. It occupies an area of274,200 krrr', of which 273,800 km2 are land and 400
km2 internal waters. It lies in the Sahel between the Sahara desert and the Gulf of Guinea,
south of the loop of the River Niger.
The central part of the country (85% of the country area) is covered by a peneplain, a
gentle undulating, almost featureless plain produced by fluvial erosion, called the plateau
Massi, which is 200 to 300 meters above the sea level. The rest of the country is covered
by two sandstone massifs (the plateau lateral de l'Ouest-Nord, around Bobo-Dioulasso
and Orodara. and the plateau lateral du Sud-Ouest, near the border with Togo and Benin).
These plateaux dominate the plains and are bordered by cliffs locally known with the
French term ofJalaises which may be up to 150 meters high. The highest peak in Burkina
Faso (Mount Tenakourou) is 749 meters high and is located in the plateau lateral de
I 'Ouest -Nord.
As early as the 15th century Burkina Faso possessed a well-structured and organised
social and political entity which consisted of five Mossi kingdoms and a supreme chief,
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the Mogho-Naba, (the Mossi emperor in Moore language). In 1896, the Pays Massi,
together with other adjoining territories, combined to form the French colony called
Haute Volta (Upper-Volta, because of its location upstream of the Volta River which
flows southwards into Ghana). In 1932 the colony was partitioned into Mali, Niger and
Cote d'lvoire and thus the Mossi Kingdom disappeared as a single entity. It did not
recover its autonomy nor its borders until 1947. Upper-Volta gained independence as a
republic on August 5, 1960, and on August 4,1984, the Republic of Upper-Volta was
given the name "Burkina Faso", which means "the Land of Honest People", by late
President Thomas Sankara.
Burkina Faso has an important hydrographic network of three main water basins:
• the Volta basin (178,000 km"), which covers the central part of the country and is
fed by rivers Mouhoun, Nakarnbe and Nazinon;
• the Cornoe basin (1,700 km"), which covers the south-west part of the country and
is fed by the Cornoe river and its affluents R. Leraba and R. Yanon; and
• the Niger basin (79,000 km-), which covers the westernmost and easternmost
portions of the country and is fed by several affluents of R. Niger namely the
Banifing in the west, and the Bali, Garouol, Sirba, Gouroubi, and Tapoa in the
east.
In general, most of the watercourses are seasonal and among the large rivers, only the
Mouhoun (formerly Black Volta), the Comoe and the Pendjari are perennial. Smaller
permanent streams are found in the south-western part of the country. Many small and
large pools and ponds exist, created by the several small depressions that are scattered
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throughout the country. These pools and ponds may be temporary (i.e. present only
during the rainy season), or perennial (i.e. existing throughout the year). Additionally, a
significant number of water development schemes and dams have been built over the last
50 years for agricultural and domestic purposes.
Burkina Faso has a typical inter-tropical climate, with two alternating seasons, a long dry
season from October to April in the North and from November to May in the South, and
the shorter rainy season from May to September in the North and June to October in the
South. The country can be broadly divided from North to South into three ecological
areas: the Sahelian (sandy soil, steppes, grassy and bushy savannah; average yearly
rainfall totals < 650 mm), the Sahelo-Sudanese or North Sudanese (bushy and wooded
savanna; average yearly rainfall totals between 650 and 1,000 mm), and the Sudanese or
South Sudanese (bushy savanna and forest; average yearly rainfall totals> 1,000 mm).
The total precipitation for the whole country is low averaging between 650mm in the
Sahel and a little higher than 1,000mm in the Sudanese savanna in the south.
The country is divided into 13 administrative regions (Regions) and each region is
divided into districts which in 2003 numbered 55. In 2004 there were approximately 3.65
million school-age children (5-15 years old) out of a total of nearly 13 million inhabitants
(Ministere de la Sante, 2004 & 2005). The population is also widely dispersed over the
territory, with a high percentage of people living in rural villages. The 2003 population
data show that the urban population was just 17.8% of the total (UNDESA, 2004).
Burkina Faso has a low school enrolment rate, the primary school net enrolment rate in
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2002-2003, the years with most recent data available at the time of the implementation of
the activities, was 36% (UNESCO, 2006).
3.1.1 The target population
The target population was defined as the primary school-age population living in the IUs
where preventive chemotherapy was to be implemented. In the four IUs targeted in 2004,
the target population was calculated to be 1,115,336 individuals and 2,543,918
individuals for the 9 IUs targeted in 2005. The figures for each IU were extrapolated from
the official data generated for these years by the Statistics Division of the MoH
(Ministere de la Sante, 2004 & 2005). The MoH data were based on the latest
information available from a national census conducted in 1996 and underwent an
updating process that took into account the yearly population growth rates, disaggregated
according to region and district so to reflect as much as possible the different
demographic trends across the country and to allow for a true representation of the
population living in each IU. The mentioned updating process is carried out on a regular
basis by the MoH, mainly for estimation of target population and calculation of coverage
rates for vaccination purposes, and is subject to a constant feedback by officers working
in the Expanded Programme for Immunization (EPI), such that figures are considered
highly reliable (Seydou Toure, personal communication).
Target population within a defined area was further broken down in school-enrolled and
non school-enrolled. The estimation of the school-enrolled population was based on
summary enrolment data of the Ministry of Education, which were integrated with the
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data from school registers kept by headmasters where necessary and revised by the heads
of the relevant CSPS, in collaboration with Ministry of Education's staff. The non school-
enrolled population was calculated by subtracting the school-enrolled population data
from the updated census data. All of these were performed before the implementation of
the control activities
3.2 Description of programme activities
The intervention was designed such that the entire school-age population in the country
was treated once with praziquantel and albendazole within two years. The adopted
operational approach was based on the implementation of a two-phase treatment
programme. The first phase was to be implemented in October 2004 and the second in
October 2005, so that within 18 months from the start and 12 months after the first phase,
each eligible child would have received its first praziquantel treatment..
The first phase of the programme was undertaken in four regions, namely Boucle du
Mouhoun, Nord, Sahel and Sud-Ouest, which were identified as the most endemic and
with the highest risk of morbidity in Burkina Faso and therefore in most need of
treatment. The target population in the four regions was estimated at over 1.1 million
school-age children.
The second phase took place in October 2005 and covered the remaining nine regions of
the country with a target population estimated at over 2.5 million school-age children. As
planned, the whole national territory was therefore covered in the space of one year from
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the commencement of treatment activities. A whole week in October of 2004 and 2005
was dedicated solely to the schistosomiasis treatment campaign by the MoH. During
these periods the entire MoH staff at regional, district and sub-district (CSPS) levels were
mobilized to implement the intervention activities. Obviously provision was made for
guaranteeing essential health services throughout the country, as needed.
Figure 1 shows the geographical distribution of areas targeted in 2004 and 2005.
Both passive and active approaches to treatment were employed. The "passive" strategy
targeted children in school (considered as aggregation points), and the "active" strategy
(the community delivery channel) involved the community drug distributors seeking out
children not in school and more often living in remote villages or hamlets in the bush.
The two delivery channels were complementary measures aimed at achieving the highest
possible coverage among the target population.
3.2.1 Implementation units
Each of the 13 DRS of the country was defined as an implementation unit (IU). All IUs
were considered endemic for schistosomiasis, and therefore all primary school-age
children considered eligible for treatment. Within the framework of the strategy
developed by the PNLSc each IU was operationally autonomous in terms of utilization of
resources and the implementation of the activities including treatment.
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3.2.2 Procurement and distribution of material
Drugs were sourced from both the local and international markets. Preference however
was given to procuring medicines through the Burkina Faso National Essential Generic
Drugs Purchase Company (Centrale d'Achat des Medicaments Essentiels Generiques,
CAME G) when quoted prices were competitive. This was preferred in order to establish a
mechanism that would promote sustainability of drug procurement activities at country
level. When quotations provided by the CAMEG were not competitive, that is, when they
were sensibly higher than the prevalent average cost for large quantities in the
international market, drugs were purchased through the Imperial College London
procurement services, following an open tender process.
A total of 8,721,731 tablets of praziquantel were acquired for the programme out of
which three million were donated by international agencies through the SCI-ICL. Drugs
were ordered about six months prior to the implementation of each phase of the
intervention. The drugs were first stored on the PNLSc's premises in the capital
Ouagadougou and were subsequently transported by road to DRS warehouses in the
regional capitals at Dedougou (Boucle du Mouhoun DRS), Ouahigouya (Nord DRS),
Dori (Sahel DRS), and Gaoua (Sud-Ouest DRS). The district health officers collected
their allocation from these warehouses and the CSPS-based staff collected drugs from the
nearest health' district office to their respective CSPS which was usually by motorcycles.
The quantity of tablets allocated for each region, district and CSPS were calculated based
on the available national census data, which were adjusted upwards to take into account
the disaggregated yearly population growth rates. This procedure had been applied and
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validated in previous immunization campaigns in the country (Ministere de la Sante,
2004 & 2005).
Equipment including wooden dose poles for administration of praziquantel with threshold
levels clearly marked for easy reference were all ordered and in place four months prior
to implementation of programme activities. All other material including data collection
forms etc were also made available within this time frame.
3.2.3 Communication strategy for social mobilization
Strategic communication activities were launched at different levels with the ultimate aim
of creating the awareness to achieve highest possible compliance. A famous personality
Mr Athanase Raoul Moussiane who is a traditional wrestler and nicknamed "le Taureau
du Nayala" (translated as the "Bull of Nay ala") was recruited to star in a television
advertisement which was broadcast on the national television channel Radio Television
Burkinabe (RTB) in French and in seven different local languages. The television
advertisement emphasized the opportunity and benefits offered by the programme and the
need for engagement and commitment by all to achieve schistosomiasis control in
Burkina Faso. The television spot also conveyed other messages that informed the
population in the targeted areas on the dates of drug administration. Similar messages
were also broadcast on national and local radio stations. Public criers and religious bodies
(e.g. Muslim muezzin and Catholic priests), as well as traditional authorities (e.g. village
heads) were also used to inform populations, down to the smallest and the most isolated
communities.
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3.2.4 Staffing and remunerations
CSPS teams were responsible for the treatment of children at the dispensary premises and
also for organizing, coordinating and mobilizing school-masters and teachers for
treatment in schools, as well as of community drug distributors to reach the non-enrolled
children. Each CSPS team irrespective of its size was paid 10 FCF A (equivalent to
approximately US$ 0.018) per target child in the respective catchment area. School
teachers however were not remunerated as taking care of the health of their pupils is
considered by the Governmental authorities of Burkina Faso as an institutional duty
within the framework of the national school-health activities. Their active participation in
the campaign (and in similar public health interventions implemented for other reasons)
was therefore regarded as part of their routine activities.
Community drug distributors were remunerated by their own communities through the
Comites de Gestion (management committees) in charge of establishing health policies
and drug priorities at CSPS level. The total number of community drug distributors
involved was estimated at 16,000, and their average remuneration was 1,000 FCFA
(US$ 1.8) per person for the entire duration of the campaign.
Each district contributed to the campaign from its health budgets by providing funds for
the fuel for the motorbikes or scooters to reach the remote communities. Such
contribution was calculated based on a 15 km journey (on average) per community drug
distributor at a cost of 40 FCF A (US$ 0.073) per km.
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3.2.5 Training of staff
Meetings and workshops to plan the modalities of the treatment campaign were held at
the regional and district levels, and were attended by both MoH and MoE staff and
partners such as local and international non-governmental organizations (NGOs)
involved in control of schistosomiasis and soil-transmitted helminth infections in Burkina
Faso.
Several training sessions for health workers, community drug distributors and school
teachers were also conducted. The training provided information on the epidemiology of
schistosomiasis and soil-transmitted helminthiasis, the benefits of treatment, dose
determination, the management and reporting of adverse events, the modalities of filling
and keeping treatment records and on calculation of coverage, as well as on the exclusion
criterion for treatment. These were organized at the regional, district and dispensary
levels through a cascading process, in which senior health and education officers in
charge of each district were first trained at regional level, they in turn trained sub-district
level officers (heads of CSPS and school-masters) and in turn sub-district level officers
were in charge of training community drug distributors and school teachers. A total of
approximately 22,000 persons were trained throughout the country, before the first and
the second phase of the campaign, as appropriate. Such activities were facilitated by the
use of training manuals, teaching aids and presentations developed by the PNLSc
coordination team.
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3.2.6 Drug delivery channels
Treatment was carried out in schools and in communities. Wherever possible, the school
delivery channel was used with the advantage that the teachers could be fully involved in
administration of medicines to their own pupils, thus relieving the health staff from such
a task. For all other children not attending school, community delivery channels
involving both mobile and fixed treatment units were used.
In both the schools and the communities, activities were organized and supervised by the
MoH staff based at each CSPS (composed of a head of the centre who is a registered
nurse and a number of health workers), with the aim of establishing a calendar, setting
tasks and priorities, as well as that of mobilizing, co-ordinating and supervising teachers
and community drug distributors in order to streamline the intervention and avoid
overlapping of responsibilities and targets.
3.2.7 Administration of praziquantel
The correct dose ofpraziquantel (600 mg tablet) using the WHO dose-pole (Montresor et
al., 2001a; WHO, 2006) was calculated as follows: 94-109 em (1 tablet); 110-124 ern (1
Yz tablets); 125-137 em (2 tablets); 138-149 ern (2 Yz tablets); 150-159 em (3 tablets);
160-177 em (4 tablets); ~ 178 em (5 tablets).
Each treated child also received a single tablet of albendazole (400 mg). Directly-
observed treatment (DOT) was implemented i.e. the actual swallowing of the tablets by
children was directly observed by those administering the drugs. The aim was to ensure
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allowing for correct calculation of the number of individuals that received treatment, and
finally for establishing the occurrence of adverse events as due to the treatment.
3.2.7.1 Inclusion and exclusion criteria
The entire primary school-age population of Burkina Faso was considered eligible for
treatment irrespective of their school enrolment status.
As per WHO recommendations, seriously ill individuals were excluded from treatment
(WHO, 2006). Children suffering from conditions requiring medical attention were
referred to the nearest CSPS (or higher level as appropriate). Health staff was also
responsible for administering praziquantel to such individual after ascertainment of full
recovery. In addition, the detection of pregnancy in the first trimester was also considered
an exclusion criterion for albendazole. Such status was detected based on recall of the last
menstrual period, a method suggested by Chippaux et al. (1995) and subsequently
recommended by WHO (2006) as the most appropriate. The same measure as for ill
individuals was applied to pregnant women in the first trimester with regard to referral to
health centres and deferred treatment with praziquantel.
3.2.8 Reporting and management of adverse events
A system was developed to detect and manage adverse events following treatment. This
involved training both school teachers and community drug distributors on how to deal
with adverse events and how to assure children and their families of the minor and
transient nature of such events. In communities, all children were asked to wait a few
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minutes at the treatment point after swallowing the tablets so as to allow the community
drug distributor to monitor the occurrence of any unusual event. In schools, treatment
took place inside the classrooms and children were asked not to leave, for the same
reason. Those experiencing any discomposure after taking the drug were looked after by
the teachers or the community drug distributors. In case side-effects could not be
managed by the first-line personnel, children were referred to the nearest CSPS for
medical care. In order to closely follow adverse events, relatives or guardians requesting
the drug to treat children or relatives outside the treatment points were refused, unless
when absolutely necessary.
3.2.9 Data collection and management: performance indicators
The numbers of individual treated during the two phases of the campaign were recorded
on standardized forms set in simple tabular format (Appendix II and III). The data were
collected by the individual responsible for treatment i.e. teachers and community drug
distributors, who were trained on appropriate modalities of form filling. In addition to the
numbers treated, other key demographic data including age and gender were recorded for
each treated individual so as to allow further analysis and interpretation of results. As a
result, coverage was calculated from actual data collected at all treatment sites and
therefore no extrapolation or generalization of the sentinel sites' data occurred.
The forms were modified from those used by MoR staff for recording and collecting
coverage data during immunization interventions by the PNLSc. Specific forms were
designed for each of the delivery channel, i.e. school and community, and were collected,
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transmitted and were kept separately in order to allow for their specific performance
assessment. The data then were progressively aggregated into summary forms at sub-
district, district and regional level, which were considered data collation points.
Eventually all data were transmitted to the highest level in the hierarchy, i.e. the PNLSc
coordination team, that served as data analysis point and was responsible for data
cleaning and for production of the relevant reports. The exercises of data collation,
cleaning and publication were characterized by a close working collaboration between
the central and the peripheral units of the MoH such that a constant feed-back and cross-
check process was organized in order to generate and report the most accurate
information.
Cost data were obtained from the records of the financial expenditures and allocations
made by the PNLSc, or made by SCI-ICL on behalf of the PNLSc (as is the case, for
example, of drug procurement).
3.2.10 Data collection and management: impact indicators
At baseline and follow-up, information on each child participating in the survey was
recorded on a standardized form (Appendix I). Information included demographic,
anthropometric, infection and morbidity data. Field activities inherent to monitoring and
evaluation of the programme's impact were carried out by a PNLSc central team which
consisted of the head of the PNLSc itself, one epidemiologist, two nurses, three
laboratory technicians and other support staff (drivers). The team however co-opted
laboratory technicians based at each area being the DRS or district level into its activities
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of supervising the processes and the modalities of the intervention. The team also
conducted on-the-job refresher training course before the actual implementation of the
survey with the aim of standardizing laboratory practices; Occasionally the team was
assisted by representatives from technical collaborating institutions particularly the NGO
Reseau Intenational Schistosomoses, Environnement, Amenagement et Lutte (RISEAL).
I also provided technical assistance to the team in my official capacity as the SCI-ICL
officer responsible for Burkina Faso.
3. 3 Assessment of programme performance
Performance in this study was defined as the measurement of activities carried out in the
context ofa defined intervention (Brooker et al., 2004). To assess the performance of the
intervention, two main indicators, the coverage and the costs related to implementation of
the activities, were used.
3.3.1 Coverage
The WHO recommends three different coverage parameters for monitoring and
evaluating preventive chemotherapy interventions. These are geographical coverage,
epidemiological coverage, and programme coverage (WHO, 2010b). These parameters
were determined by this study using the formulae below:
Geographical coverage Number oj IUs where PC is implemented
Number oj IUs eligible for PC
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Epidemiological coverage Number of individuals treated
Number of individuals eligible for PC
Programme coverage Number of individuals treated
Number of individuals targeted by PC
Where IU is implementation unit and PC is preventive chemotherapy (i.e. treatment).
3.3.2 Costs
The cost of each activity directly related to the implementation of the campaign including
delivery and drug costs to finally arrive at the overall costs and cost per treated person
were determined. This cost-analysis includes any financial transaction (cash expenditure)
related to the implementation of both phases at each administrative level and took into
account activities supported by the national budget (through to the district budget), SCI-
. ICL, budget and community contributions. Costs of procured drugs, their delivery up to
the MoH's premises in Ouagadougou to the treatment points and also for donated drugs
were priced at the prevailing market costs.
In contrast, this cost-analysis did not take into account economic costs such as unpaid
days oflabour for individuals involved in the campaign (such as teachers), or other costs
related to the regular functioning of the PNLSc such as salaries which were covered by
the national budget. It is therefore not meant to be an analysis of the costs of the
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functioning of a national control programme (the PNLSc in this case), but only an
analysis of the costs related to the implementation of the preventive chemotherapy
intervention implemented in 2004 and 2005. The main justification for this approach is to
allow comparability with similar experiences carried out in other countries. Moreover
acquiring such data would have required a huge logistic support which could not have
been done with the resources available for the study.
In order to increase the robustness of the results, sensitivity analysis was performed with
the aim of assessing how cost estimates would vary in function of the change of
determined variables. Chosen variables were: cost of praziquantel, remuneration of MoH
staff and of community drug distributors, and remuneration of teachers. For cost of
praziquantel, the highest and lowest prices currently available on the market were taken
into account (International Drug Price Indicator Guide, 2011); remuneration of MoH staff
and community drug distributors was doubled in the hypothesis that their demand for
remuneration will increase in the future; remuneration of teachers was introduced into the
model in the hypothesis that they are remunerated as equally as community drug
distributors (1,000 FCF A per person for the entire duration of the campaign).
All cost calculations were made in US dollars (US$). Costs of purchase, insurance and
freight of drugs from the manufacturers to Ouagadougou's airport were paid in US$ and
the actual figures were used in the analysis. The other costs were in Francs de fa
Communaute Financiere Africaine (FCFA) and were converted to US$ at the rate of
FCF A 550 = US$ 1. Cost and expenses data were then allocated to their respective
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activity domains as follows: (a) drugs; (b) remuneration for drug distribution staff
(excluding teachers that were not remunerated); (c) coordination, planning and
supervision; (d) training; (e) transportation and logistics; (f) social mobilization; (g)
capital equipment. Delivery costs were defined as the sum of all costs minus the drug
costs, i.e. activities b, c, d, e, f, and g. In terms of allocation, the costs and expenditures
made at the four administrative levels, national, region, district and CSPS were similarly
allocated.
In order to obtain costs per treated child, delivery costs were divided by the number of
children reached by the campaign. The breakdown of the costs included:
• Delivery costs per child treated (total delivery costs / number of children treated);
• Recurrent delivery costs per child treated i.e. total delivery costs less the capital
equipment costs and training costs / number of children treated;
• Drug costs per treated child (total drug costs / number of children treated); and
• Total costs per child treated: total costs of the campaign (delivery + drugs) /
number of children treated
All these costs were further broken down into costs per child treated at school and per
child treated in the community, so as to allow comparison between the two delivery
channels to be made.
Although the period officially dedicated to the campaign was one week (18-24 October
2004 and 17-23 October 2005), a few scattered drug distribution activities continued over
a few days in those villages or schools that could not have been properly targeted during
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enrolled schoolchildren were also recruited for cross-sectional studies, during each
follow-up of cohorts, with the aim of assessing the quality of the community-based
interventions. These newly enrolled children were expected to have been treated through
the community-based drug delivery channel having reached their s" and sixth birthdays
while still out of school. An additional cross-sectional survey was carried out among age-
and gender-matched schoolchildren during the 2nd follow-up with the aim of validating
the longitudinal data, in other words, to prove that the cohorts did not receive any
preferential treatment.
3.4.1 Impact assessment using longitudinal survey
The sample size for the study was estimated based on assumptions of an expected
reduction of 70% in mean intensity for S. haematobium and yearly drop-out rate of 40%
over the 2-year period using the EpiSchisto software tool (Schools & Health, 2010). The
40% yearly drop-out rate was based on previous personal experience of MoH staff that
had been engaged in similar studies in Burkina Faso (Seydou Toure, personal
communication). The children were recruited from 16 sentinel schools randomly selected
from all the national accredited primary schools including Islamic schools (called
medersa) and mixed lay-religious institutions (Franco-arabe schools) in the four Regions
targeted under phase 1 in 2004 (i.e. Boucle du Mouhoun, Nord, Sahel, and Sud-Ouest).
Sentinel schools were originally 17, but one of them has been excluded from the present
analysis as no cases of S. haematobium infection had been found among the children
surveyed there.
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the campaign due to difficulty of access, insufficient number of tablets allocated, or
movement of nomadic populations. These activities were also taken into account in the
calculations of coverage and costs, even though they were usually integrated into other
routine health activities carried out at the district and CSPS levels in order to avoid extra
costs.
3.4 Assessment of programme impact
In public health practice, impact is defined as the health benefit of a defined intervention
(Brooker et al., 2004). For this study the monitoring and evaluation of the health impact
was designed to use both longitudinal follow up of cohorts and cross-sectional studies to
assess the impact of the programme on infection and morbidity. For the longitudinal
study component the indicators were measured at baseline i.e. before the commencement
of treatment, in cohorts of children representative of the target population, and were
subsequently followed up over a period of time. Employed infection indicators were
prevalence of infection, intensity of infection, and proportion of heavy-intensity
infections with S. haematobium. The morbidity indicators used were mean haemoglobin
concentration, prevalence of anaemia, prevalence of microhaematuria, prevalence of
thinness or wasting, and prevalence of shortness or stunting.
For logistic reasons related to the ease of tracking the children participating in the surveys,
the longitudinal studies targeted schoolchildren (i.e. children attending schools). As a
consequence, this exercise could only provide information on the quality of the school-
based delivery channel. To take care of this bias, seven-year-old, first-year, newly-
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Within each school, approximately 180 children were selected randomly from the 6-14
year age-group, with approximately equal numbers (20) of children in each of the nine
different age-groups with 10 each of boys and girls within each age group. Children aged
6-14 years were selected as the standard age-group for monitoring and evaluation
purposes across the six countries supported by SCI-IeL, with the aim of comparing the
impact produced by schistosomiasis control activities in different settings; consequently,
this age-group was adopted in Burkina Faso as well, in spite of the fact that the
population targeted for treatment also included. 5-year-old children. In total, a cohort of
1727 schoolchildren was selected at baseline from 3 schools in Boucle du Mouhoun, 5 in
Nord, 6 in the Sahel, and 2 in the Sud-Ouest [Figure 2]. All the children were examined
to obtain the parasitological and morbidity information outlined in section 3.4 of the
thesis above. These children were examined at baseline and followed up twice after
treatment, one year post-treatment in 2005 and two years post-treatment in 2006.
3.4.2 Assessment of community-based interventions using cross-sectional
survey of new-enrolled
For this study component, seven-year-old first-year, newly enrolled pupils, approximately
10 boys and 10 girls, were randomly selected from each sentinel school and examined to
obtain parasitological infection indicators. These children were expected to have been
targeted for treatment through the community-based drug delivery channel (targeting
from the s" birthday onwards) before being enrolled in schools. Infection status in these
children therefore was supposed to represent the quality of community-based treatment.
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·.OU';;:;::;I
o Ouagadougou
• Koudougou
100 0 100 200 Kilometer.
~=--~~~~liiiiiiiiiiiiiii;i
D Sllhdilln ana D Sahdo-SlHlaJtt~tan.l DSll.laJltH ana .. Senrinel s(hools
Figure 2: Geographical distribution of the sentinel schools - including the one in which
no S. haematobium infection was found (Nabere) - within the ecological areas of Burkina
Faso
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3.4.3 Cross-sectional survey of school children for cohort data validation
(school control group)
The cross-sectional component of the survey was conducted in 2006 during the second
follow-up only. For this survey, schoolchildren were randomly selected in each of the 16
sentinel schools among those who were not participating in the cohort studies and
examined to obtain parasitological infection indicators. The parasitological indicators of
such individuals were then compared with those of the children in the original cohort,
following an age and gender matching process. The purpose of this cross-sectional study
component was to serve as a control group with the dual aim of confirming the quality of
the school-based intervention and validating the cohort data, or, in other words, to
demonstrate that no preferential treatment had been given to children who formed the
cohorts.
3.4.4 Calendar of baseline and follow-up activities
Each of the 16 sentinel schools was visited three times during the study period at baseline,
first and second follow-ups.
The baseline data were collected months before the implementation of the interventions
in schools. For reasons of school calendars and in order to avoid conducting surveys
during the rainy season (May to October), the visits were made between February and
April 2004. At baseline, both infection and morbidity indicators were collected from all
children participating in the longitudinal survey. None of the children were treated at this
time in spite of the violation of the "no survey without service" rule. This decision was
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considered as ethically acceptable in view of the consideration that the large-scale
implementation of praziquantel would be treated within a few months after the survey in
October 2004.
The first follow-up was carried out approximately one year after the intervention, that is,
during November and December 2005. At 1st follow-up, both infection and morbidity
data were obtained from children participating in the cohort study, and infection data only
from the newly enrolled pupils recruited for the cross-sectional survey.
The second follow-up was carried out approximately two years after the intervention, that
is, in November-December 2006. For this follow-up, only infection data were collected
from children participating in the cohort study, from newly-enrolled children recruited for
assessment of community-based delivery, and from children participating in the school
control group.
3.4.5 Drop-outs
Drop-outs were defined as those children recruited at baseline who could not be traced
during the first follow-up and those who were present during the first follow-up but
absent during the second follow-up. This means that drop-outs were absent from school
for both days spent in each sentinel site by the surveying team at each follow-up
appointment, and could not be traced in communities neighbouring the school. Drop-out
children had usually moved with their families to different domiciles, or had definitely
abandoned the school.
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Baseline Treatment 1st follow-up 2nd follow-up
T T T T
.---- r- r-
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CJ) CJ)
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Longitudinal 0....... .0...... c:< Longitudinal:::s :::s ..
CD CD ~ CD II""""
survey :E :E < survey
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Feb to Apr October Nov-Dec Nov-Dec
2004 2004 2005 2006
Time
Figure 3: Chronological framework of activities aimed at assessing programme impact
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3.5 Description of methods
3.5.1 Infection indicators
3.5.1.1 Diagnosis of urinary schistosomiasis
Diagnosis of urinary schistosomiasis was carried out by detecting S. haematobium eggs
in urine samples by microscopy using the filtration method of Plouvier, Leroy & Collette
(1975). Urine specimens were collected either late morning or very early afternoon
(usually between 10:00h and 13:00h). 10 ml of urine were filtered through a 13mm0
nylon filter (Millipore Isopore®, pore size lZum), and the number of eggs counted under
a microscope. For urine ofless than 10 ml, the volumes were measured before filtration
and the number of eggs per 10 ml consequently calculated. For each infected children,
intensity of infection was noted. The intensity of S. haematobium infection was expressed
as the number of eggs per 10 mL of urine (eggsllO ml). The prevalence expressed as the
percent of infected cases, the arithmetic mean of intensity of infection, as well as the
proportion of heavy-intensity infections were then calculated. Heavy-intensity infections
were defined as those equivalent to or exceeding 50 eggs/l0 ml of urine (WHO, 2002).
3.5.1.2 Diagnosis of parasitic infections other than urinary schistosomiasis
These studies were performed in order to assess co-endemicity of other helminth
infections at the sentinel sites. This involved stool examination to diagnose intestinal
schistosomiasis caused by S. mansoni and soil-transmitted helminth infections with
Ascaris lumbricoides, Trichuris trichiura and hookworm (Ancylostoma duodenale and
Necator americanus). A stool sample was collected and the Kato-Katz thick smear
technique (Kato & Miura, 1954; Katz, Chaves & Pellegrino, 1972; WHO, 1994) used to
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process the samples by microscopy. For each specimen duplicate slides were prepared
and examined on the same day. The parasites' eggs were counted and the intensity of
infection was expressed as eggs per gram of faeces (epg). From the results obtained the
arithmetic mean of the two individual slide counts were calculated. Due to logistical
reasons approximately half of cohort children were randomly selected for the stool
examination during the baseline survey.
3.5.2 Morbidity indicators
3.5.2.1 Haemoglobin status and prevalence of anaemia
Blood samples were obtained from each individual by using the finger-prick capillary
collection method and the haemoglobin concentration (grams/litre of blood) determined
using a Hemocue® digital photometer (Hemocue AB, Angelholm, Sweden). This
technique is considered the gold standard in field work activities for determination of
haemoglobin concentration (Gies et al., 2003). From these values the anaemic status of
each individual was established based on recommended thresholds defined by WHO
[Table 3]. The mean Hb concentration was calculated, as appropriate and as well as the
prevalence of anaemia in the surveyed population.
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Table 3: Haemoglobin levels below which an individual is considered anaemic
(UNICEF/UNU/WHO, 2001)
Age or gender group Haemoglobin
(gramsllitre)
Children 6 months to 59 months 110
Children 5-11 years 115
Children 12-14 years 120
Non-pregnant women (above 15 years of age) 130
Men (above 15 years of age) 130
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3.5.2.2 Detection of microhaematuria
To determine the presence and extent of micro haem aturi a (invisible presence of blood in
urine), all urine specimens were tested for presence of detectable blood by using urine
reagent strips (Hemastix®, Bayer, Germany), a test increasingly used in the monitoring
and evaluation of schistosomiasis control programmes in endemic settings (French et al.,
2007). The results were recorded semi-quantitatively as follows: negative, trace, weakly
positive (+), moderately positive (+ +), and highly positive (+ + +). The prevalence of
each class of microhaematuria was consequently calculated from the results obtained.
3.5.2.3 Determination of nutritional status
Both height-for-age z score (HAZ) and body-mass-index z score (BMIZ) which are
measures of nutritional status and growth (Gibson, 1990; WHO, 1995) were determined
for each child. HAZ assesses long-term growth and nutritional status; a low HAZ reflects
the failure to grow adequately in height relatively to age, thus resulting in shortness or
stunting, which is considered as the cumulated expression of protracted exposure to an
inadequate nutrition balance; stunting was defined as a HAZ less than -2 SD. The BMIZ
assesses recent nutritional status; a low BMIZ reflects low weight relative to height, thus
resulting in thinness or wasting which is defined as wasting ifBMIZ was less than -2 SD.
The heights and weights of all the children were measured using height poles and
electronic balances. The measurements were taken in the morning; children were barefoot,
and wore only light indoor clothing.
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The z scores for both nutritional indexes were calculated based on Centre for Disease
Control reference values (National Center for Health Statistics, 2000) using EpiInfo
(version 2000; US Centers for Disease Control and Prevention) (Ogden et al., 2002).
3.5.3 Data analysis
Pre-treatment information obtained from the original cohort served as the baseline data.
All data were analysed using SAS software version 9.1 (SAS Institute, Cary, NC, United
States of America). 95% Confidence Intervals (CIs) were obtained together with
summary statistics. Prevalence and arithmetic means of intensity of infections were
compared for all the years of interest, as appropriate (Fulford, 1994; Montresor, 2007).
Nonparametric-tests were used as no assumptions were made about the distribution of
schistosomiasis egg counts -- the indicator used to calculate prevalence and intensity of
infection - among the sampled population. 1'11i3was justifiedby the consideration that
schistosomes. as it is the case of most helminth species (Anderson & May, 1991), are
over-dispersed or aggregated in the human susceptible population. In practical terms. this
fact implies that many hosts harbour few parasites whereas few hosts harbour many
parasites (Shire 20(7), thus configuring a. non-Gaussian distribution. When analyzing
data relative to the longitudinal cohort, therefore generated by two measurements of the
same individuals under different conditions and at different times, the McNemars test
was used for comparing differences in prevalence of infection (binomial data subject to
only two outcomes: positive or negative), and the Wilcoxon test J()I' comparing
differences in mean intensity of injection (rank or score value). When comparing data
from the other study components, thus generated by measurements of two different
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groups of individuals, the X2(chi-square) test was used for prevalences of infection, and
the Kruskal- Wallis test for mean intensities of infection (Motulsky, 1995).
3.6 Ethical considerations
All activities described in this thesis were carried out in the framework of the monitoring
and evaluation component of the PNLSc. All the research activities described in the
thesis received ethical clearance under the ambit of the SCI-ICL, from the National
Health System Local Research Ethics Committee of St Mary's Hospital, London, United
Kingdom. Approval was also sought and obtained from the Ethical Committee of the
Ministry of Health of Burkina Faso. The activities carried out at sentinel schools were
carefully explained to local Governmental authorities from the health and education
sectors as well as to identified representatives of each community (e.g. traditional village
authorities) before their implementation. Written informed consent to participate in the
surveys was obtained from head teachers at each school visited. The parents or guardians,
or representatives of each child were equally informed and their permission sought.
Children unwilling to participate were never forced to take part and no punitive measures
were threatened. All activities described in this thesis were carried out by informed and
trained personnel who were all staff of the MoH, Burkina Faso with the exception of the
investigator.
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CHAPTER FOUR
RESULTS
A total of 1,027,007 school-age children (5-15 years old) were treated during the first
phase of the campaign in October 2004 and 2,295,557 during the second phase in
October 2005. Thus the overall total number of children treated during the intervention
was 3,322,564. Of these 3,322,564 treated children 1,324,388 (39.9%) were reached
through the school delivery channel and 1,998,176 (60.1%) through the community
channel. Also, of the total children treated 1,713, 842 (51.6%) were males and 1,608,722
(48.4%) were females [Table 4].
4.1 Performance
4.1.1 Coverage
The detailed results of the coverage obtained are given in Tables 4 and 5. Briefly, an
overall geographical coverage of 100% was achieved by the end of the two years of the
programme's implementation. In the first year four of the 13 eligible Regions (30.8%)
were covered and the remaining nine (69.2%) were covered during the second phase.
Of the target population of 3,659,254 persons 3,322,564 were treated at the end of the
intervention which translates into an epidemiological coverage of 90.8%. During the first
phase the programme coverage achieved was 92.1% having treated 1,027,007 out of the
estimated target of 1,115,336 eligible children in the four targeted Regions. The
comparative programme coverage achieved by the phase two of the intervention was
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slightly lower at 90.2% (2,295,557 were treated out 0[2,543,918 eligible in the nine
targeted Regions).
Overall programme coverage was 90.8%, the same as the combined epidemiological
coverage for the two phases of the campaign. A higher programme coverage of95.6%
was achieved using the school delivery channel than the 87.7% obtained by the
community delivery channel.
Interestingly, in 2004 the programme coverage was higher (93.3%) for the community
based delivery channel than the one achieved by the school delivery channel (89.7%); the
opposite was true in 2005 (85.1% versus 98.2%).
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4.1.2 Costs
The delivery costs, defined as the total campaign costs less the drug costs, of the two rounds of
treatment amounted to US$ 325,936, of which US$ 255,781 (78.5%) were recurrent costs
(defined as delivery costs minus the expenditures made for capital equipment and for training).
The total cost of drugs was US$ 741,348, thus the total costs of the campaign (delivery + drugs)
amounted to US$ 1,067,284 [Table 6].
The cost of each activity at the different administrative levels is also shown in Table 6 and
summarized in Tables 7 and 8. Such tables show that drug costs represented the highest
proportion of expenditure (69.5%), while capital equipment the lowest (1.8%). Briefly, nearly
half (49.5%) of the delivery cost was spent at the CSPS level with the least (7.6%) at the
Regional level.
The analysis of the contributions made by the different financial supporters of the campaign as
indicated in notes to Table 6 shows that SCI-ICL covered 85.7% of the delivery costs (95.7% of
the total costs), communities covered 8.9% of the delivery costs (2.7% of the total costs), and the
national budget (through district budgets) covered 5.4% of the delivery costs (1.6% of the total
costs).
The delivery costs per child treated were US$ 0.098, and US$ 0.084 and US$ 0.107 for the
school-based and the community-based components respectively. The recurrent delivery costs
per child treated were US$ 0.077, and US$ 0.063 for the school-based component and US$ 0.086
for the community-based component. Total costs per child treated (including drugs, and
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assuming US$ 0.075 as cost a tablet of 600mg praziquantel and US$ 0.025 for albendazole
400mg) translates into US$ 0.321, US$ 0.308 for the school-based component and US$ 0.330 for
the community-based component. The details of the costing are given in Table 9.
The results of the sensitivity analysis are summarized in Table 10, and show that while
fluctuations in cost of praziquantel would have a significant impact on the implementation cost
of the campaign, oscillations in remuneration would have a much more limited effect. In
particular, remunerating school teachers with the same amount of financial contribution as
community drug distributors (1,000 FCF A per person for the entire duration of the campaign)
would have a very modest consequence on the overall financial expenditures (+ 10,910 US$).
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Table 7: Expenditures by type of activity (US$)
Activity Budget %
Drugs 741,348 69.5
Remuneration for drug distribution staff 94,280 8.8
Coordination, planning and supervision 91,118 8.5
Training 50,889 4.8
Transportation and logistics 42,775 4
Social mobilization 27,608 2.6
Capital equipment 19,266 1.8
Total 1,067,284 100.0
Table 8: Allocation of resources by administrative level, excluding drugs (US$)
Administrative level Budget 0/0
National 74,243 22.8
Regional 24,899 7.6
District 65,373 20.1
CSPS 161,421 49.5
Total 325,936 100.0
Table 9: Summary of costs per child treated achieved by the intervention (US$)
Per child Per child
Total treated at treated in the Average per
school community child treated
Delivery costs 325,936 0.084 0.107 0.098
Recurrent
delivery costs 255,781 0.063 0.086 0.077
Drug costs 741,348 0.223 0.223 0.223
Total costs 1,067,284 0.308 0.330 0.321
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Table 10: Sensitivity analysis (US$)
Per child treated at Per child treated in Average per childl
Total school the community treatedDelivery Total Delivery Total Delivery Total I
costs costs costs costs costs costs
I
Baseline 1,067,284 0.084 0.308 0.107 0.330 0.098 0.321
I
Scenario 1
(PZQ lowest cost at 961,750 0.084 0.278 0.107 0.297 0.098 0.289 I
0.0729 US$ per tablet
Scenario 2 I
(PZQ highest cost at 1,672,571 0.084 0.483 0.107 0.517 0.098 0.503
0.1544 US$ per tablet)
I
Scenario3
(remuneration ofMoH 1,161,564 0.104 0.335 0.164 0.359 0.126 0.350
staff and cnDs doubles) I
Scenario 4
(school teachers are 1,078,194 0.087 0.309 0.107 0.330 0.101 0.324 I
remunerated as CnDs)
_j
Scenario 5 I
(all lowest costs) 961,750 0.084 0.278 0.107 0.297 0.098 0.289
I
Scenario 6
(all highest costs) 1,777,761 0.107 0.539 0.164 0.596 0.130 0.532 I
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4.2 Impact
A total of 1,727 children were recruited to form the cohort at baseline in 2004 of which 1,131
(65.5%) were successfully followed in 2005 and 596 (34.5%) dropped out. Thus 1131 children
provided information on infection and morbidity indicators specifically haematuria and
nutritional indexes. 763 of them (67.5% or 44.2% of the original cohort) were successfully
followed up in 2006 and therefore provided three sets of longitudinal parasitological data on S.
haematobium infection. 368 (32.5%) who were traced at 1st follow-up missed the 2nd follow-up.
A total of964 (55.8%) children therefore dropped out of the survey.
Drop-out rates of 34.5% at 1st follow-up and 32.5% at 2nd follow-up were better than predicted,
40% per year used in calculating the sample size for the study.
4.2.1 Profile of cohort and drop-out children in the longitudinal survey
The characteristics of the 1131 children recruited at baseline and remained during the I" follow-
up were compared with those of the 596 drop-outs. The mean age of the study participants and
the drop-outs were 9.8 and 11.3 years respectively which was significantly different between
them (P < 0.001). There were also predominantly more males (62.0%) among the dropouts than
among those who remained (55.0%; P < 0.004). Also all the children who dropped out were
wasted (BMIZ < 2 SD) compared to only 32.8% of those followed-up (P < 0.001), and all were
also stunted (HAZ < 2 SD) compared to only 13.3% who remained (P < 0.001). Drop-outs had
slightly higher prevalence of S. haematobium infection (54.1% versus 53.9%), intensity of S.
haematobium infection (94.2 versus 83.6 eggsllO ml of urine), mean Hb concentration (111 gil
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compared to 110 gil) and prevalence of anaemia (66.4% versus 65.8%); these differences were
not significantly different. None of the other parameters differed significantly.
Similar analysis of 763 cohort members followed-up at both 1st and 2nd follow-ups (i.e. 2005 and
2006) and the 964 drop-outs took into account infection indicators only. Compared to those who
were followed-up, drop-outs were characterized by a higher mean age (11.0 years versus 9.6
years; P < 0.01), a higher proportion of boys (59.1 % versus 54.1%; P < 0.05), a lower S.
haematobium prevalence (53.1 % versus 59.9%; P < 0.01). The mean intensity of S.
haematobium infection for the drop-outs was 91.2 eggs/l0 ml compared to 93.3 eggsllO ml for
the cohort group; the difference was not statistically significant (P > 0.05).
4.2.2 Infection indicators: longitudinal survey
The data of the 763 children who remained in the cohort throughout the study were analysed.
The detailed results are given in Tables 11 and 12. The results revealed that the single round of
treatment with praziquantel significantly reduced the prevalence of S. haematobium from 59.6%
at baseline to 6.2% at 1 year post-treatment (-89.6%); an increase to 7.7% (-87.1 %) was
observed at 2 years post-treatment. This observed reduction in prevalence over two years was
significant (P < 0.01).
The overall intensity of S. haematobium infection also reduced significantly from 94.2 eggs/1 Oml
at baseline to 1.0 eggsllOml at 1 year post-treatment (-98.9%) and also increased to 6.8
eggs/1 Oml (-92.8%) at 2 years post-treatment follow-up, The observed trend in reduction was
significant (P < 0.01).
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Significant reductions in both prevalence and intensity of infection were found in all four regions I
I
and in both boys and girls (P < 0.01). The best results in terms of reduction of prevalence of I
infection were recorded in the Nord and Sud Ouest Regions; Nord, Sahel and Sud-Ouest
registered more than 98% in reduction of intensity of infection.
Girls (n=360) registered 93.4% reduction in prevalence of infection which was higher than
82.4% in boys (n=403). Also the reduction in intensity of infection was higher among girls
(98.9%) than in boys (92.1 %).
Before treatment, the proportion of heavy-intensity infections (2: 50 eggs/l0ml) accounted for
over 25% of the schoolchildren examined, while it decreased to just 0.4% at 1 year post-
treatment and remained below 2% at 2 years post-treatment.
Further details are presented in Tables 11 and 12.
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4.2.3 Infection indicators: cross-sectional survey, first-year, 7 year-old
schoolchildren
The baseline characteristics of 7 years old schoolchildren in the original cohort (n= 154) were
compared with the same characteristics of first-year, 7 year-old, schoolchildren newly-recruited
at the 1st and 2nd follow-up (about 20 in each school; their number was 307 in 2004 and 317 in
2005). As previously stated, newly recruited schoolchildren are in principle expected to have
received 1 or 2 rounds of treatment with praziquantel through the community-based delivery
channel of the PNLSc (that targeted children from 5 to 15 years of age) before their admission to
school. Measurement of infection indicators in this group is therefore expected to provide
information on the quality of the community-based interventions.
Similar to the cohort data, 1 year after treatment, overall, both prevalence and intensity of S.
haematobium infection in the 7-year-old children showed a reduction by an average of 82.9%
and 92.3% respectively (P < 0.01). There was a significant uptrend in both overall prevalence
and intensity of infection 2 years post-treatment compared to 1 year post-treatment (P < 0.01),
but the overall level of prevalence and intensity of infection was still far below the original level,
showing a reduction by 65.9% and 78.4% respectively (P < 0.01). More importantly, the
proportion of heavy infections (~ 50 eggsll 0 ml) remained significantly low (2.5%) 2 years after
treatment, compared to 1.6% 1 year after treatment (it was 14.3% before treatment, for an overall
reduction equivalent to 82.1%). The trend in different regions was generally similar with
prevalence and intensity of infection 2 years post-treatment being significantly lower than at
baseline and only moderately higher (in some regions even lower) than 1 year post-treatment. On
the contrary, analysis of gender differences shows that the decrease is overall significant among
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both boys and girls (P < 0.01), but that the increase in infection indicators between first and
second follow-up is much more important among boys than among girls (even though prevalence
remains overall low, and intensity well below the 50 eggs/1 a ml threshold): in fact intensity of
infection among girls further decreased between 2005 and 2006, while prevalence increased only
slightly, and much less than in boys.
Further details are presented in Tables 13 and 14.
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4.2.4 Infection indicators: cross-sectional survey, age- and gender-matched control
schoolchildren
Data refer to measurement of infection indicators at 2nd follow-up only, and specifically to the
comparison between 7-14-year-old schoolchildren in the longitudinal cohort (n=763) and age-
and gender-matched schoolchildren drawn from the same sentinel schools but outside the
longitudinal cohort (school control group, n=761). Such comparison between the followed-up
and the control group is expected to provide information on the quality of the school-based
delivery channel of the PNLSc in children outside the survey cohort, and therefore, also validate
the cohort data by showing that no preferential attention was given to cohort children during
treatment interventions.
Two years after treatment, in this group, overall prevalence and intensity of S. haematobium
infection were significantly lower than those at baseline by 78.9% and 80.9% respectively (P <
0.01). Significant reduction in both prevalence and intensity of infection was shown in all four
regions and in both boys and girls (P < 0.01). As in the cohort data, the proportion of heavy
infections was reduced from 25.2% to just 3.2%.
The comparison between children in the longitudinal cohort recruited at 2nd follow-up and age-
and gender-matched schoolchildren (also recruited at 2nd follow-up) reveals that both prevalence
and intensity of S. haematobium infection were slightly higher in the latter group at 2 years post-
treatment. This difference between the levels of prevalence of infection in the two groups is
significant (P < 0.005), while that between levels of intensity of infection was not (P> 0.05).
Further details are presented in Tables 15 and 16.
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4.2.5 Morbidity indicators: longitudinal survey
Data refer to the children recruited at baseline which were successfully followed up at 1st year
follow-up (2005). They therefore form a sub-group of the original cohort of 1727 and their
number is 1131 (1124 for some of the indicators included in the analysis).
The analysis only takes into account morbidity indicators; however, for reference purposes, data
on infection indicators among these children are also reported here. The number of children on
which it was possible to calculate prevalence and intensity of infection was actually 1124, and
such data are reported in Table 17.
Data on Hb concentration and anaemia were available from 1131 children. A significant increase
in mean Hb concentration and a significant decrease in the prevalence of anaemia were observed.
Haemoglobin concentration increased from 109.7 gil (CI: 108.8-110.5) at baseline to 112.5 gil
(Cf: 111.8-113.2) one year post-treatment, while prevalence of anaemia decreased from 65.75 %
(95 % CI: 62.99-68.52) to 61.59 % (95 % CI: 58.76-64.43) one year post-treatment.
Data on microhaematuria as detected by Hemastix® Bayer were available from 1124 children.
Absence of micro haem aturia increased from 50.44% (CI: 47.52-53.37) at baseline to 89.50% (CI:
87.71-91.29) at l-year follow-up. A shifting towards a reduction in the severity of
microhaematuria was observed for all other categories: (i) Trace: from 12.90% (CI: 10.94-14.86)
to 4.89% (CI: 3.63-6.12); (ii) +: from 6.76% (CI: 5.29-8.23) to 2.31% (CI: 1.43-3.19); (iii) ++,
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from 9.34% (el: 7.64-11.04) to 1.07% (el: 0.47-1.67); and (iv) +++, from 20.55% (el: 18.19-
22.91) to 2.22% rcr. 1.36-3.09).
Data on nutritional status were available from 1131 children. The proportion of thinness or
wasting among sampled children increased from 32.80% (Cl: 30.07-35.54) to 35.10% (Cl:
32.32-37.88), while that of shortness or stunting decreased from 13.26% (Cl: 11.29-15.24) to
11.85% (el: 9.96-13.73).
Further details are presented in Table 17.
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Table 17: Morbidity indicators in children successfully followed up at baseline and first follow-
up
Indicator Baseline, 2004 1st follow-up, 2005
Infectionindicators (n=1124) ,
Prevalence of infection with 53.91 (51.00-56.83) 5.78 (4.42-7.15)
Schistosoma haematobium, %
Intensity of infection with 83.55 (70.14-96.96) 0.94 (0.35-1.53)
Schistosoma haematobium,
eggsllOml
Haematologic indicators(n = 1131) .:... .'
Haemoglobin concentration, 109.7 (10.88 -11.05) 112.5 (11.18 - 11.32)
mean, gil
Anaemia, % 65.75 (62.99 - 68.52) 61.59 (58.76 - 64.43)
Microhaematuria as diagnosed by Hernastix test (n = 1124)
Negative, % 50.44 (47.52 - 53.37) 89.50 (87.71 - 91.29)
Trace, % 12.90 (10.94 - 14.86) 4.89 (3.63 - 6.15)
+,% 6.76 (5.29 - 8.23) 2.31 (1.43- 3.19)
++,% 9.34 (7.64 - 11.04) 1.07 (0.47 - 1.67)
+++,% 20.55 (18.19 - 22.91) 2.22 (1.36 - 3.09)
Nutritional status (n = 1131)
Thinness or wasting, % 32.80 (30.07 - 35.54) 35.10 (32.32 - 37.88)
Shortness or stunting, % 13.26 (1l.29 - 15.24) 11.85 (9.96 - 13.73)
NOTE. Data are means or proportions (95% confidence interval) of children with characteristic, unless
otherwise indicated. Sample sizes are provided in parentheses for each examined outcome in the left-hand
column. Anaemia was defined (according to WHO guidelines) as a haemoglobin concentration <11.5
gldL for children 5-11 years old and <12.0 g/dL for children 12-14 years old. Wasting denotes reduced
body weight for height, defined as a body-mass-index z score less than -2 SD. Stunting denotes reduced
body length in relation to a reference standard, defined as a height-far-age z score less than -2 SD.
Microhaematuria: +, weakly positive; ++, moderately positive; +++, highly positive; epg, eggs per gram
of faeces.
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I
I 4.2.6Baseline indicators of infection with other helminths
I Asdiscussed above, data on prevalence and intensity of infection with S. mansoni, hookworms,
I
I A. lurnbricoides, and T trichiura were also collected at sentinel schools with the aim of assessing
theCo-endemicity of urinary schistosomiasis and other helminth infections. The results at
baselinesampling are presented in Table 18.
Table 18: Indicators of infection with other helminths in the sentinel schools (baseline, 2004)
r--
Prevalence of infection, % Intensity of infection, epg
t-- (95% CI) (95% CI)
Intestinal schistosomiasis 6.16 (4.12-8.19) 8.04 (1 .77-14.3 1)
(S. mansonii (11=33)
~::536)
llookworm infection 6.31 (4.28-8.33) 12.47 (4.92-20.03)
(A. duodenale and N. american us) (11=35)
~::555)
Roundworm infection o (N/A) o (N/A)
(A.lumhricoides) (11=0)
lC.n::553)
Whipworm infection 1.08 (0-2.22) 6.62 (4.22-9.03)
(T. trichiurai (11=6)
lJ!t::553)
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CHAPTER FIVE
DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS
5.1. Introduction
The renewed commitment to fight NTDs experienced in recent years has led a number of African
governments to implement public health interventions aimed at controlling schistosomiasis
(Hotez et al., 2007a). In line with WHO recommendations, these interventions have been based
on preventive chemotherapy, with the aim of reducing morbidity (WHO, 2006). Among such
governments, Burkina Faso has demonstrated full commitment to controlling and eliminating
NTDs, as affirmed by President Blaise Cornpaore in his address to the First Neglected Tropical
Diseases Global Partners Meeting that took place in Geneva on 19-20 April 2007 (Hotez et al.,
2007b). Such support has been instrumental in making Burkina Faso the first country in sub-
Saharan Africa to achieve nationwide coverage with anthelminthic drugs against three major
neglected tropical diseases - namely lymphatic filariasis, schistosomiasis and soil-transmitted
helminthiasis (WHO/AFRO, 2006).
A key component of the implementation of preventive chemotherapy interventions is monitoring
and evaluation which was usually lacking with previous diseases control programmes, and has
been cited by many among the causes of their failures. The aim of this work was therefore to
analyse and discuss the performance and the impact of the nationwide preventive chemotherapy
intervention that was implemented by the MoH of Burkina Faso with the technical and financial
support ofSCI-ICL in 2004 and 2005.
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The implementation of a large-scale preventive chemotherapy intervention was made possible by
the external financial support made available by the B&MGF through the SCI-ICL. It should be
noted, however, that the programme was wholly designed and implemented by local staff relying
on the available local expertise and the existing infrastructure, considering that at time of
implementation Burkina Faso was ranked 175th out of 177 by the Human Devel pment Report
(UNDP, 2005).
In spite of the fact that the programme was essentially disease-specific in scope, it was
remarkable in that it integrated into the implementation structure personnel other than health
staff, namely schoolteachers and community drug distributors, without the creation of a parallel
health system. As a matter of fact, these actors already form part of the "informal" health system
of the country being involved in anum ber of health related issues when need arises, under the
coordination of MoH staff, as it was the case of the campaign described in this thesis. Such facts
were considered an essential contribution towards the building of sustainability in control of
schistosomiasis in the country. Indeed, the full integration of interventions against NTDs,
including schistosomiasis, into the health system of an endemic country is a recognized priority
as well as a much-debated issue (Gyapong et al., 2010), as also is the need for the efficient
coordination among programmes directed against different NTDs (Lammie, Fenwick & Utzinger,
2006; Brady, Hooper & Ottesen, 2006, Hopkins, 2009).
The framework of the programme's implementation offered the unique opportunity to investigate
its performance and impact and to compare these with those conducted differently elsewhere in
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disease endemic countries. The major findings of the study are briefly summarized in Table 19
and thoroughly presented and discussed in the specific sections that follow.
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5.2 Performance
The major strengths inherent in the design of the study on the performance of the schistosomiasis
campaign implemented in Burkina Faso lie in the fact that: (1) it combines costs and coverage,
thus allowing a full understanding and appreciation of the intervention implemented by the MoH
(for example: the denominator by which total costs are divided in order to obtain costs per person
treated is not an estimate but a "true" figure); (2) it describes a programmatic intervention in its
full national scale, with no geographical extrapolations of data; (3) it considers all the delivery
channels implemented by such intervention, namely both the school-based and the community-
based ones. In brief, the added value of this design is that it is more complete than most of the
studies carried out so far in this regard.
5.2.1 Coverage
The PNLSc was officially launched on 6 May 2004 and within 6 months from this date slightly
less than one third of the country's school-age population had been treated, and 18 months later
almost the entire school-age population of Burkina Faso had been reached. With this campaign,
the country fully attained and indeed exceeded the 75% coverage goal set by WHA Resolution
WHA54.19 (WHO, 2002).
Coverage is increasingly recognized as the key indicator for monitoring and evaluating
preventive chemotherapy interventions (WHO, 201Oa). First it is for a programmatic reason, in
that, monitoring coverage is the simplest tool to monitor the progress made by health systems
towards provision of health services against a given disease. In the case of schistosomiasis,
coverage data are also essential in order to track the attainment of the coverage goals set by
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WHA Resolution WHA54.19. The second reason is that coverage data are very useful proxy
indicators for estimating the impact of a given disease control intervention. In the case of
schistosomiasis, substantial data exist which show the correlation between administration of
praziquantel and reduction of morbidity, therefore it can be inferred that if individuals are treated,
they do experience a reduction in morbidity. In situations where lack of resources prevents the
conduct of monitoring and evaluation on impact, coverage may serve as a proxy indicator for
impact.
In order to overcome the difficulties associated with the high proportion of non-enrolled children
especially in rural areas, the MoH of Burkina Faso adopted two combined drug delivery channels
and in order to avoid any overlapping and duplication of activities, the two channels were kept
separate. School teachers were responsible for treating enrolled children on school premises and
community drug distributors responsible for reaching all those out of school. The results
obtained using this dual approach on a national scale were very good and encouraging [Tables 4
and 5]: reported epidemiological coverage, as well as the programme coverage rates were very
high for both the school (95.6%) and the community component (87.7%). The coverage of the
latter although lower than that achieved in schools, was high compared with coverage reported
by other countries implementing large-scale control of schistosomiasis (WHO, 201Ob:WHO,
. 201 Oc). As reflected in the estimated primary net enrolment rate (higher for males than for
females), 54;9% treated children in schools were males and 45.1% were females, which is
reflected by the fact that more females than males were treated in the community (50.6% and
49.4%, respectively).
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The lowest community coverage rates were recorded in the major cities of Ouagadougou and
Bobo-Dioulasso (pop. 1.2 million and 0.6 million inhabitants respectively), being 61.1% and
77.4% respectively. The consideration that both cities were targeted in 2005 could explain the
fact that programme coverage rates obtained in the 2nd phase of the campaign (2005) were lower
than in the 1st phase (2004). It was widely recognized by field-based officers that drug
distribution activities were more difficult to implement in large cities due to loose social
structures that pertains there and the consequent difficulties in mobilizing individuals and
reaching non-enrolled children (Seydou Toure, personal communication).
5.2.2 Costs
Drugs formed the largest component of the overall expenditures (69.5%), far exceeding delivery
costs [tables 6 and 7]. This was largely attributable to praziquantel, one of the most expensive
anthelminthic drugs currently available, which represented more than 88% of the drug costs (the
unit cost of this medicine (600 mg tablet) was US$ 0.075 and on average children required 2.5
tablets, while the unit cost of albendazole (400mg) was US$ 0.025 cents and each child required
only one tablet). In addition, the sensitivity analysis [Table 10] shows that oscillations in the cost
of praziquantel registered in the current international drug market have indeed the potential to
increase significantly the overall costs of interventions such as those implemented in Burkina
Faso (+ US$ 605,287 or +56.7%).
The distribution of costs along administrative lines reflects the extent of decentralization in
decision-making and delegation of responsibilities to peripheral health authorities [Table 8]. The
national level accounted for only 22.8% of the recurrent expenditure compared to the 69.6% by
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the two lowest implementation levels (i.e. districts and dispensaries). Delegating responsibilities
to peripheral units of the MoH proved a successful decision and was instrumental in empowering
field staff thus achieving high coverage rates.
The delivery cost per treated child with the school-based distribution was US$0.084 and for the
community-based distribution was US$0.107; thus, an additional US$ 0.023 was registered when
treatment was conducted in the community [Table 9]. In contrast with what shown in the case of
drug costs, the sensitivity analysis indicates that oscillations in the factors contributing to
delivery costs - such as the doubling of the remuneration for MoH staff and CDDs and the
introduction of remuneration for schoolteachers - would only have a limited impact on the
overall costs (+ US$ 94,280 or +8.8%, and + US$ 10,910 or +1%, respectively) [Table 10]. This
is explained by the limited proportion of such costs represented by delivery costs (less than one
third of the expenditures incurred for the implementation of the campaign).
Overall, the community-based delivery channel did not add significantly to the programme's
expenditure, as such increase amounted at US$ 46,527 which was basically in the form of
remuneration and fuel for the distributors. This amount formed 14.3% of delivery costs and 4.4%
of the total costs of the campaign [see Table 6; data not shown].
The average delivery cost per treated child, irrespective of the delivery channel used, was
calculated to be US$ 0.098 [Table 9]. This figure compares favourably with US$ 0.096 reported
by Sinuon et at. (2005) for the first round of a national school-based deworming campaign with
mebendazole in Cambodia. If only the school-based component is considered, the delivery cost
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ofUS$ 0.084 for each treated child was lower than the US$ 0.096 of Cambodia, notwithstanding
the fact that in Cambodia the distributed drug was albendazole, which apart from being cheaper
than praziquantel, also requires minimum expenditures with regards to capital equipment and
training i.e. no need for dose-poles and training necessary for praziquantel administration.
The recurrent delivery costs of programmes give an indication of the implementation cost of
subsequent treatment campaigns, based on the assumption that capital investments would be
minimal and less training sessions would be required in the subsequent years. Phommasack et al.
(2008) have reported US$ 0.060 as the unit recurrent delivery cost for a school deworming
intervention in the Lao People's Democratic Republic compared to US$ 0.077 registered in
Burkina Faso. However exact comparison with the Lao experience might not be possible because
Phommasack and colleagues included in their analysis, areas that had been treated more than
once, and also only targeted schools; in fact, if we only take into account the school delivery
channel in Burkina Faso, the gap between this country and Laos is sharply reduced (US$ 0.063
versus US$ 0.060).
In the more appropriate context and social structures of Africa, delivery costs per treated child in
Burkina Faso were overall higher than those reported by Kabatereine et al. (2005) for school-
based distribution ofalbendazole in Uganda (US$ 0.040 to US$ 0.081 in different districts).
Again the two scenarios may not be may not be wholly comparable in that Kabatereine and
colleagues considered district level costs only thus excluding from their analysis expenses made
at central level. Also the authors included in their analysis areas where treatment activities had
already been conducted the previous year: in fact, the comparison between costs reported by
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Kabatereine and the recurrent delivery costs calculated in Burkina Faso shows that figures are
largely overlapping.
Comparison with the Ugandan study is made even more difficult by the assumption made by
Kabatereine et al. (2005) that the delivery costs for each drug (praziquantel and albendazole)
were the same but only the data on the albendazole were reported. The analysis presented in this
thesis avoided splitting 50:50 the delivery costs ofthe school-based component because
operational costs (e.g. training and social mobilization) are largely independent of the number of
distributed drugs and are therefore not subject to major changes. In other words, certain
operational support costs remain the same even if a second drug is added to the distribution of
another, provided the distribution channels for the two drugs are the same, as they are in the case
of Burkina Faso.
It is known that the delivery cost of re-treating children in areas where similar interventions have
been previously implemented is reduced because activities such as training need not be repeated
on the same scale, and capital investments (dose poles, buckets, cups) also need not be re-
purchased unless damaged. This observation has been reported in Cambodia (Sinuon et al., 2005)
and also in Vietnam which registered an impressive significant reduction in expenditures per
treated child when programmes expanded its coverage in subsequent years (Montresor et al.,
2007). It should therefore be expected that the delivery costs will decrease in subsequent
exercises in Burkina Faso and reach the levels of the recurrent delivery costs presented in this
thesis.
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Delivery costs per treated child reported here were also lower than US$ 0.67 and US$0.21
reported from Ghana and Tanzania respectively for school-based delivery ofpraziquantel alone.
However, the two countries conducted prior screening for visible haematuria at school level
which contributed to the costs (Partnership for Child Development, 1999) and therefore render
them inappropriate for comparison. Selective treatment (i.e. diagnose-and-treat approach)
adopted by Egypt for integrated control of schistosomiasis, soil-transmitted helminthiasis and
fascioliasis in Behera governorate (Curtale et al., 2003) also registered higher (US$0.15 per
treated child) than that reported here.
The total costs (including drug cost) per treated child presented in this thesis were in the same
range as those reported by Kabatereine et al. (2006b) in a different study conducted in three
Ugandan sub-counties as pilot phase of a combined school and community-based campaign
distributing praziquantel and albendazole, which was US$ 0.34. This value is similar to that
reported by Brooker et al. (2007) in a retrospective analysis of the costs of the implementation of
the only school-based component of the same control intervention in 6 districts of Uganda which
was US$ 0.39. Figures from both countries are only slightly above the lowest figures (US$ 0.25-
0.30) suggested by WHO for routine, school-based delivery of both anthelminthic drugs (WHO,
2002). On the contrary, total financial costs per child treated in Burkina Faso were lower than
those estimated in Ghana (US$ 1.22) and Tanzania (US$0.79) for school-based delivery of
praziquantel, even though this older data are likely to reflect the higher cost of praziquantel in
the 1990s compared to the years 2000s (Partnership for Child Development, 1998; 1999). These
considerations therefore limit the appropriateness of any historical comparison between recent
and older treatment exercises.
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The analysis of the sources of the financial contributions to the campaign presented in this thesis
shows that 1.6% of the total budget or 5.4% of the delivery costs were incurred by the national
budget (US$ 17,448), while community-generated financial contributions (US$ 29,079) formed
2.7% of the total budget or 8.9% of the delivery costs [see Table 6; data not shown]. These might
appear as relatively low inputs and be wrongly interpreted as suggesting that the contribution to
the campaign given by national entities was modest. On the contrary, such moderate financial
contributions were counterbalanced by the significant support from governmental staff working
in the health and education sectors and from community members in terms of worktime
dedicated to the campaign. In fact, remuneration, when applied, only compensated for a fraction
of the worktime dedicated to the campaign by such individuals, which was mostly covered by
salaries. However, given that the present analysis is limited to financial costs and does not take
into account economic costs such as salaries, and given that economic costs are mainly covered
by national entities (government and communities), the national contribution appears downsized.
In addition, non-quantifiable inputs in terms of commitment, enthusiasm and dedication are also
not taken into account, in spite of their being key factors in sustainability. Overall, the experience
of Burkina Faso during 2004-2005, shows that if support is provided to cover the immediate
expenditures that are inherent in public health interventions, a resource-poor country such as
Burkina Faso is able to implement helminth control on a nationwide scale, thus attaining the goal
of Resolution WHA54.19 (WHO, 2002).
In fact, Burkina Faso has had long experience with large-scale public health interventions, such
as vaccination outreach and lymphatic filariasis elimination campaigns. This must have aided in
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the decision to embark on large-scale control of schistosomiasis and soil-transmitted
helminthiasis and also helped achieve the set objectives. The option for a campaign approach as
the most appropriate way to sensitize populations to a "neglected disease" control - as opposed to
control activities in countries that initially commence on a small scale and expand over time to
achieve a wider geographical coverage - has been justified by the very good results that were
obtained. The high coverage attained throughout the country shows that the strategy of "actively"
delivering drugs to those in need justifies the adoption of this approach.
However, the attainment of a high coverage and consequently the protection of Burkina Faso' s
school-age population from schistosomiasis-associated morbidity is not the only benefit
generated. The added benefits include the building of local competency and capacity for control
of helminth infections through training programmes. They also include the creation of awareness
and increase in the target disease's public health profile. In most cases successful public health
programmes also indirectly influence the nation's agenda by raising diseases to levels to be
considered public health priorities.
comparison of data presented in this thesis and those generated elsewhere indicate that a number
of countries including Burkina Faso have raised the campaign approach to schistosomiasis
control to high levels of performance. In spite of this, such an approach would still be
unaffordable by most developing countries and would require financial support from external
donors, especially for procuring drugs, which constitute the most conspicuous budgetary line. In
this regard, a step towards sustainability would be the establishment of a mechanism whereby
praziquantel is regularly donated by manufacturers to endemic countries (as is the case for
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albendazole and ivermectin for lymphatic filariasis). This is in fact already happening thanks to
the establishment of the Merck Praziquantel Donation Program (MPDP), which is a partnership
between the Merck Group and WHO. Merck Group has agreed to provide 200 million tablets of I
praziquantel to endemic countries from 2007 to 2017. The MPDP has allowed the most needy
African countries to start or revive schistosomiasis control activities because of 20 million tablets I
promised each year. This is however not sufficient to cover all the needs of ~ub-Saharan Africa,
let alone those of all endemic countries. For example Burkina Faso has been excluded from the
recipient countries as such country is already supported by a number of organizations and
therefore could not be considered among those most in need.
The increasing tendency of endemic countries to integrate large-scale national programmes
would also help achieve sustainability of helminth infections control from the drug perspective.
For example, in Burkina Faso, as lymphatic filariasis, schistosomiasis and soil-transmitted
helminthiasis are co-endemic therefore the PNLSc has stopped administration of albendazole
because the Global Programme for the Elimination of Lymphatic Filariasis achieved a yearly
nation-wide coverage with albendazole and ivermectin in early 2006 and is still implementing
mass drug administration (MDA) interventions to eliminate the disease (WHO, 201Ob): the
rationale is that albendazole treatment against lymphatic filariasis also controls morbidity due to
soil-transmitted helminth infections.
Another contribution to sustainability, backed by the data presented in this thesis, would be to
optimize drug use through the appropriate determination of the interval ofre-treatment. Finally, a
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progressive integration of regular anthelminthic treatment into the routine health care services in
the long run would also contribute to sustainable programmes.
5.3 Impact
The present study assessed the impact of large-scale distribution of praziquantel on selected
indicators of infection and morbidity associated with urinary schistosomiasis (S. haematobium
infection), one and two years after a single treatment, among school-age children. It acquired a
large detailed dataset drawn from 16 primary schools randomly selected across the various
ecological areas of Burkina Faso. The study was designed to generate reliable evidence
compared to previous studies conducted elsewhere that have usually investigated few parameters
of impact and have also considered control programmes adopting a shorter interval of re-
treatment.
The 16 schools could be considered as a good representative sampling of schools in the country:
locations in diverse ecological areas, different transmission levels, school children from different
backgrounds, including children from a medersa (Islamic school), and from all classes and
different ages. It is therefore reasonable to believe that the selected children - in reason of their
number, origin and background - formed a true representative of the school population of
Burkina Faso.
A point of strength of the design of the study presented in this thesis is the fact that it focuses on
a combination of infection and morbidity indicators, while previous studies have rather focused
on singular impact indicators such as Hb concentration and anaemia only (Guyatt et al., 2001;
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Koukounari et al., 2006a; Tohon et al., 2008), parasitological indicators only (Nagi, 2005;
Saathoff et al., 2004), or morbidity indicators only (Magnussen et al., 2001). What was unique
was that the MoH conceived all monitoring activities as "embedded" within the large-scale
intervention.
Another characteristic of the data presented in this thesis is that it provides evidence on the
impact of treatment on urinary schistosomiasis without major confounding factors. This is so
because the data were generated in areas where the prevalence of intestinal schistosomiasis,
hookworm and other soil-transmitted helminth infections (all infections treated by praziquantel
or albendazole) were low: the measured health outcome can therefore be attributed to the effect
of praziquantel on schistosomiasis. This conclusion is further supported by the consideration that
although the survey that was carried out was not controlled and therefore other factors may have
played a role in influencing the observed health outcomes, however there were no concurrent
significant large-scale public health interventions in the study areas other than the routine
primary health care activities that are carried out there. A possible exception is possibly
represented by the activities of the lymphatic filariasis elimination programme (LFEP),
implementing mass drug administration (MDA) with albendazole and ivermectin (Molyneux et
al., 2003) in Sud-Ouest during the period of the study (WHO, 2010b). However these drugs are
effective against soil-transmitted helminthiasis, but not on schistosomiasis (neither ivermectin
nor albendazole are active against Schistosoma spp).
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The findings of the study just as with any other research studies might however be undermined
by a number of weaknesses inherent in the study design. The following points therefore describe
such risks and indicate the steps that were taken to mitigate them.
• Sentinel schools were drawn from four regions of the country out of the 13 targeted by
the PNLSc.
o Risk: not all the regions of the country are represented.
o Mitigation: the four regions stretch across the country, from north to south, from
west to east; sentinel sites have been selected from all the different ecological
areas of Burkina Faso (Sahelian, Sahelo-Sudanese and Sudanese), which were
representative of all the epidemiological scenarios and transmission pictures of
schistosomiasis
• Sentinel sites were exclusively located in regions treated in 2004.
o Risk: only data of the 2004 phase of the campaign were collected and therefore
extrapolation to cover the 2005 phase might not be true with the consequence that
the full impact of the whole programme implemented by the PNLSc cannot be
assessed.
o Mitigation: the 2005 phase of the treatment campaign was implemented exactly in
the same manner as that of2004. The geographical characteristics of the areas and
the social characteristics of the populations targeted in 2004 do not differ from
those of the treated individuals living in areas in 2005. Moreover the areas
targeted in 2004 were the most endemic areas in Burkina Faso: if levels of
infection and morbidity indicators were therefore low as observed two years after
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treatment there then, it is reasonable to postulate that they would be even more
satisfactory in less-endemic areas that were covered during phase two.
• Only children attending school were included in the longitudinal survey
o Risk: the longitudinal survey was only geared to provide information on the
school-based drug delivery channel and therefore no inference could be made
from the impact data to cover non-enrolled school-age children.
o Mitigation: 7-year-old-first-year schoolchildren were recruited at follow-up 1 and
follow-up 2 with the aim of providing information on the performance of the
community-based drug delivery channel.
• No control group participated in the study
o Risk: the absolute impact of the disease control activities implemented cannot be
assessed.
o Justification: the establishment of a true control group and comparison with
untreated individuals is not possible because it is unethical to prevent children
living in schistosomiasis-endemic areas from being appropriately and timely
treated.
o Mitigation: age- and gender-matched schoolchildren were recruited at 2nd follow-
up with the aim of providing school control data and allow comparison with
children in the original cohort. Even though this cannot be considered as a true
control, it nevertheless provides information on potential risk for "preferential
treatment" given to children enrolled in the longitudinal cohort.
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5.3.1 Infection indicators
The findings of the present study with regard to infection indicators [Tables 11-16] confirmed
those of previous epidemiological investigations conducted in Burkina Faso (CNRS & WHO,
1987; Poda & Traore, 2000; Poda, Traore & Sondo, 2004; MoH, unpublished data), namely: (1)
that in absence of control measures S. haematobium is intensely transmitted in all ecological
zones of the country while S. mansoni is restricted to the southernmost Sudanese ecological zone;
(2) that in absence of control measures, transmission of schistosomiasis haematobia is more
intense in northern Burkina Faso, and consequently the prevalence of infection decreases
gradually southward to moderate levels in the Sud Ouest Region; (3) that in absence of control
measures the burden of schistosomiasis haematobia among school-age children is significant; (4)
that soil-transmitted helminth infections (Ascaris lumbricoides, Trichuris trichiura and
hookworms), occur in foci widely distributed throughout the country, with an almost regular
overlap with schistosomiasis-endemic areas. Prevalence and intensity of infection with soil-
transmitted helminths are however generally low.
In line with other investigations conducted in a number of endemic countries (Doehring et al.,
1986; King et al., 1988; Devidas et al., 1989; Hatz et al., 1990; King et al., 1990; Laurent et al.,
1990; Kardorff et al., 1990; Magnussen et al., 1997; Medhat et al., 1997; Delegue et al., 1998;
Hatz et al., 1998; Wagatsuma et al., 1999; Reimert et al., 2000; Campagne et al., 2001;
Magnussen et al., 2001; Garba et al., 2004), this study shows that a single administration of
praziquantel is effective in significantly reducing prevalence and intensity of S. haematobium
infection one year after treatment; this is confirmed throughout all the sentinel sites. In addition,
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the present study shows that such reduction was still significant 24 months post treatment
[Tables 11-16].
The significant reductions in prevalence and intensity of infection, as well as in the proportion of
heavy-intensity infections were confirmed by the results of all the monitoring and evaluation
components: the longitudinal cohort study, the cross-sectional survey of the newly-enrolled
children and also the cross-sectional school control survey conducted in the second year post
treatment [Tables 11-16]. Such decreases were substantial in all cases and any observed
differences among them were insignificant in terms of public health. For example at 2nd follow-
up prevalence of infection in the different study groups was below i.e. 7.7%, or only slightly
higher (i.e. 14.2% and 12.6%) than 10%, the level that distinguishes moderate-risk communities
from low-risk communities (WHO, 2006). The intensity of infection was well below the heavy-
intensity threshold of 50 eggsll Oml, (WHO, 2002) in all cases, at 6.8 eggsll Oml, 13.7 eggsll Oml
and 18 eggs/l0ml respectively. The proportion of individuals with heavy-intensity infections was
very low for each of the three study groups at 2%,2.5% and 3.2% respectively.
Significant decreases in prevalence and intensity of infection were observed in all the Regions
under study. The Region where the overall lowest reduction in prevalence of infection occurred
is the Sahel. This can be explained by the higher transmission rates typical of this arid area (as
reflected by higher levels of prevalence and intensity of infection registered at baseline), a fact
that entails a (more) rapid re-infection of the children and therefore more severe infection
indicators at follow-up. This emerges clearly from the cross-sectional study components; it is
also confirmed by the comparison between 2004 and 2005 data from the longitudinal component,
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while comparison between 2005 and 2006 data indicates that re-infection between first and
second follow-up was minimal and in fact both prevalence and intensity of infection decreased
between such dates. This could suggest either a significant suppression of transmission of
schistosomiasis haematobia as an effect of the treatment intervention or the introduction of a bias
such as the occurrence of preferential attention to these children in the treatment and/or in the
post-treatment phase, or biases of other origin (see section 5.3.3). Such reductions were also
clear in both gender groups, however the most significant impact of treatment, at both follow-ups,
was registered among girls. This fact might be a reflection of the lower likelihood of engaging in
behaviours known to be correlated with Schistosoma spp. infection, especially that of bathing in
bodies of water, and the consequent lower re-infection rates in the interval between treatments.
As mentioned above, the typical gender pattern of schistosomiasis shows higher prevalence and
intensity of infection among males than females (Ansell et al., 2001; Ndyomugyenyi & Minjas,
2001; Bowie et al., 2004; Clements et al., 2008), a fact usually attributed to different frequencies
of water contact.
5.3.2 Morbidity indicators
One year after treatment, morbidity indicators equally showed changes, reflecting the reduction
of levels of infections in the study population. The pattern of microhaematuria, in particular,
showed a marked shift towards the lower end of the spectrum of severity, a finding that is
expected for an indicator considered a specific marker of infection with S. haematobium in areas
of high intensity transmission (Murare & Taylor, 1987; Nwaorgu & Anigbo, 1992; Aryeetey et
al., 2000). The findings of the present study [Table 17] are in line with previous investigations
on the impact of treatment with praziquantel on microhaematuria in S. haematobium-endemic
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areas (Doehring et al., 1986; Devidas et al., 1989; Laurent et al., 1990; Hatz et al., 1990; King et
al., 1990; Beasley et al., 1999; Rollinson et al., 2005).
The less specific indicators such as mean Hb concentration showed a slight but statistically
significant increase after treatment, but although a reduction in the proportion of anaemic
children was observed, it was not significant [Table 17]. The impact ofthe treatment on Hb
concentration and anaemia therefore was less striking than that achieved by similar intervention
programmes in Tanzania and Niger (Guyatt et al., 2001; Magnussen et al., 2001; Tohon et al.,
2008), and by an intervention against intestinal schistosomiasis in Uganda (Koukounari et al.,
2006a). The multi-factorial nature of both morbidity indicators should however be emphasized, a
fact that suggests that schistosomiasis is only one among many factors that could have influenced
the level of Hb concentration and the anaemic status of children living in endemic areas of
Burkina Faso. Guyatt et al. (2001), for example, estimated that in selected schools in the Tanga
region of Tanzania where the average prevalence of infection with S. haematobium was
equivalent to 59%, schistosomiasis was responsible for 15% of anaemia cases. Malnutrition or
malaria are likely to be major factors contributing to reduced Hb concentration and anaemia,
however their specific contribution can not be inferred as this was not investigated by the present
study.
Similarly, highly-aspecific indicators such as the proportion of children suffering from wasting
or stunting only showed changes that were not found to be statistically significant [Table 17].
However, data indicated some reduction in the proportion of stunted children, suggesting the
possibility that urinary schistosomiasis could play some role in the establishment of chronic
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undernutrition. This finding is in line with recent reassessments of the pathogenesis and the
burden of disease associated with schistosomiasis which suggested that impaired growth of
children is indeed included among the recognized "subtle" and frequently overlooked health
outcomes of schistosomiasis (King, Dickman & Tisch, 2005). In addition, even before this
reassessment, reports and publications had already emphasized the relationship between
helminth infections and malnutrition (World Bank, 1993; Stoltzfus et al., 1997), and had
highlighted that urinary schistosomiasis is associated with inhibited child growth (Parraga et al.,
1996) and that growth rates actually improved following treatment with praziquantel (Latham et
al., 1990; Stephenson, 1993). The evidence provided by the study adds to this body of
information that a single administration of praziquantel seems to produce some effect on this
multi-factorial indicator 12 months after treatment. The results obtained also show a non-
significant increase in the proportion of wasted children one year after treatment, suggesting a
lack of association between infection with S. haematobium and acute malnutrition; a fact that
finds its plausibility in the overall chronic nature of schistosomiasis.
No morbidity data were collected at the 2nd follow-up, however, two years after treatment, the
overall prevalence of S. haematobium infection among school-age children remained
significantly lower than at baseline and, more importantly, intensity of infection remained at a
very low level. The mean intensity of infection of the children in the original cohort followed up
in 2006 was 6.8 eggs/10ml which was well below the threshold of 50 eggs/10ml for heavy
intensity of infection. It is at this threshold and above that morbidity associated with urinary
schistosomiasis is likely to appear (WHO, 2002). The proportion of heavy-intensity infections
was consequently greatly reduced, and in fact only 2.0% of the children had an intensity of
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infection higher than 50 eggsll Oml in 2006. This finding is quite significant because of the direct
relationship between intensity of infection and morbidity; it is therefore reasonable to conclude
that, even in absence of morbidity data at the year two follow-up, morbidity due to urinary
schistosomiasis was under control in 98% of the school-age children in the sentinel schools.
5.3.3 Comparison between the longitudinal and the cross-sectional surveys
The prevalence and intensity of infection in the 763 individuals of the original cohort and the 761
age- and gender-matched schoolchildren recruited at 2nd follow-up were compared. The aim was
to determine the value of long-term as opposed to cross-sectional surveys for monitoring and
evaluating disease control interventions. The baseline prevalence and intensity of infection rates
were assumed to be the same for the two groups which were 59.6% and 94.2 eggsllOml
respectively. At 2-year follow up, the prevalence and mean intensity of infection of the cohort
were 7.7% and 6.8 eggs/l0ml, and 12.6% and 18 eggsllOml for the matched control group. The
difference in prevalence of infection between the two groups was statistically significant (P <
0.005), while the observed difference in intensity of infection and in the proportion of high-
intensity infections was not (P >0.05).
The statistically significant difference in levels of prevalence of infection recorded by the two
surveys most likely reflects the influence of the two monitoring & evaluation methods. The
identification of each child, at each time of the longitudinal survey, is likely to have impacted on
the risky behaviour of the cohort members. In addition, the fact that cohort members were
identifiable, might have produced a preferential attention at treatment time or during the post-
treatment phase. Moreover, since for longitudinal surveys no new children are introduced, the
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chance of untreated children joining the cohort group is eliminated. Finally, children dropping
out of the cohort introduce an additional further bias that the most affected children are those
most likely to abandon school because of their less affluent social background. The converse of
these reasons therefore holds for the poorer impact indicators observed for the individuals
involved in the cross sectional study. As a matter of fact, the introduction of a bias into a
longitudinal cohort can never be excluded, as the close supervision of the cohort members -
finalized to ascertain that no bias occurs - is responsible for trigging a vicious circle whereby the
supervision itself determines a bias.
In conclusion longitudinal studies provide a better representation of the maximal impact
produced by an ideal disease control intervention, while cross sectional surveys depict a real case
scenario and are more geared to provide information on the expected average impact.
However, the fact that the difference in mean intensities of infection between the two groups
was not statistically significant as well as the consideration that intensity of infection can be
considered as a proxy indicator for morbidity, allows concluding that in terms of control of
morbidity, that is the objective of the treatment intervention (WHO, 2002 and 2006), the two
survey methods provided similar results. This conclusion is further supported by the
consideration that the difference between the proportion of heavy-intensity infections in the two
groupS was 2.0% and 3.2% which was also statistically not significant (P >0.05).
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5.3.4 Comparison with disease control interventions implemented elsewhere
Previous control interventions against S. haematobium in Uganda, Kenya and Tanzania have
mostly employed yearly treatment with praziquantel (Magnussen, 2003; Kabatereine et al.,
2006b and 2007; Satayathum et al., 2006; Zhang et al., 2007). Consequently, their impacts could
only be assessed 12 months after treatment or before.
Conversely, in west Africa, attempts have been made to assess the long-term impact of a single
praziquantel treatment. It has been reported from Niger that three years after a single treatment
with praziquante1, prevalence, intensity and morbidity due to S. haematobium infection remained
significantly lower than at baseline (Campagne et al., 2001; Garba et al., 2004). In another study
in Ghana (Nsowah-Nuamah et al., 2004), one single administration ofpraziquantel was able to
significantly reduce intensity of S. haematobium infection (in the range of 80-99%) 12 months
after treatment, which still remained very low in two of three study areas 24 months after
treatment. Furthermore previous studies conducted in Burkina Faso in 1984 had shown that
prevalence and intensity of infection with S. haematobium remained at low levels three years
after treatment with metrifonate in a dry savannah village with sedentary population and
transmission limited to small ponds. The long-lasting impact of treatment on infection indicators
reported by this study was particularly evident in adults, but not particularly so in children (Sellin
et al., 1984). The results reported by this study are in line with those of these studies, suggesting
that a more spaced interval between treatment rounds should be sufficient to produce and
maintain the desired impact on morbidity even in highly endemic areas and for longer than
expected.
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Three factors are likely to have contributed to the impact observed in the present study.
The first is the high epidemiological and geographical treatment coverage of over 90% and 100%
achieved in the relatively short time of 12 months. The second is that 2004 was a dry year,
characterized by a short rainy season. In addition, treatment was done in the dry season which is
a period of low transmission (because of the lower number of water bodies left in reason of the
dryness). The treatment therefore might have resulted in a "neutralization" of a large proportion
ofthe individuals likely to be responsible for environmental contamination with S. haematobium.
eggs. As such, the documented decrease in infection and morbidity indicators might not have
been the direct result of treatment only, but also the effect of a decrease in transmission and re-
infection episodes, indirectly determined by treatment itself. The third factor is that that the
treatment campaign was coupled with information-education-communication (IliC) activities
that may have produced an increased health awareness resulting in some change in behaviours
and practices associated with the risk of infection during period post treatment.
5.3.5 Drop-outs
One of the lessons learnt from the programme's implementation is the difficulty related to the
conduct oflongitudinal follow-ups in rural west African settings. The drop-out rates among the
cohort children could be considered high, particularly in the Sud-Ouest region where only very
few original children in the cohort group were traced and re-examined at both follow-ups. Apart
from the fact that a proportion of the original cohort (older age groups) had naturally progressed
to secondary schools over the study period, one of the main reasons for the loss of cohort
children can be identified, at least partially, in the customary practice of family migration for
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agriculture, which is very common in the country and particularly in the Sud-Ouest (Seydou
Tourc, personal communication).
Nevertheless, the significant difference in nutritional status between children traced at the first
follow-up and drop-outs suggests that malnourished children may come from marginalized social
and economic backgrounds which in turn increase their likelihood of dropping out of schools. As
a consequence, in terms of control interventions, special efforts should be dedicated to ensure
that non-enrolled school-age children are targeted by large-scale drug distribution interventions.
Drop outs have been shown to be those who are most in need of treatment (Husein et al., 1996),
as well as those in which the biggest gains in terms of health can be expected after administration
of praziquantel (Coutinho et al., 2006).
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5.4 Conclusions and Recommendations
The results obtained by this study show that a combined school- and community-based drug
distribution strategy is effective in attaining and exceeding the minimum coverage rate set by
resolution WHA54.19 (75%) among school-age children (both enrolled and non-enrolled) in a
country where school enrolment is low and where the number and/or size of the primary schools
are not sufficiently large to justify their use as the exclusive drug distribution channel for large-
scale administration of drugs to control urinary schistosomiasis.
These findings also indicate that implementing a community component does not significantly
increase the budget of a deworming campaign, and that overall delivery costs per child treated of
the combined school- and community-based strategy implemented in Burkina Faso are
comparable to those of school-based only treatment exercises implemented in African countries
and elsewhere in other parts of the world. Furthermore, the analysis of the recurrent costs
suggests that delivery costs are expected to decrease further with each subsequent round of
treatment.
The results also demonstrate that schools are the most efficient way of reaching children as
shown by the lower delivery costs per child treated at school and the higher coverage rates
attained through the school-based channel. The recommendation then is that in endemic areas
where school enrolment is high, schools should be considered the main or exclusive delivery
channel. In this regard, the rising rate of school attendance observed in many African countries
(Yamcy, 2010) is expected to provide a significant opportunity to reach children burdened by the
disease. On the contrary, where school enrolment or where the number or size of the schools are
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both low both distribution channels should be used in parallel in order to reach the maximum
number of children at the lowest cost. On the contrary, the implementation of community-based
drug distribution strategy alone should be discouraged.
The data also show that a single administration of praziquantel achieved a dramatic reduction in
both prevalence and intensity of S. haematobium infection which remained very low two years
post-treatment. The substantial impact on infection and morbidity indicates that a large-scale·
control programme is as effective as the small-scale or pilot projects from which most of the
literature on the subject is derived. It also indirectly confirms the high coverage rates that were
achieved and that have been discussed in the section dedicated to performance.
In terms of policy, the findings indicate that an interval of two years between two subsequent
treatments with praziquantel, i.e. more spaced than currently recommended by WHO, should
maintain low levels of prevalence and intensity of infection, of the proportion of heavy-intensity
infections and of associated morbidity in highly endemic settings. More precisely, a calendar of
retreatment with single administration of praziquantel every two years would be sufficient to
control morbidity associated with urinary schistosomiasis.
The current availability of praziquantel on the international market, either donated or to be
purchased, is insufficient to meet all schistosomiasis control needs and despite the significant
price reductions in the recent years, it still remains one of the most expensive anthelminthic
drugs; this study in fact shows that consequently drug costs form the most significant proportion
of the total costs of schistosomiasis control programmes and can be increased by praziquantel
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cost fluctuations in the current drug market. All these considerations call for an optimization of
the timing for re-treatment and for the definition of the most appropriate interval of re-treatment,
as pointed out by Gurarie & King (2005). The recognition that the impact of large-scale
distribution of praziquantel is satisfactory two years after treatment, should therefore contribute
significantly to reducing implementation costs and ultimately, to increase sustainability of
intervention programmes.
The practical advice to programme implementers would be to invest the savings from the
reduction in treatment frequency into strengthening monitoring and evaluation activities, which
are usually not accorded sufficient importance in schistosomiasis control programmes. This
would allow for fine-tuning of the intervention strategies as programme implementation
progresses. The initial decision taken by the MoH of Burkina Faso and SCI-ICL to adopt a two-
yearly retreatment was mainly based on logistic rather than scientific considerations. The risk
associated with the breach of the WHO recommendations by the MoR was however mitigated by
the consideration that a strong monitoring and evaluation system was instituted as an integral
part of the programme.
As a recommendation to researchers, longer follow-up studies should be implemented to assess
and to determine the duration and the extent at which, at community level, prevalence and
intensity of infection with S. haematobium are maintained below the threshold of heavy intensity
after a single treatment with praziquantel. This information would allow establishing the widest
possible interval of retreatment with the aim of saving as much resources and identifying the
most cost-effective disease control strategy.
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Another consideration originating from the study - from public health perspectives - is that the
substantial resources invested in the longitudinal study are unlikely to bring any additional
information significantly different from cross-sectional studies. Thus a cross-sectional survey is
more apt in terms of cost, time and energy than a longitudinal survey to provide information on
the impact a control programme.
The recommendation to officers responsible for the monitoring and evaluation component of
disease control interventions would therefore be to institute cross-sectional surveys at biennial
intervals and to include all children irrespective of educational status. This would be an indirect
verification that all children in both school and communities have actually been targeted by the
disease control intervention.
Finally for a disease that has no known animal reservoirs, it should be theoretically possible to
achieve elimination using chemotherapy. The research questions therefore are: can long-term
treatment ultimately lead to zero transmission and if so what are the requisites necessary to
achieve it? Secondly, can this goal be achieved only with high and sustained treatment coverage
rates as the research results seem to indicate? Further studies that focus on the parasite, the
human host and the intermediate host are needed to answer these questions and assess whether
preventive chemotherapy, would be capable of decreasing and finally interrupting transmission
of schistosomiasis haematobia.
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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ::s
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 'Tj [f)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ~ ........0 0 N
~
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ::s
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 'Tj [f)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ........0 0 0 0 0 0 0 0 0 0 ~ W
~
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ::s
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 'Tj
[f)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ~ ........0 0 0 0 0 .,J:::o..
0 0 0 0 ~0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 ::s0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 00 0 0 0 'Tj
[f)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ~ ........0 0 0 0 0 0 0 v-.
0 0 0 0 0 0 0 0 ~0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 ::s0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0
[f)
0 0 0 0 0 00 0 0 0 'Tj0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
University of Ghana  http://ugspace.ug.edu.gh
Available online at www.sciencedirect.com
ScienceDirect ACTA
TROPIC A
ELSEVIER Acta Tropica 99 (2006) 234-242
www.elsevier.col11/locate/actatropica
A combined school- and community-based campaign targeting all
school-age children of Burkina Faso against schistosomiasis and
soil-transmitted helminthiasis: Performance, financial costs and
implications for sustainability
Albis-Francesco Gabrielli a,*, I, Seydou Toure b,I,Bertrand Sellin c, Elisabeth Sellin c,
Cesaire Kyb, Hamado Ouedraogo ", Malachie Yaogho ", Michael D. Wilsond,
Howard Thompson a, Souleymane Sanou e, Alan Fenwick a
a Schistosomiasis Control Initiative, Imperial College London, St Mary's Campus, NO/folk Place, London W2 IPC, UK
h Programme National de LUlie contre LaSchistosomiase et les Vers lntestinaux, Minis/ere de LaSante,
06 BP9103 Ouagadougou 06, Burkina Fa.l'o
c Reseau International Schistosomoses, Environnement, Amenagements et LUlIe, Saini-Mathurin. 56270 Ploemeur; France
d Noguchi Memorial Institutefor Medical Research, University of Ghana, PO. Box LG5S!, Legon, Accra, Ghana
C Direction de la Lulie contre la Maladie. Ministere de la Sante, 03 BP7035 Ouagadougou 03, Burkina Faso
Received 23 March 2006; received in revised form 12 July 2006; accepted 27 August 2006
Available online 25 September 2006
Abstract
A combined school- and community-based campaign targeting the entire school-age population of Burkina Faso with drugs
against schistosomiasis (praziquantel) and soil-transmitted helminthiasis (albendazole) was implemented in 2004-2005. In total,
3,322,564 children from 5 to 15 years of age were treated, equivalent to a 90.8% coverage of the total school-age population of the
country. The total costs of the campaign were estimated to be US$ 1,067,284, of which 69.4% was spent on the drugs. Delivery costs
per child treated were US$ 0.098, in the same range as school-based only interventions implemented in other countries; total costs
per child treated (including drugs) were US$ 0.32. We conclude that a combined school- and community-based strategy is effective
in attaining a high coverage among school-age children in countries where school enrolment is low and where primary schools
cannot serve as the exclusive drug distribution points. The challenge for Burkina Faso will now be to ensure the sustainability of
these disease control activities.
© 2006 Elsevier BV All rights reserved.
Keywords: Burkina Faso; Schistosomiasis; Soil-transmitted helminthiasis; Control; Performance; Financial costs; Sustainability
1. Introduction
* Corresponding author. Present address: Preventive Chemotherapy The National Schistosomiasis and Soil-transmitted
and Transmission Control (PCT), Department of Control of Neglected helminthiasis Control Programme (Programme National
Tropical Diseases (NTD), World Health Organization/Organisation de Lutte con.tre La Schistosomiase et les Vers lntestinaux,
Mondiale de la Sante, 20 Avenue Appia, CH-1211 Geneva 27, Switzer-
land. Tel.: +41 2279 11876; fax: +41 2279 14869. PNLSc) was set up in June 2002 by theMinistry of Health
E-mail address: gabricllia@who.int(A.-F. Gabrielli). (MoH) in Burkina Faso to coordinate control activities
I Equally contributed to the present work. against these infectious diseases.
0001-706X!$ - see front matter © 2006 Elsevier BV All rights reserved,
doi: 10.1I) 16!j.actalropica.201)6.08.008
University of Ghana  http://ugspace.ug.edu.gh
A.-F Gabrielli et al. / Acta Tropica 99 (2006) 234-242 235
With financial and technical support from the Bill and Ziga, and in conjunction with field-based surveys (Sey-
Melinda Gates Foundation through the Schistosomia- dou Toure, personal communication).
sis Control Initiative (SCI), the PNLSc was officially In 2004, in the knowledge that schistosomiasis is
launched in May 2004. widespread across the whole country and that assessing
The mainstay of the World Health Organization the transmission status of each single community would
(WHO) recommended strategy against schistosomia- have unreasonably delayed disease control activities, the
sis and soil-transmitted helminthiasis is morbidity con- MoH with SCI's support decided to offer praziquantel
trol through chemotherapy. At the 2001 World Health free-of-charge to all school-age children living in Burk-
Assembly, Resolution 54.19 was passed which urged ina Faso irrespective of their place of residence.
member states to attain a minimum target of regular Since planning for a large-scale praziquantel dis-
administration of chemotherapy to at least 75% of all tribution programme was already underway, consider-
school-age children at risk of morbidity by 2010 (WHO, ing the occurrence of several foci of transmission of
20(2). soil-transmitted helminthiasis dispersed throughout the
The MoH of Burkina Faso endorsed this strategy and country, and the cost effectiveness of adding another
goal and currently offers treatment with praziquantel and (low-cost) product, albendazole was also added to the
albendazole, free of charge, to all children from 5 to 15 package.
years of age living in endemic areas. The aim of this paper is to describe the modalities,
Burkina Faso is a land-locked country in West Africa. analyse the performance as well as thc financial costs,
Two forms of schistosomiasis (urinary schistosomiasis and highlight the implications for sustainability, of the
caused by Schistosoma haematobium and intestinal nationwide campaign implemented in 2004 and 2005
schistosomiasis caused by S. mansonii are present by the Ministry of Health of Burkina Faso to distribute a
in the country. As far back as 1957, it was believed dose of praziquantel and albendazole to the entire school-
that the whole territory of what is now known as age population (5-15) of the country.
Burkina Faso, constituted a single, vast area endemic
for schistosomiasis (Marill, 1(57). Several subsequent 2. Materials and methods
studies have confirmed that no region of the country is
free of transmission, and the prevalence and intensity of Burkina Faso is divided into 13 administrative
infection are frequently high (as reviewed by Pod a et al., regions. There are approximately 3.65 million school-
2004). age children (5-15 years old) out of a total of nearly 13
Field surveys investigating the geographical dis- million residents (Ministere de la Sante, 2004, 2005)
tribution of schistosomiasis within the country and The MoH implemented a two-phase campaign: the
its prevalence, intensity and morbidity among school- first phase took place in October 2004 in four regions
age children were conducted in the framework of the (Boucle du Mouhoun, Nord, Sahel and Sud-Ouest) to
monitoring and evaluation activities of the PNLSc in reach a target population of over 1.1 million; the second
early 2004. Such surveys have confirmed that urinary phase took place in October 2005 in the remaining nine
schistosomiasis is intensely transmitted in all three regions, to reach a target population of over 2.5 million.
ecological zones of the country (Sahelian, Sahelian- The whole national territory was therefore targeted in
Sudanese and Sudanese), while intestinal schistosomi- the space of 1 year.
asis is mainly transmitted in the southernmost Sudanese The strategy was the same for the two phases. In both
zone. The same surveys have also shown that foci of 2004 and 2005 the MoH dedicated a week in October to
soil-transmitted helminthiasis transmission are scattered the treatment campaign. This meant that its entire staff,
throughout the country; prevalence and intensity are usu- at regional, district and dispensary level were mobilized
ally low, but isolated areas of intense transmission do to implement the campaign.
exist (MoH/SCI, unpublished data). Such baseline data, Burkina Faso has a low school enrolment rate (the
collected before the implementation of the campaign, primary school net enrolment rate in 2002-2003 was
will provide a tool to evaluate the impact of disease con- 36% (UNESCO, 2(06». The population is also widely
trol activities, through monitoring of prevalence, inten- dispersed over the territory, with a high percentage of
sity and morbidity due to both forms of schistosomiasis people living in villages (in 2003 the urban popula-
and soi l-transmitted helminthiasis. tion was just 17.8% of the total; UN, 20(4). Treatment
In the past small-scale treatment interventions were was therefore planned both through the communities and
sporadically implemented, especially in areas around through the schools. Wherever possible, the school chan-
major irrigation schemes, such as Bagre, Sourou and nel was used with the advantage that the teachers could be
University of Ghana  http://ugspace.ug.edu.gh
236 A.-F Gabrielli et al. / Acta Tropica 99 (2006) 234-242
fully involved in drug administration. Community-based from the capital Ouagadougou to regional directorates of
drug distribution teams were also used with both mobile health, where health district staff picked up their share.
and fixed units. The "passive" strategy represented by Dispensary-based staff were responsible for collecting
the school-based component (targeting schoolchildren at drugs from their nearest health district office. The num-
school) was therefore coupled with an "active" strategy ber of tablets for each region, district and dispensary
represented by the community-based component (the were calculated using national census data taking into
health worker or the community drug distributor sought account the current population growth rate (Ministere de
out those children not attending school, often living in la Sante, 2004, 2005). The targeted number of children at
remote villages or hamlets in the bush). school was based on enrolment registers kept by school
In both the schools and the communities, treatment masters; the targeted number of children in the commu-
was co-ordinated and supervised by the MoH staff based nity was calculated subtracting school population from
at each dispensary (the head of the dispensary - a reg- the updated census data.
istered nurse - plus a few health workers). The remu- Preparation activities started well before the actual
neration of the whole dispensary team - irrespective of implementation of the campaign: drugs and equipment
its size - was 10 FCFA (US$ 0.018) per target child. such as dose poles for administration of praziquantel
Responsibilities of the dispensary team included treat- were ordered about 4 months prior to the implementa-
ment of children at the dispensary (which served as a tion of each phase of the campaign. At the same time, an
fixed treatment point), and organization, coordination information and communication strategy was launched
and mobilization of teachers to treat their pupils, as at different levels. A traditional wrestler was hired for
well as of community drug distributors to reach the non- a television spot which was broadcast in French and in
enrolled chi ldren. School teachers were not remunerated seven different national languages on the national tele-
as school health is listed among their duties; community vision channel (RTB). Similar messages were broadcast
drug distributors were remunerated by their own com- by national and local radio stations, and were passed
munities through the Comites de Gestion (management on by public criers and religious as well as traditional
committees) in charge of establishing health policies authorities to inform populations and communities
and drug priorities at dispensary level. The total num- about the campaign, and to ensure compliance with
ber of community drug distributors was estimated to be treatment.
16,000, and their average remuneration was 1000 FCFA Meetings and workshops to plan the modalities of the
(US$ 1.8) per person for the entire duration of the cam- treatment campaign were held at the regional and district
paign. Health districts contributed to the campaign from levels, and were attended by Ministry of Health and Min-
their own budgets providing funds for the fuel needed istry of Education staff, and by other partners involved
to reach the scattered communities. Such contribution in deworrning, such as local non-governmental organi-
was calculated based on a 15 km journey (on average) zations (NGOs). Training sessions for trainers, health
per community drug distributor at a cost of 40 FCFA workers, community drug distributors and school teach-
(US$ 0.073) per km, ers, regarding the epidemiology of schistosomiasis and
Drugs were administered following WHO recom- soil-transmitted helminthiasis, benefits and side-effects
mendations: a dose-pole (Montresor et al., 2001a) was of treatment, dose determination, record keeping and the
used for praziquantel tablets (600 mg). Each boy or girl exclusion criterion for albendazole were organized at
also received a single tablet of albendazole (400 mg), the regional, district and dispensary levels. Health and
except when the exclusion criterion for such drug education officers in charge of each district were first
was met, namely "detection of pregnancy in the first trained at regional level; subsequently, they were asked
trimester" (based on recall of the last menstrual period) to train sub-district Icvcl officers (heads of dispensaries
(Chippaux et al., 1995). Actual swallowing of the tablets and school-masters); in turn sub-district level officers
by targeted children was directly observed by those dis- were in charge of training community drug distributors
tributing drugs. and school teachers. In total, approximately 22,000 peo-
Drugs were purchased both on the national and ple were trained throughout the country. Such activities
international market. When quotations were competi- were facilitated by the use of training manuals developed
tive preference was given to the National Drug Purchase by the PNLSc coordination team.
company (CAMEG), in order to favour sustainability of During the campaign, standardized monitoring forms
procurement activities. Three million tablets of prazi- were completed by those distributing drugs to record
quantel were donated to the country by international the numbers treated and other key data. These forms
donors through the SCI. Drugs were transported by lorry were subsequently summarized and transmitted to the
University of Ghana  http://ugspace.ug.edu.gh
A.-F Gabrielli et al. / Acta Tropica 99 (2006) 234-242 237
next hierarchical level and from there up to the national
PNLSc coordination team. ~ & ~--: 0! 00
("10 6
Children experiencing side-effects following treat- 0\ 0\ 0\
ment were looked after by the same individuals respon-
sible for treatment, who had been taught how to reassure c-
chi ldren and their families of the transient nature of such Ec
events. In case side-effects could not be managed by such E" ~ cf t§2o r: '""""r:--.
first-line personnel, children were referred to the nearest U M <n r--0\ 00 00
dispensary for medical care. No serious adverse experi-
ences (events that are fatal, life-threatening, disabling, or "beO a
incapacitating or that result on hospitalization after drug " & tf &2o> .so: r-- 01 ~o
intake) were reported. U 0\ 00 If)VJ 00 0\ 0\
Treatment activities were supervised by national- or-- r-. -er<n \0
regional- and district-level staff who visited all the 0_ lf1 tnr-- lr) 01
('I 0\ N
dispensaries 111 the target area during the campaign. o 01 ~,......N:.~ M
Dispensary-level teams visited most of the schools and
villages located in the geographical area under their
responsibility, and joined the treatment teams to verify
that correct procedures were being followed.
0\ r--
if] \0
3. Results ~0\-r0:: q
M \0
In total, 1,027,007 school-age children (5-15 years \0" I00""," n
old) were treated during the first phase of the campaign r"-:' 0r-\. r-:'
(October 2004) and 2,295,557 during the second phase M<"'l "\0 000\
(October 2005), making a total of 3,322,564 children
treated or 90.8% of the estimated school-age popula-
tion of Burkina Faso. In total 39.9% of the children
were reached through the schools and 60.1 % through
the community. The school coverage rate was 95.6%, M M \001 r-- 0\
o:::t C"I \D~
the community coverage rate was 87.7%. Overall, 1,713, ~rf")- r-.if]" 0\
.--..q- In
842 males (51.6% of the total) and 1,608,722 females
(48.4% of the total) received treatment. Further details
are presented in Table I. The number of school-age girls
0\ rf") (""'-I
excluded from treatment with albendazole due to their -0 - r> 0\(".1 7 \0o
ineligibility (meeting of the exclusion criterion) is not ..c In,_ 0" 0\ \"l 01VJ ~ if] r--
known, since only treated individuals were recorded on
\0 00 "1-
the forms provided. ("1 - Inrf")~ 0; N
Delivery costs (defined as the total campaign costs In \"l 0\b"O ~e ~
" if] \<0n
minus the drug costs) of the two rounds of treat- .: 01 t<l<1)
>
ment amounted to US$ 325,936; drug costs were oU
-0
US$ 741,348. Total costs were US$I,067,284. Cee c-
Delivery costs per child treated were US$ 0.098 'cc
(USS 0.084 for the school-based component; US$ 0.107
o"E
for the community-based component). Total costs U
per child treated (including drugs) were US$ 0.32
(US$ 0.308 for the school-based component; US$ 0.330
for the community-based component). o
The cost of each activity at the different admin- .~'"-a
istrative levels is shown in Table 2 and summarized 0.o
0.
in Tables 3 and 4. This cost-analysis includes any
"if]
financial transaction related to the implementation of 0000'" 0'
University of Ghana  http://ugspace.ug.edu.gh
238 JI.-F Gabrielli et al. / Acta Tropica 99 (2006) 234-242
Table 2
Financial costs of the campaign (in US$)
Administrative level of resource allocation Budgetary line Cost (US$)
Delivery costs'A
National level Coordination; planning; supervision; drug clearance, handling and 40,438
allocation; equipment allocation
Social mobilization 14,539
Capital equipment (dose poles, buckets, cups, etc.) 19,266
Subtotal (national level) 74,243
Regional level Coordination; planning; supervision; allocation of drugs and 9,815
equipment
Training of trainers 10,178
Social mobilization 4,906
Subtotal (regional level) 24,899
District level Coordination; planning; supervision; allocation 01' drugs and 35,022
equipment
Training of trainers/implcmenters 25,445
Social mobilization 4,906
Subtotal (district level) 65,373
Dispensary level Coordination; planning; supervision; equipment allocation J 1,170
Remuneration for distribution (MoH staff) 65,201
Remuneration for distribution (community drug distributorsj'' 29,079
Fuel for community drug distributors'r 17,448
Training of implernenters 15,266
Social mobilization 3,257
Subtotal (dispensary level) 161,421
Total delivery costs 325,936
Drug costs"
8.721,731 tablets of PZQ600mg at the 654,130
average cost of US$ 0.075/tabletD
3,488.693 tablets of ALB400mg at the 87,218
average cost of US$ 0.025ltablet
Total drug costs 741.348
Total costs of the campaign (delivery + drugs) 1,067,284
(*) Originally expressed in FCFA (Francs de la Communaute Financiere Africainey; applied exchange rate: FCFA 550 =US$ I; (A) covered by
extra-national funding (SCI) except where specified by (B) or (C); (B) covered by community contributions; (C) covered by national budget (through
district budget); (D) 3 million of the 8,721,731 PZQ tablets were donated to SCI by Medl'harm Pharmaceutical Products, VA, USA and World
Health Initiatives. Ontario, Canada.
Table 3
Expenditures by activity (in US$)
Activity Budget %
Table 4
Coordination; planning; 116,445 10.9 Allocation of resources by administrative level (excluding drugs), in
supervision; equipment US$
allocation and others Administrative level Budget %
Capital equipment 19,266 1.8
Social mobilization 27,608 2.6 National 74,243 22.8
Training 50,889 4.8 Regional 24,899 76
Drug distribution 111,728 10.5 District 65.373 20.1
Drugs 741,348 69.4 Dispensary 161,421 49.5
Total 1,067,284 100.0 Total 325,936 100.0
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A.·F. Gabrielli et al. / Acta Tropica 99 (2006) 234-242 239
the campaign at any administrative level and takes into et al., 2001 b), the majority of the non-enrolled school-
account activities supported by the national budget age children shared households with a school-going
(through the district budget), by the SCI budget and child. The Burkina Paso MoH adopted a combined strat-
by community contributions; the donated drugs were egy in which distribution channels were kept distinct:
also included at market cost. Our cost-analysis does not school teachers were responsible for treating enrolled
take into account unpaid days of labour for individuals children at the schools, and community drug distributors
involved in the campaign (such as teachers), or other for reaching all those not attending school. Results
costs related to the regular functioning of the PNLSc of such a combined approach, tested on a national
- mainly covered by the national budget - such as scale, are encouraging, as reported coverage rates were
salaries. high both for the school (95.6%) and the community
Although the period officially dedicated to the cam- (87.7%) components. As reflected in the estimated
paign was I week, a few scattered drug distribution primary net enrolment rate (higher for males than for
activities continued over the following days in those females), 54.9% of those treated at school were males
villages or schools that could not have been properly and 45.1 % were females; on the contrary, more females
targeted during the campaign due to di fficulty of access, than males were treated in the community (50.6% and
insufficient number of tablets allocated, or movement 49.4%, respectively). Overall, coverage in both schools
of nomadic populations. Such complementary activities and communities was high throughout the country.
were integrated into other health activities routinely car- Nevertheless, community coverage rates reported from
ried out at the district and dispensary levels in order to the major cities of Ouagadougou and Bobo-Dioulasso
. avoid extra costs. (approximately 1.2 million and 0.6 million inhabitants)
were, respectively, the lowest (61.1 %) and one among
4. Discussion the lowest (77.4%) registered during the campaign. The
fact that both cities were targeted in 2005 could explain
Burkina Faso officially received support from SCIon the lower coverage rates in the community reported
December lst, 2003, and launched its PNLSc on May during the second phase of the campaign if compared to
6th, 2004. Less than 6 months after the launch, slightly the first, when no major urban centres had been targeted.
less than one third of the country's school-age population It was widely recognized by field-based officers that
had received treatment against schistosomiasis and soil- drug distribution activities outside schools were more
transmitted helminthiasis. Twelve months later, one and difficult to implement in large cities than in villages due
a half years after the launch, almost the entire school-age to difficulties in reaching non-enrolled children (Seydou
population of the country had been given treatment. For Toure, personal communication).
its first campaign, the country has therefore fully attained
and indeed exceeded the 75% coverage goal set by WHA 4.2. Cost-analysis
Resolution 54.19.
This achievement was made possible by external Drug costs were the largest component of the over-
financial support. However, the treatment campaign was all costs. This was due to the relatively high price
only implemented by national staff using the local exper- of praziquantel compared to the price of drugs used
tise and the existing infrastructure of a country, Burkina to treat other helminthic diseases. On average, praz-
Faso, ranki ng 175th out of 177 on the Human Develop- iquantel costs US$ 0.075 per 600 mg tablet and each
ment Report (UNDP, 2005). school-age child requires 2.5 tablets, whereas albenda-
zole costs US$ 0.025 cents per 400 mg tablet and each
4.1. Performance analysis child requires just one tablet.
The campaign was characterized by a clear decen-
Several studies have stressed the need to include non- tralization of decision-making, as can be seen from an
enrolled children in deworming activities (as reviewed analysis of how the resources were allocated (Table 4).
by Olsen, 2003) and that delivering anthelminthic drugs Only 22.8% of the budget (excluding drugs) was spent at
through the school channel is unlikely to reach large national coordination level, while 69.6% was allocated
numbers of these children (Husein et al., 1996; Olsen, to the two lowest implementation levels (districts and
1998; Mafe et al., 20(5). There are a few success stories, dispensaries), that were left to decide how to make best
however they have been implemented on a small-scale use of their funds. The community-based component did
(Talaat et al., 20(0) or have occurred under specific not constitute a major additional increase in the cam-
social conditions. For example, in Zanzibar (Montresor paign budget: it amounted to US$ 46,527 (remuneration
University of Ghana  http://ugspace.ug.edu.gh
240 A.-F Gabrielli et al.1 Acta Tropica 99 (2006) 234-242
and fuel for community drug distributors), equivalent to of a nation-wide campaign, were in the same range as
14.3% of delivery costs or 4.4% of total costs. those registered by Kabatereine et al. (2006) from a dif-
ferent study carried out in three Ugandan sub-counties
4.2.1. Delivery costs in a district during the pilot phase of a combined school-
Despite the implementation of a community-based and community-based campaign distributing praziquan-
component (involving remuneration and fuel costs) and tel and albendazole (US$ 0.34). Figures from both coun-
the distribution of two drugs instead of one (involving tries are only slightly above the lowest figure indicated
additional logistical support), delivery costs per child by WHO for routine, school-based delivery of both
treated in Burkina Faso were in the same range as those anthelminthic drugs at the same time (US$ 0.2S-O.30)
registered by Sinuon et al. (200S) for the first round of (WHO, 2002).
a national deworming campaign distributing rnebenda-
zole in all primary schools of Cambodia (US$ 0.096). 4.3. Conclusion
If we take into account only the school-based compo-
nent, delivery costs in Burkina Faso were lower. On Our study shows that a combined school- and
the other hand, Burkina Faso's delivery costs (overall community-based drug distribution strategy is effec-
and for the school-based component only) were higher tive in attaining high coverage rates among school-age
than those reported by Kabatereine et a!. (2005) for children (both enrolled and non-enrolled) in countries
the school-based distribution of albendazole in Uganda where school enrolment is low and where the number
(US$ 0.040 to US$ 0.081 in di fferent districts). Data or the size of primary schools is not sufficient to justify
from the two countries may not be comparable due to the their use as the exclusive drug distribution channel. We
facts that Kabatereine and colleagues considered district- also show that implementing a community component
level costs only and included areas in their analysis where does not significantly increase the budget of a cam-
treatment activities had already been conducted the pre- paign, and that overall delivery costs per-child-treated
vious year. On this point, we agree with Sinuon et a!. of the combined school- and community-based strategy
(200S) that the delivery cost of re-treating children in implemented in Burkina Faso are comparable to those
areas where a similar intervention has already been con- of the school-based only strategy adopted by Cambodia.
ducted is reduced, because activities such as training do Schools are clearly a very cost-effective way of reach-
not need to be repeated on the same scale, and capital ing enrolled children, as shown by the lower delivery
investments (dose poles, buckets, cups) do not need to costs per child treated at school as compared with the
be re-purchased (unless damaged). It is therefore rea- community-treated child, and the average higher cover-
sonable to expect that delivery costs in Burkina Faso age rates attained through the school-based component.
will further decrease when areas treated in 2004 and Our recommendation is therefore that both distribution
2005 are re-treated, in line with what was reported dur- channels should be used in parallel to reach the maxi-
ing Cambodia's second round. Comparison of Burkina mum number of children at the lowest cost.
Faso cost-analysis with the Ugandan one is made even
more difficult by the fact that the assumption made in 4.4. Implications for sustainability
the latter was that the delivery costs for each drug (praz-
iquantel and albendazole) were equal, i.e. SO:50, and Control of schistosomiasis in Burkina Faso will con-
only data on the albendazole part were presented. We tinue to require dedicated financial SU)1)1ort due to wide
have refrained from splitting SO:SOthe delivery costs of geographical distribution coupled with high rates of
the Burkina Faso's school-based component and com- transmission.
paring with Uganda because it is our opinion that many Our study confirms that drugs constitute the most
operational costs (e.g. training and social mobilization) conspicuous budgetary line, by far exceeding delivery
are independent from the number of drugs that are dis- costs. A first, major step towards sustainability would
tributed. In other words, certain operational support costs therefore be for a mechanism to be established whereby
remain the same even if a second drug is added to the dis- praziquantel is regularly donated by manufacturers to
tribution of another, provided the distribution channels endemic countries (as is the case for albendazole and
for the two drugs are the same, as they are in this case. ivermectin [or lymphatic filariasis). A further contri-
bution to sustainability on the drug side is expected
4.2.2. Total costs (including drugs) from an increasing tendency to better coordinate some
Total financial costs (including drugs) per child of the large-scale helminthic control programmes. For
treated in Burkina Faso, calculated on the first round example, as lymphatic filariasis and schistosomiasis are
University of Ghana  http://ugspace.ug.edu.gh
A.-F Gabrielli et al. !Acta Tropica 99 (2006) 234-242 241
co-endemic in the whole of Burkina Faso, the MoH has would consequently be the gradual scaling down of
planned to stop administration of albendazole via the the campaign approach and the progressive incorpora-
PNLSc since the Global Programme for the Elimination tion of regular anthelminthic treatment into the routine
of Lymphatic Filariasis achieved a nation-wide yearly health care services. The expected lower cost of such an
coverage with albendazole and ivermectin in early 2006. approach, however, should be weighed against its per-
The investments over the past 2 years have been sub- formance in terms of coverage of the target population.
stantial. It is our opinion that a nationwide campaign Further research is needed in this regard.
achieving high coverage throughout the country is not
the only result of such investments. They have also Acknowledgments
contributed to building local competency and capac-
ity on control of schistosomiasis and soil-transmitted We are indebted to Henrietta Allen and Artemis
helminthiasis through large-scale training exercises and Koukounari for revision of the manuscript. We extend
have played a role in making these two diseases a public sincere thanks to the entire staff of the Ministry of Health
health priority in the country, thus generating a momen- and of the Ministry of Education, to burkinabe commu-
tum for helminth control that is a key contribute to nities and to all those who have contributed to the imple-
sustainability. mentation of the campaign both au Faso and abroad.
The in-country sources offunds, despite modest (dis-
trict budget contributions amounted to 1.6% of the total References
budget or 5.4% of the delivery costs, while community-
generated financial contributions were 2.7% of the total Chippaux, J.-P., Garden-Wendel, N., Ernould, J., Gardon, J.,
budget or 8.9% of the delivery costs), were nevertheless 1995. Comparaison entre differentes methodes de depisiagc des
counterbalanced by huge support from governmental grossesses au cours de traitemenrs par ivermectine a large echelle
staff and community members in terms of commitment, au Cameroun. Bull. Soc. Path. Ex. 88, 129-133.
dedication and social mobilization, all being key factors Husein, M.H., Talaat, M., EI-Sayed. M.K., El-Badawi, A., Evans, D.B.,
1996. Who misses out with school-based health programmes? A
in sustainability. study of schistosomiasis control in Egypt. Trans. R. Soc. Trop.
Burkina Faso has a long-standing experience with Med. Hyg. 90, 362-365.
large-scale public health interventions, such as vaccina- Kabatereine, N.B .. Tukahebwa, E., Kazibwc, E, Narnwangye, 1-1 ..
tion outreach and lymphatic filariasis elimination cam- Zaramba, S., Brooker, S., Stothard, .J.R., Kamenka, C .. Whawell,
paigns. Also for starting large-scale control of schisto- S., Webster, J.P., Fenwick, A., 2006. Progress towards country-
wide control of schistosomiasis and soi I-transmitted helminthiasis
somiasis and soil-transmitted helminthiasis, the MoH in Uganda. Trans. R. Soc. Trop. Med. Hyg. 100,208-215.
opted for a campaign approach as this seemed the most Kabatereine, N .. Tukahebwa, E.M., Kazibwc, F, Twa-Twa. J.M.,
appropriate way to sensitize populations to a "neglected Barenzi, J.FZ., Zararnba, S., Stothard, 1.R.. Fenwick, A., Brooker,
disease" against which control activities in the coun- S., 2005. Soil-transmitted helminthiasis in Uganda: epidemiology
try had been so far implemented on a small scale, and and cost of control. Trap. Med. Int. Health 10, 1187-1189.
Mafe, M.A., Appelt, B., Adewale, B., Idowu, ET., Akinwale, O.P.,
to achieve high coverage through a strategy "actively" Adeneye, A.K., Manafa, O.U., Sulyrnan, M.A., Akandc, O.D.,
delivering drugs to those in need and not just waiting for Omotola, B.D., 2005. Effectiveness of differ en I approaches to mass
them to report to the nearest dispensary when the dis- delivery of praziquantel among school-aged children in rural com-
ease has already produced its damage to the organism. rnuruties in Nigeria. Acta Trop. 93, 181-190.
This approach has been made possible by the consid- Mariti, F.-G., 1957. Diffusion de la bilharziose a «Schistosoma haeina-
tobiums en Haute-Volta. Bull. Acad. nat. Mcd. Paris 141,398-40 I.
erable support from the SCI, and Burkina Faso's next Ministere de la Sante, Direction des Etudes ct de InPlanification, 2004.
challenge will be to ensure that its schistosomiasis con- Annuaire Statistique 2003. Ministerc de la Sante, Ouagadougou.
trol programme is sustainable and continues to provide Ministere de la Sante, Direction des Etudes ct de la Planificarion, 2005.
chemotherapy at regular intervals, thus fully attaining Annuaire Statistique 2004. Ministere de la Sante, Ouagadougou.
the goal of Resolution WHAS4.19. Montresor, A., Engels, D., Chitsulo, L., Bundy, D.A.P., Brooker. S.,
Savioli, L., 2001 a. Development ancl validation of a "tablet pole"
In this respect, we think that countries such as Burk- for the administration of praziquantel in sub-Saharan Africa. Trans.
ina Faso, Cambodia and Uganda have optimized the R. Soc. Trop. Meet. Hyg. 95, 542-544.
campaign approach to be highly cost-effective, and have Montresor, A., Rarnsan, M., Chwaya, H.M., Arneir, H., Fourn,
achieved coupling high coverage rates and low cost per A., Albonico, M., gyorkos, r.w., Savioli, L., 2001b. Extending
child treated. Despite this fact, such an approach would anthelminthic coverage to non-enrolled school-age children using
still be unaffordable for Burkina Faso should financial a simple and low-cost method. Trop. Med. Tnt. Health 6, 535-537.Olsen, A., 1998. The proportion or helminth infections in a community
aid from external donors come to an end. In order to in western Kenya which would be treated by mass chemotherapy
achieve full sustainability, the operational way forward of schoolchildren. Trans. R. Soc. Trap. Mcd. Hyg. 92,144-148.
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Olsen, A., 2003. Experience with school-based interventions against UNESCO Institute For Statistics, (2006) Country profile: Burkina
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enrolled children. Acta Trop. 86,255-266. .en.uspx "coclc=8540 (accessed March 2006).
Poda, IN., Traore, A., Sondo, B.K., 2004. L'endemie bilharzienne au United Nations-Department or Economic and Social Affairs, 2004.
Burkina Faso. Bull. Soc. Path. Ex. 97, 47-52. Urban and Rural Areas 2003. United Nations, New York.
Sinuon, M., Tsuyuoka, R., Socheat, D., Montresor, A., Palmer, K., United Nations Development Programme, 2005. Human Development
2005. Financial costs of deworming children in all primary schools Report 2005. United Nations Development Programme, New York.
in Cambodia. Trans. R. Soc. Trop. Mcd, Hyg. 99, 664-668. World Health Organization, 2002. Prevention and Control 01' Schisto-
Talaar, M., Ornar, M., Evans, D., 2000. Developing strategies to con- somiasis and Soil-transmitted Helminthiasis, Report 01' a WHO
trol schistosomiasis morbidity in nonenrolled school-age children: Expert Committee, Technical Report Series 912, World Health
experience from Egypt. Trop. Med. Tnt. Health 4, 551-556. Organization, Geneva.
University of Ghana  http://ugspace.ug.edu.gh
Schistosoma haematobium Infection and Morbidity
Before and After Large-Scale Administration
of Praziquantel in Burkina Faso
Artemis Koukounari,' Albis F. Gabrielli,' Seydou Toure," Elisa Bosque-Oliva,' Yaobi Zhang,' Bertrand Sellin,'
Christl A. Donnelly,' Alan Fenwick,' and Joanne P. Webster'
'Schistosomiasis Control Initiative, Department of lntectious Disease Epidemiology, and 'Department of Infectious Disease Epidemiology, Faculty
of Medicine. Imperial College London. London. United Kingdom; 3Preventive Chemotherapy and Transmission Control, Department of Control
of Neglected Tropical Diseases, World Health Organization, Geneva. Switzerland, 'Programme National de Lutte Contre la Schistosomiase,
Ministcre de la Sante, Ouagadougou, Burkina Faso; 'Reseau International Schistosomoses, Environnement, Amenagement et Lutte. Saint
Mathurin, Ploemeur, France
(See the editorial commentary by King, on pages 653-5.)
Background. In sub-Saharan Africa, 112 million people are infected with Schistosoma haematobium, with the
most intense infections in children 5-15 years old.
Methods. We describe a longitudinal epidemiological study that evaluates the relationship between S. hae-
matobtum infection and associated morbidity in children before and after the large-scale administration of pra-
ziquantel for schistosomiasis and albendazole for soil-transmitted helminths.
Results. At baseline, higher intensities of S. haematobium infection were observed in children with anemia
and/or severe microhematuria, but there was no apparent association between the risk of undernutrition and
intensity of S. haematobium infection. Significant reductions in the prevalence and intensity of S. haematobium
infection I year after treatment were, however, observed. Children who benefited the most from anthelmintic
treatment in terms of increased hemoglobin concentrations were those who had anemia at baseline and those with
highly positive microhematuria scores at baseline.
Conclusions. This study suggests that even a single round of mass chemotherapy can have a substantial impact
on S. haematobium infection and its associated morbidity in children.
Improving the health of school-aged children, partic- tosomatidae still represent a significant segment of the
ularly in developing countries, has emerged as a policy global burden of illness, with -200 million people in-
priority in international health [1,2]. Over the past 2 fected and with the highest intensities in children s-
decades, significant progress has been made in im- IS years old [3]. Schistosomiasis causes granuloma for-
proving child survival, resulting in more children reach- ma tion and both reversible and irreversible damage to
ing primary school age. However, human infections the urinary and intestinal tracts [4]. Furthermore, new
with 1 of the 5 parasitic helminths of the family Schis- estimates of schistosomiasis-related disability have in-
dicated the need to reassess priorities for treating this
chronic infection in areas where it is endemic [5].
Received 9 November 2006. accepted 22 February 2007; electronically published Praziquantel has been established in several COI1-
16 July 2007 trolled trials as a safe and effective drug for the treat-
Potential conflicts of interest: none reported. ment of infection with all human schistosome species
Presented III pan: l lth International Congress of Parasitological Associations.
Glasgow. Scotland. 6-11 August 2006 [6-9]. The dramatic reduction in its price since 1990-
Financial support The Schistosomiasis Cuntrollnitiative is supported by the Bill by >90%, from US$4 to treat a person to approximate-
and Melinda Gates Foundation (grant 13122)
Reprints or correspondence: Artemis Koukounari. Schistosomiasis Control ly US$0.30-has led to the resolution of many of the
Initiative. Dept. of Infectious Disease Epidemiology. Imperial College london. S1. challenges surrounding large-scale chemotherapy cam-
Mary's Campus. Norfolk Place. Paddington. london W2 1PG. United Kingdom
(artern is.koukuuna ri@irnperial.ac.uk). paigns [10l; recently, through the Schistosomiasis Con-
The Journal of Infeclious Diseases 2007;196:65~9 trol Initiative (SCI), >20 million treatments were ad-
© 2007 by the Infectious Diseases Society of America All rights reserved
0022 ·lS99/2007 /19605-0003$15.00 ministered in 2005-2006 in 6 sub-Saharan African
001101086/520515 countries Ill, 12]. One of the primary objectives of
Schistosomiasis Control in Burkina Faso ·)lD 2007:196 (I September) • 659
University of Ghana  http://ugspace.ug.edu.gh
Table 1. Baseline characteristics of Burkinabe schoolchildren who were followed up for 1 year
or dropped out.
Followed up
Characteristic for 1 year Dropped out P
Demographic
Age. mean. years 9.8(n=1131) 11.3 (n = 686) <001
Male sex. % 55.0(n=1131) 62.0 (n = 686) .004
Parasitologic
Infected with Schistosoma haematobium, % 53.9 (n = 1124) 54.1 (n = 690) .953
Infected with S. mensoru. % 6.2 (n = 536) 5.8 (n = 432) .810
Infected with hookworm, % 6.3 (n = 556) 4.3 (n = 418) .174
S haematobium intensity, mean (SD), eggs/1 0 mL 83.6 (2292) 94.2 (2346) .728
S. mansoni intensity, mean (SD), epg 8.0 (739) 11.3 (761) .869
Hookworm intensity, mean (SDI. epg 12.5 (907) 3.3 (210) .158
Hematologic
Anemia, % 65.8 (n = 1130) 66.4 (n = 687) 390
Hemoglobin concentration, mean (SD), q/dt, 110 (1.4) 11.1 (14) .036
Nutritional status
Wasted, % 32.8 (n = 1131) 100.0 (n = 686) <001
Stunted, % 13.3(n=1131) 100.0 (n = 686) <001
Hemastix test (n = 1124) (n = 692) .460
Negative, % 50A 53.5
Trace, % 12.9 10.7
+, % 6.8 5.6
++, % 9.3 8.9
+++, % 20.6 214
NOTE. Anemia was defined (according to World Health Organization guidelinesl as a hemoglobin concentration
<11.5 g/dL for children 5-11 years old and <12.0 g/dL for children 12-14 years old. Wasting denotes reduced body
weight for height, defined as a body-mass-index z score less than -2. Stunted denotes reduced body length in
relation to a reference standard, defined as a height-for-age zscore less than -2. +, weakly positive; ++, moderately
positive; +++, highly positive; epg, eggs per gram of feces.
these SCI-supported control programs is to achieve, and hence tional Burkinabe helminth control program have been de-
also to demonstrate, a quantifiable reduction in schistosome- scribed elsewhere [J 4 J.
associated morbidity as a consequence of chemotherapeutic For the present study, parasitological and morbidity data
intervention. were collected from a cohort of J 727 Burkinabe children 6-14
The aim of the present study was to evaluate the relationship years old, randomly sampled from 16 schools before and 1 year
between Schistosoma haematobium infection and associated mor- after chemotherapy (2004 and 2005, respectively). The schools
bidity in children before and after the large-scale administration included in these surveys were randomly selected from all
of praziquantel and albendazole (against soil-transmitted hel- schools in 4 Regional Health Directorates known a priori to
minths) by the national Burkinabe helminth control program. be places where schistosomiasis is highly endemic. Details con-
A secondary aim was to identify those individuals whom one cerning sample-size calculations and cohort design have been
may predict to show the greatest improvements in nutritional described elsewhere [15, J 6J.
status and hemoglobin (Hb) concentrations after chemotherapy. Parasitological and morbidity measures. All children en-
rolled in the study were interviewed by appropriately trained
SUBJECTS AND METHODS personnel at the Ministry of Health, Burkina Faso. Ethical clear-
Control program, study sites, sampling, and cohort design. ance was obtained from the Ministry of Health and Imperial
Both Schistosoma mansoni and S. haematobium are endemic College London.
throughout Burkina Faso [13]. The SCI -supported schistoso- Stool examination. A single stool sample was collected
miasis control program was implemented during 2004 and had from each child, and 41.7 mg was processed to make duplicate
treated 3,322,564 school-aged children in the 13 regions of the Kato-Katz slides for microscopic determination of intestinal
country through October 2006. Further details about the na- helminth infection. Individual egg output was expressed as eggs
660 • JID 2007:196 (1 September) • Koukounari et al.
University of Ghana  http://ugspace.ug.edu.gh
Table 2. Health characteristics of children successfully followed up for 1 year ~2004-
2005), at baseline and after treatment.
Characteristic 2004 2005
Parasitologic
Infected with Schistosoma i1aematobium, %
(n = 1124) 53.91 (5100-56831 5.78 (442-7151
Infected with S. mansoni, % (n = 536) 6.16 (412-8191 0.19 (000-055)
Infected with hookworm, % (n = 555) 6.31 (428-8331 1.62 (057-2671
S. haematobium Intensity, mean, eggs/l0 mL 83.55 (7014-96961 0.94 (035-153)
5 mansoni intensity, mean, epg 8.04 (177-14311 0.02 (000-0071
Hookworm intensity, mean, epg 12.47 (492-2003) 0.78 (022-1341
Hematologic (n = 1131)
Hemoglobin concentration, mean, g/dL 10.97 (10.88-11051 11.2511118-1132)
Anemia 65.75 (6299-68521 61.59 15876-64431
Microhernaturie as diagnosed by Hemastix test
(n = 1124)
Negative, % 50.44 (4752-53371 89.5018771-91291
Trace, % 12.90 (1094-14861 4.89 (363-6151
+, % 6.76 (529-8231 2.31 (1.43-3191
++, % 9.34 (7.64-11041 1.07 (0.47-167)
+++, 0/0 20.55 (1819-22911 2.22 (136-3091
Nutritional status (n = 1131)
Thinness or wasting, % 32.80 (3007-35541 35.10 (3232-3788)
Shortness or stunting, % 13.26 (1129-1524) 11.85 (996-1373)
NOTE. Data are means or proportions (95% confidence intervall of children with characteristic, unless
otherwise indicated. Sample sizes are provided in parentheses for each examined outcome in the left-hand
column. Anemia was defined (according to World Health Organization gUidelines) as a hemoglobin concen-
tration <11.5 g/dL for children 5-11 years old and <12.0 g/dL for children 12-14 years old. Wasting denotes
reduced body weight for height, defined as a body-mass-Index zscore less than -2. Stunted denotes reduced
body length In relation to a reference standard, defined as a height-for-age Z sCOIe less than -2. +, weakly
positive; ++, moderately positive; +++, highly positive, epg, eggs per gram of feces.
per gram of feces, calculated as the arithmetic mean of the 2 nutritional index were calculated from Centre for Disease Con-
individual slide counts whenever these were available, trol (National Center for Health Statistics; year 2000) reference
Urine examination. One urine specimen was collected values using Epilnfo (version 2000; US Centers for Disease
from each child to determine the prevalence and intensity of Control and Prevention) [J 9].
S. haematobium infection by the filtration method. The inten- Anemia assessment. Blood samples for I-Ib concentrations
sity of S. haematobium infection was expressed as the number were obtained from each individual by the fingerprick method
of eggs per 10 mL of urine. To determine the presence and using a photometer (Hernocuc) [2u1. Anemia was defined ac-
severity of microhematuria, all urine specimens were tested for cording to World Health Organization (WHO) guidelines [21].
presence of detectable blood using urine reagent strips (Bayer Statistical analyses, Differences between dropouts and
Hernastix). The results were recorded semiquantitatively: neg- children successfully followed up were tested by univariate anal-
ative, trace hemolyzed, weakly positive (+), moderately positive ysis using a Wilcoxon 2-sample test for means and a X' test or
(++), and highly positive (+++), Fisher's exact test if there was a small value for proportions.
Nutritional assessment. Heights and weights were mea- SAS software was used (version 8; SAS Institute).
sured to determine height-for-age z scores (HAZ) and body- Hierarchical models are often applicable to modeling data
mass-index z scores (BMIZ). All measures were obtained using from complex surveys of a population, with a hierarchical struc-
height poles and electronic balances in the morning, and chil- ture used to explain relations between individual and suprain-
dren were barefoot, wearing only light indoor clothing, A low dividual determinants. A 2-1evel linear hierarchical model
BMIZ is the index of choice for the assessment of recent un- assuming normally distributed errors was fitted to the loga-
dernutrition resulting in thinness or wasting, whereas a low rithmically transformed baseline S. haematobium egg counts
HAZ represents long-term growth and nutritional status re- (In [X + l]), using Gibbs sampling for all parameters [221 to
sulting in shortness or stunting [17, 18]. z scores for each quantify any associations with anemia, measures of nutritional
Schistosomiasis Control in Burkina Faso • [H) 2007:196 (I September) • 661
University of Ghana  http://ugspace.ug.edu.gh
Table 3. Estimates from 2-level hierarchical model for Schistosoma haematobium egg counts
among 1130 Burkinabe schoolchildren at baseline and after treatment (2004-2005).
Model Coefficient (95% CI) P
Fixed effects
Effect of year 1 follow-up relative to baseline -52% (-57% to -47%) <001
Male sex (reference category: female) 11% (2% to 21%) .020
Baseline age (reference category: 14 years)
13 years 9% (-19% to 45%) .572
12 years 45% (11% to 90%) .007
11 years 25% (-4% to 63%) .095
10 years 32% (2% to 72%) .035
9 years 24% (-4% to 61%) 106
8 years 22% (-6% to 59%) .143
7 years 2% (-24% to 37%) .906
6 years 19% (-27% to 92%) 488
Baseline anemia (reference category: not anemic) 11% (1% to 21%) .026
Baseline hematuria (reference category: negative)
Trace 242% (191% to 302%) <.001
+ 462% (357% to 592%) <001
++ 1470% (1176% to 1833%) <001
+++ 4107% (3493% to 4827%) <001
Baseline thinness or wasting (reference category:
not wasted) 4% (-6% to 14%) 463
Baseline shortness or stunting (reference category:
not stunted) -13% (-26% to 2%) .089
Variance components (SE)
Random effects
Level 2 variance (between schools) 0.008 (0004)
Levell variance (measurement occasions Within a child) 0.190 (0006)
NOTE. Anemia was defined (according to World Health Organization gUldelinesl as a hemoglobin concentration
<11.5 g/dL for children 5-11 years old and <12.0 g/dL for children 12-14 years old. Wasting denotes reduced body
weight for height, defined as a body-mass-index z score less than - 2. Stunting denotes reduced body length in
relation to a reference standard, defined as a height-for-age zscore less than -2. +, weakly positive; ++, moderately
positive; +++. highly positive; CI, confidence interval.
status, and microhematuria while adjusting at the same time An additional 3-level hierarchical linear modeling analysis
for demographic factors such as age and sex. In this way, we was performed to determine any change in the children's I-Ib
tested whether children with pathology potentially induced by concentrations. With this model, we aimed to quantify the
S. haematobium infection had higher S. haematobium egg adjusted overall change in I-Ib concentration from baseline to
counts before treatment. We used a similar model to quantify follow-up and to quantify average Hb concentrations of dif-
changes in S. haematobium egg counts from baseline to 1 year ferent groups of children at baseline as well as to examine
of follow-up. Mlwin software (version 2.01; Multilevel Models whether the intensity of S. haematobium infection was asso-
Project, Institute of Education, University of London ) was used. ciated with lower Hb concentrations. Logistic random-inter-
Box plots of the S. haematobium egg counts at baseline were cepts regression models were fitted to examine whether the
used for validation and comparison of the significant findings intensity of S. haernatabium infection was associated with an
from the model described above. increased risk of thinness and shortness at baseline while ad-
Changes in Hb concentration and in HAZ and BMIZ scores justing for potential confounders.
over time were evaluated using 2-levellinear hierarchical mod-
els of raw change scores between baseline and the I-year follow- RESULTS
up time point. With this approach, we aimed to compare the
average change in each of the studied outcomes over the studied A total of 1727 children from 16 schools were recruited at
period between different groups of children. All of the models baseline. Of these, 1131 (65%) were successfully retraced at the
presented were also adjusted for age 31_1dsex. P< .05 was con- l-year follow-up time point, and 321 new children were re-
sidered to be significant. cruited into the cohort during the second year of the study
662 • JID 2007:196 (1 September) • Koukounari et al.
University of Ghana  http://ugspace.ug.edu.gh
A _ B
8
NegL-'ltjlje Truce rlfZ!molyzed
Figure 1. Box plots for the logarithmically transformed (base e) Schistosoma haematobium egg counts of positive subjects only (n = 613 Burkinabe
schoolchildren, 2004) A, Box plot for log S. haematobium egg counts with respect to different microhematuria test scores at baseline. 8, Box plots
for log S beemetobium egg counts with respect to anemia status at baseline. Data are smallest observations, lower quartiles (01 L medians, upper
quartiles (03), and largest observations. +, weakly positive; -t-t-, moderately positive; +++, highly positive.
(data not shown), There were significant differences between and a significant decrease in the prevalence of anemia (P =
the children who were successfully followed up and the drop- ,021) were also observed between 2004 and 2005. Finally, the
outs, according to their demographic characteristics and nu- unadjusted observed changes in both recent and chronic un-
tritional status as defined hy baseline thinness and shortness dernutrition from baseline to follow-up were not significant
as well as by baseline Hb concentrations (table 1), The children (P = ,135 and P = ,093, respectively).
who dropped out were of an older mean age than those suc- Table 3 presents the results of the model of the change in S.
cessfully followed up, and boys proved more difficult to recruit haematobium egg counts for I year after treatment as well as
into the cohort during the second year of the study. All children differences in S, haematobium egg counts between different
who dropped out were wasted and stunted at baseline and had groups of children at baseline, This model indicated that, com-
slightly higher mean Hb concentrations. No other baseline pared with baseline counts, there was on average an overall
characteristic measured varied significantly between children significant decrease in S. haematobium egg counts by 52% 1
followed up and those who dropped out. year after treatment (P< .001). At baseline, only children 10
Table 2 presents the health indicators of children surveyed and 12 years old had significantly higher 5, haemaiobium egg
at baseline and successfully followed up 1 year after treatment. counts, compared with those who were 14 years old (P =
During the 12 months between examinations, the overall .035 and P = ,007, respectively) after controlling for sex, nu-
prevalences of S, haematobium, S. mansoni, and hookworm tritional and anemia status, and microhematuria test scores,
infections decreased sign ificantly (P < .001). For both years ex- Children with +++, ++, +, and trace microhernaturia scores
amined, Ascaris lumbricoides infection was absent, and the prev- had on average significantly higher S. haematobium egg counts
alence of Trichuris trich ura infection was estimated to be I, I% than those of children with negative scores at baseline, by
at baseline and totally absent 1 year later. Because prevalences 4107%, 1470%,462%, and 242%, respectively. Additionally,
and coinfections with S. haematobium were so low for the children with anemia at baseline had significantly higher 5.
intestinal helminth species at both time points, such data were haematobium egg counts (by II %) than children without ane-
not analyzed further here, mia (P = .026). Rays also hac! significantly higher S, haema-
A significant increase in mean Hb concentration (P< .001) labium egg counts (by 11%) than girls at baseline (P = .020),
Schistosomiasis Control in Burkina Faso • JID 2007: 196 (I September) • 663
University of Ghana  http://ugspace.ug.edu.gh
Figure lA shows that children with the most severe micro- 1.5 times more likely than those without anemia to be stunted
hematuria scores harbored higher intensities of S. haematobium at baseline (P = .034; data not shown).
infection than children who were negative for microhematuria Table 4 contains estimates from the two 2-levellinear mul-
at baseline. Children with anemia at baseline also harbored tilevel models for changes in HAZ and BMIZ during the period
slightly higher intensities of S. haematobium infection than studied. The effect for the 14-year-old comparison group was
those without anemia (figure 1B). a decrease in BMIZ of 0.519 units, which was of borderline
Results from the 2-level logistic regression model for the significance (P = .053). This suggests that there was no dra-
probability of being wasted did not suggest associations with matic change over the period studied in this group. However,
any baseline characteristics examined other than age. In par- children who were 7, 8, and 10 years old at baseline had a
ticular, there was a trend toward younger children being less greater decrease in BMIZ, compared with 14-year-olds. The
likely to be wasted, although none of the other odds ratios coefficients of the continuous variables that refer to the baseline
(ORs), except for those for IO-year-old children, were signifi- HAZ and BMIZ scores indicated that BMIZ increased for
cantly different from the ORs for 14-year-old children (P = wasted children, whereas, BMIZ decreased for stunted children
022). Furthermore, the 2-levellogistic regression model of the more than that of children with no nutritional problems. These
probability of being stunted at baseline suggested a trend toward results can be obtained if one multiplies the coefficients ofHAZ
younger children being less likely to be stunted; the OR for 6- and BMIZ by -2 (i.e., the cutoff score that defines wasting
12-ycar-old children was significantly different fro m that for and stunting, respectively).
14-year-olds. In addition, children with anemia were almost The effect for the 14-year-old comparison group was a non-
Table 4. Estimates from 2-level hierarchical model for the change of body-mass-index z score (BMIZ) and height-for-age z score
(HAZ) (n = 1130).
Coefficient (95% CI) Coefficient (95% CI)
Model for change in BMIZ P for change in HAZ P
Fixed effects
Intercept -0.519 (-1.003 to -0035) .053 0.143 (-0.073 to 0359) 214
Baseline intensity of Schistosoma haematobium
Infection (reference category: uninfected)
Lightly Infected 0.060 (-0133 to 0253) 543 0.032 (-0059 to 0 124) 490
Heavily Infected 0.218 (-0030 to 0465) .085 0.078 (-0040 to 0196) 193
Male sex (reference category: female) 0.011 (-0 100 to 0 122) .850 -0066 (-0 119 to -0013) .015
Baseline age (reference category 14 years old)
13 years -0.120 (-0649 to 0410) .658 -0.134 (-0.388 to 0.119) .300
12 years -0.375 (-0816 to 0067) .097 -0.236 (-0447 to -0025) .029
11 years -0.396 (-0835 to 0043) 077 -0.177 (-0386 to 0033) .099
10 years -0483 (-0915 to -0051) .029 -0.008 (-0215 to 0198) .936
9 years -0.347 (-0778 to -0084) 115 0.000 (-0206 to 0206)) .999
8 years -0.448 (-0879 to -0.017) 042 0.051 (-0155 to 0257) .625
7 years -0.642 (-1083 to -0201) .004 -0033 (-0244 to 0 178) .757
6 years -0483 (-1.051 to 0085) .096 0.428 (0 157 to 0699) .002
Baseline anemia (reference category: not anemic) 0.005 (-0 114 to 0.123) .939 -0041 (-0098 to 0.015) .153
Baseline hematuria (reference category: negative)
Trace -0.166 (-0389 to 0057) .144 -0063 (-0169 to 0043) .243
+ -0.147 (-0416 to 0123) .286 -0.014 (-0142 to 0114) .829
++ 0.054 (-0208 to 0317) .685 -0027 (-0152 to 0097) .669
+++ -0.110 (-0356 to 0136) .383 -0.058 (-0174 to 0.059) .334
Baseline BMIZ -0.588 (-0628 to -0548) <.001 0.054 (0035 to 0073) <.001
Baseline HAZ 0.184 (0 135 to 0232) <.001 -0.138 (-0161 to -0115) <.001
Variance components (SE)
Random effects
Level 2 variance (between schools) 0.155 (0065) 0.009 (0004)
Levell variance (between children within a school) 0.846 (0036) 0.194 (0008)
NOTE. Anemia was defined (according to World Health Organization guidelinesl as a hemoglobin concentration <11.5 g/dL for children 5-11 years old and
<12.0 g/dL for children 12-14 years old. +. weakly positive; ++, moderately positive; +++. highly positive; CI, confidence interval.
664 • JID 2007:196 (J September) • Koukounari et al.
University of Ghana  http://ugspace.ug.edu.gh
significant (P = .214) increase in HAZ of 0.143 units. Com- peutic treatment, taking into account adjustment and nonad-
pared with 14-year-olds, 6-year-olds had a significantly greater justment for microhematuria scores. From the former model
increase, whereas the 12-year-olds had a decrease in HAZ (sig- it was estimated that an overall increase of 0.092 g/dL in Hb
nificantly different from that of 14-year-olds). Boys had a sig- concentration after treatment was not significant (P = .146).
nificantly smaller increase in HAZ than girls. Likelihood ratio Children with +++ microhematuria scores had significantly
tests indicated a better fit in both models mentioned above lower Hb concentrations (0.318 g/dL; P = .016) than micro-
when we included HAZ and BMIZ as explanatory continuous hematuria-negative children at baseline. Children who were 6,
variables and not the relevant categorical ones that would de- 7, 8, and 10 years old at baseline had significantly lower Hb
note wasting and stunting if HAZ or BMIZ was, respectively, concentrations (P = .024, P< .001, P = .019, and P = .008,
less than - 2 SD. respectively) than those who were 14 years old, after controlling
Table 5 contains the estimates of two 3-level hierarchical for intensity of S. haematobium infection, sex, hematuria, wast-
models for Hb concentrations before and after chemothera- ing, and thinness. From the alternative model, which did not
Table 5. Estimates from 3-level hierarchical models for hemoglobin concentration before and after treatment, taking into account
adjustment and nonadjustment for microhematuria scores (n = 1124).
Coefficient (95% CI) Coefficient (95% CI)
with adjustment for without adjustment for
Model microhematuria P microhematuria P
Fixed effects
Intercept 11473 (11.067 to 11879) <.001 11480 (11.074 to 11886) <001
Effect of year 1 follow-up relative to baseline 0.092 (-0031 to 0215) 146 0.093 (-0030 to 0216) 139
Baseline intensity of Schistosoma haematobium
infection (reference category: uninfected)
Lightly infected -0.107 (-0311 to 0097) .303 -0079 (-0238 to 0080) .332
Heavily infected -0.084 (-0354 to 0 186) .542 -0.220 (-0410 to -0030) .024
Male sex (reference category: female) -0.035 (-0.158to 0088) .577 -0039 (-0162 to 0.084) .538
Baseline age (reference category: 14 years old)
13 years -0.026 (-0383 to 0331) .888 -0.037 (-0396 to 0322) .838
12 years -0.136 (-0.489 to 0217) .452 -0.138 (-0493 to 0217) 445
11 years -0.334 (-0683 to 0015) .061 -0.353 (-0704to -0002) .048
10 years -0.468 (-0813to -0123) .008 -0.471 (-0818to -0124) 008
9 years -0.296 (-0643 to 0051) .095 -0.290 (-0639 to 0059) .103
8 years -0425 (-0780 to -0070) .019 -0.415 (-0772 to -0058) .022
7 years -0.817 (-1.205 to -0429) <.001 -0.816 (-1206 to -0426) <.001
6 years -0.693 (-1.297 to -0089) .024 -0.685 (-1.289 to -0081) .026
Baseline hematuria (reference category: negative)
Trace 0.108 (-0115to 0.331) .344
+ 0.135 (-0149to 0419) .352
++ 0.229 (-0 063 to 0521) 124
+++ -0.318 (-0577 to -0059) .016
Baseline thinness or wasting (reference category:
not wasted) -0.042 (-0162to 0078) 488 -0.042 (-0162 to 0078) 491
Baseline shortness or stunting (reference category'
not stunted) -0.149 (-0.351 to 0053) .148 -0.155 (-0359 to 0049) 135
Variance components (SE) Variance components (SE)
from the model with from the model without
adjustment for microhematuria adjustment for microhematuna
Random effects
Level 3 variance (between schools) 0136 (0056) 0.140 (0057)
Level 2 variance (between children within a school) 0.514 (0051) 0.519 (0051)
Levell vanance (measurement occasions within a child) 1.106 (0047) 1.116 (0047)
NOTE. Wasting denotes reduced body weight for height, defined as a body-mass-indexz score less than -2. Stunting denotes reducedbody length in
relationto a referencestandard.definedasaheight-for-agezscoreJessthan -2. +. weaklypositive;++. moderatelypositive;+++. highlypositive;CI.confidence
interval.
SchistosomiasisControl in Burkina Faso • lID 2007:196 (I September) • 665
University of Ghana  http://ugspace.ug.edu.gh
adjust for microhematuria scores, estimates of the parameters the microhernaturia scores explain some of the variability in
mentioned previously remained approximately the same, but the studied outcome across all 3 levels of the models presented.
the effect of S. haematobium infection intensity became sig- Finally, table 6 contains estimates from the 2-level linear
nificant, such that children who were heavily infected with S. multilevel model for the change in Hb concentration over the
haematobium at baseline had significantly lower Hb concen- course of the period studied. This model suggested that the
trations (0.220 g/dL; P = .024) than uninfected children. This change varied significantly as a function of the following base-
suggests that because the variable of microhematuria scores is line characteristics: anemic status, +++ microhematuria score,
related to both Hb concentration and the intensity of S. hae- and age. The effect for the comparison group (baseline unin-
matobium infection, 2 different causal effects of S. haematobium fected, male, 14 years old, not anemic, negative microhematuria
infection on Hb concentrations are indicated. Two-way inter- score, not wasted, and not stunted) was a decrease in I-Ib con-
action terms were also tested, but because they were not sig- centration of 0.128 g/dL, which was not significant (P = .747).
nificant, they were omitted from the models presented. Also, Significant increases in Hb concentration during the period
variances in all 3 levels of the second model were higher than studied were observed among children with anemia at baseline
the corresponding ones in the first model, which implies that (increase by 1.360 g/dL [that is, 1.488-0.128 g/dl.]; P< .001)
Table 6. Estimates from a 2-level hierarchical model for changes in hemoglobin concentration
(n = 1130).
Model Coefficient (95% Cl) p
Fixed effects
Intercept -0.128 (-0888 to 0633) .747
Baseline intensity of Schistosoma haematobium infection
(reference category: uninfected)
Lightly infected -0.081 (-0350 to 0187) .553
Heavily infected -0.258 (-0602 to 0086) .141
Male sex (reference category: femalel 0.050 (-0105 to 0.2051 .529
Baseline age (reference category 14 years old)
13 years -0.625 (-1364to 0114) .097
12 years -0.605 (-1.222 to 0.013) .055
11 years -0.435 (-1049 to 0179) .165
10 years -0.464 (-1.067 to 0140) .132
9 years -0.719 (-1321 to -0.117) .019
8 years -0.284 (-0886 to 0.318) .355
7 years -0.139 (-0753 to 0.475) .657
6 years -0.788 (-1.575 to -0002) .050
Baseline anemia (reference category: not anemic) 1488 (1.323 to 1653) <.001
Baseline hematuria (reference category: negative)
Trace 0.106 (-0.204 to 0.415) .b04
+ -0.029 (-0404 to 0345) .878
++ O.OlD (-0354 to 0375) .955
+++ 0.361 (0019 to 0.702) .039
Baseline thinness or wasting (reference category:
not wasted) -0.057 (-0226 to 0 112) .506
Baseline shortness or stunting (reference category:
not stunted) 0.004 (-0225 to 0234) .971
Variance components (SE)
Random effects
Level 2 variance (between schools) 0.123 (0062)
Levell variance (between children within a school) 1.647 (0070)
NOTE. Anemia was defined (according to World Health Organization guidelines) as a hemoglobin concentration
<11.5 g/dL for children 5-11 years old and <12.0 g/dL for children 12-14 years old. Wasting denotes reduced body
weight for height. defined as a body-mass-index z score less than -2. Stunting denotes reduced body length in
relation to a reference standard. defined as a height-far-age z score less than -2. +. weakly positive: ++. moderately
positive: +++. highly positive; CI, confidence interval.
666 • lID 2007:196 (I September) • Koukounari et al.
University of Ghana  http://ugspace.ug.edu.gh
and among children with +++ microhematuria scores at base- maturia-which, as demonstrated previously (Tohon Z, Bou-
line (increase by 0.233 g/dL [that is, 0.361-0.128 g/dl.], P = bacar Mainassara H, Elhaj Mahamane A, et aI., submitted) [29),
.039). Marginally significant decreases in Hb concentration dur- is associated with S. haematobium infection-can be an im-
ing the same period were observed in children who were 12 portant cause of blood and iron loss, which also may lead to
years old at baseline; these children had a greater decrease, by anemia. Our data suggest significant reductions in the preva-
0.733 g/dL (that is, -0.605-0.128 g/dL; P = .055), in Hb con- lence and, more importantly, intensity of infection of S. hae-
centration than 14-year-old children. In addition, 9-year-old rnatobium as well as in the percentages of children with positive
children had a significantly greater decrease in Hb concentra- microhernaturia scores 1 year after treatment (tables 2 and 3).
tion, by 0.847 g/dL (that is, -0.719-0.128 g/dL; P = .019). The children who most benefited from anthelmintic treat-
ment in terms of increased Hb concentration were those with
DISCUSSION anemia at baseline and those who had +++ microhematuria
scores at baseline (table 6), which confirms similar findings
Among the different schistosomes infecting humans, S. hae- presented elsewhere [30, 31]. The mechanisms by which treat-
rnatobium is responsible for the largest number of infections. ment for S. haematobium infection allows Hb concentrations
It has been estimated that, in sub-Saharan Africa, 112 million to increase in children with anemia may be the decrease in
people are infected with S. haematobium, compared with 54 blood in urine that results from a reduction in the intensity of
million infected with S. rnansoni [23]. However, S. haemato- S. haematobium infection [32].
bium remains largely unstudied, particularly in comparison to Growth and nutritional status have been proposed to rep~
S. mansoni, primarily because of the more demanding condi-
resent the most sensitive indicators of health in children [33].
tions for its laboratory maintenance. This is also reflected in
Furthermore, one of the factors emphasized in the World De-
the paucity of research examining the potential effectiveness of
velopment Report 1993 is the relationship between parasitic
praziquantel against S. haematobium under various experi-
infections and malnutrition [2]. We examined whether greater
mental and clinical circumstances [24]. To our knowledge, the
S. haematobium egg counts were associated with increased risks
present study represents the first longitudinal study in Africa
of wasting or stunting at baseline, adjusting for demographic
that reports on the relationship between S. haematobium in-
characteristics and other potential predictors such as micro-
fection and its associated morbidity as a whole, by use of a
hematuria and anemia status. The results of this study did not
uniquely detailed large data set from 16 randomly selected
suggest any significant association between the risk of under-
schools across the entire national territory of Burkina Faso.
nutrition and intensity of S. haematobium infection, with only
Moreover, these data have the potential to provide important
evidence characterizing urinary schistosomiasis-associated mor- age being revealed as a signilicant factor. Younger children
bidity, particularly in a population such as that of Burkinabe, tended to be less likely to be wasted or stunted than 14-year-
where the prevalence of hookworms and other soil-transmitted old children, which could imply prior malnutrition in these
helminthiasis is estimated to be very low. Although previous older children, as has been reported elsewhere [I]. In the afore-
studies have tended to focus on the impact oflarge-scale control mentioned study, the authors also reported that, in Zanzibari
programs on intense transmission of S. haematobium infection boys, the association between microhematuria and poor growth
with regard to Hb concentrations and anemia only (Tohon Z, was only marginally significant [1], which is in line with our
Boubacar Mainassara H, Elhaj Mahamane A, et aI., submitted) findings that, in the Burkinabe children, changes in the BMIZ
[25], to parasitological measures only [26, 27], or to S. hae- scores depended only on age, whereas changes in the I-IAZ
matobium morbidity indicators before and after treatment [28], scores depended on age and sex (table 4). A more plausible
the present study examined all these issues together and also explanation for the lack of statistical association between the
adjusted for potential differences in demographic characteristics intensity of S. haematohium infection and stunting may relate
as well as potential confounders. to dropout bias toward stunted children (table 1); this means
We have demonstrated that children with anemia or children that it is difficult to make a definitive conclusion regarding the
with more severe microhematuria scores at baseline had higher relationship between urinary schistosomiasis and stunting in
S. haematobium infection intensities (table 3 and figure I), our study population [34].
which suggests that heavy intensities of S. haematobium infec- Nevertheless, it must be considered that essential method-
tion can be associated with anemia and hematuria. We also ological constraints inherent in the present study design-in
provide evidence that heavy infections of urinary schistoso- particular the lack of a control group, which was necessary for
miasis are associated with lower Hb concentrations and, as a ethical reasons, could result in some potential bias toward the
consequence, with potential anemia, given that the models in estimation of the absolute impact of the treatment, thereby
table 5 indicate that S. haematobium infection might be asso- allowing only the relative impact of the treatment in different
ciated with anemia in 2 different ways. More precisely, he- groups of children to be calculated. However, even though these
Schistosomiasis Control in Burkina Faso • JID 2007:196 (I September) • 667
University of Ghana  http://ugspace.ug.edu.gh
data were obtained from a large-scale control program and stud- 10. Larnmie Pl, Fenwick A, Utzinger J. A blueprint for success: integration
ies such as ours are generally difficult to execute in terms of of neglected tropical disease control programmes. Trends Parasitol
2006; 22:3 I 3-21.
design, methodology, and sampling, we believe that the results II. Garba A, Toure S, Dernbele R, Bosque-Oliva E, Fenwick A. Implc-
will be of substantial value in estimating the total benefit that mentation of national schistosomiasis control programmes in West
control of schistosomiasis can provide to communities [351. Africa. Trends Parasitol 2006; 22:322-6.
12. Kabatereine NB, Fleming F, Nyandindi U, Mwanza ]CL, Blair L. The
This study shows that praziquantel can have a substantial control of schistosomiasis and soi.transmitted helminths in East Africa.
impact on S. haematoin um infection and associated disease Trends Parasitol 2006; 22:332-9.
when delivered as part of a large-scale control program in a 13. Poda IN, Traore i\, Sondo BK. L'endernie bilharzienne au Burkina
country such as Burkina Faso, which was the first country in Faso. Bull Soc Pathol Exot 2004; 97:47-52.
14. Gabrielli AF, Toure S, Sellin B, et al. A school- and community-based
the WHO African Region to achieve nationwide coverage with campaign targeting all school age children of Burkina Faso against
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Acknowledgments and Prevention 2000 growth charts for the United States: improve-
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We extend our sincere thanks to the schoolchildren, teachers, and com- diatrics 2002; 109:45-60.
munity members who participated in the study and the staff of Institute
20. Parker DR, Bargiota A, Cowan FG, Corral! RJ. Suspected hypoglycae-
de Recherches Scientiliques de Sante and Centre National de la Recherche
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Scientilique et Technologique in Burkina Paso, We particularly thank Ha-
Ky, Endocrinol (Oxl) 1997;47:679-83.mada Ouedraogo, Cesaire and Malach ie Yaogho for their contribution.
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Schistosomiasis Control in Burkina Faso • JID 2007:196 (I September) • 669
University of Ghana  http://ugspace.ug.edu.gh
Seydou Toure,3 Yaobi Zhang,b Elisa Bosque-Oliva,' Cesare KY,3Amaoo Oueciraogo,3 Artemis Koukounari,h
Albis F Gabrielli,c Bertrand Sellin,d Joanne P WebsterO & Alan Fenwlckl)
Objective To evaluate the impact all sclustosorntasis of blennial treatment with praziquantel (PZO) among school-age children in
Burkina Faso, tile first country that achieved full national coverage with treatment of more than 90%, of tile school-age population.
Methods A cohort of 1727 schoolcbildren (6-14 years Old) was monitored at yearly intervals through a longitudinal survey. Additional
groups of scboolcbmren were monitored in cross-sectional surveys. Parasitological examinations for Schistosoma haematobium and
Scl7istosoma mansonivvere performed, and prevalence and intensity of infection before and after treatment were analysed.
Findings Data from the longitudinal cohort show that a single round of P70 treatment significantly reduced prevalence of S. haematobium
infection by 87% (from 59.6% to 7.7%) and intensity of infection by 92.8% (from 94.2 to 6.8 eggs/10 rnl of urine) 2 years post-
treatment. Tile impact on infection was also contrmed by a cross-sectional survey 2 years post-treatrnent.lmportantly, tile proportion
of school-age children with heavy S. haematoiJium infection decreased from around 25°;(, before treatment to around 2-3% 2 years
post-treatment. Cross-sectional comparison of S. haematoiJium infection in 7 -year-old cbildren in their first year at school, who received
treatment through community-based drug delivery, also showed significant reduction in both prevalence (65.9%) and intensity of
S. 178ema/obium infection (78.4%) 2 years after single treatment. 1\ significant reduction in S. mansorli infection was also achieved.
Conclusion Significant ami sustained reduction in S. iJaematobium infection was achieved by biennial treatment in school-age
children in Burkina Faso. This may provide a cost effective treatment strategy for similar national schistosomiasis control programmes
in sub-Saharan Africa.
Bulletin of the Worlel Heaith Organization 2008;861BO-!8!.
Une traduction en !ran~'ais rje ce resume ligwe it fa fin de ra!le/e, l\f final de! a:tfc;io Sf, f:;cHita una tr8r)uccfon ai IdSJX!!!O! .6J\.Ul ~41 ~1SJ1 ,.p;J\ 4..:.~ ~ a...o~l ~41 ~rzlj ~jJ\
Introduction aim ofrnorbidiry control is to reduce in-· on urinary schistosomiasis through
tensity of infection by drug treatment. borh 5c11001- and community-based
Two main forms of human schistosomi- Several national control pL'ogrammes drug deliveries for school-age children
asis or bilharzia exist in Africa··· urinary on schistosomiasis and soil-transmitted in Burkina Faso ill western Africa.
schistosomiasis caused by Schistosoma
helminthiasis (5TH) are now being Burkina Faso is a land-Iocked
haematobium infection and intestinal
implemented across sub-Saharan Africa country in western Africa with a total
schisrosorniasis caused by Schistosoma
mansoni with financial and technical supportinfection. lhcrc arc around population of about 13 million. of
165 million people in sub-Saharan from the Schistosomiasis Cont.rol which approximately 3.65 million are
Africa with the disease: about 112 l nit iat ive." We have previously re- school-age children. II S. haematohium
million with urinary schistoso miasis ported the successful implemenrarlon is the main species prevalent through-
and about 54 million with intestinal of the national control programme on out the COUntry with focal. prevalence of
schistosomiasis.'··' The rnainsray of inresrinal schistosomiasis and 5TH us .. LIp [0100%, while S. mansoni is prescm
the currCH( strategy recommended. by ing annual rrearrnent strategy through mainly in the southern and western
\X'HO agai.nst schist.osomiasis is mor .. sc1lOoJ ..based drug delivery for school- regions.'2 50rne small-scale control ac-
bidity conrrol through pr('ventive che- children and communi t:y-based drug tivities with rreatment had taken place
motherapy with praziquamel (PZQ) .,.j delivery fOf' adults at high risk, and in some arc-as in rhe past,' 1.13 bur rhe na-
5chisrosorne morbidity is mainJy clllsed the great impact achieved on reducing tional. control programme did not start
by eggs trapped in various parts of the morbidity and infection in Uganda in until 2004. Full national coverage of
human body, depending on rhe species easr.ern Africa.~)·") \Ve now repOfT the trealrnenrwas achieved in 2005. A total
ofschistosornes. hence the flll1damental impact. of biennial [rca[men t strategy of more tbn 3.3 million school-age
, Programme National do Luna contro ia ScilistosofTliaso ot ies Vers IntoslirlaUx. M;nistore do 1<1Sante, Ouagadougou. Burkina Faso.
" Scilistosomiasis Controllnitiatv0.impefial Coiiege Lmdon. Norfolk Placo, Loncion. W2 iPG. England.
, Depal1ment of Control of Negiectecl Tropical Diseases, Wo:-Id Health Or(pnization. Geneva, Switzerland
d Reseau International Scl'l!stosornoses, Environnerrwilt, J.\menaqernents et Lutte (RISEAL), Ploemeur, FI'Clm;e,
COI'respolldence to YaoLii Z!!ano (e-rilai!: yaobi.zlJanOCq)irnpet'ial.ac.uk).
dOll 0.;'471 !BLI07. 048694
(SuOmi/ted: 18 Oclober 200l-·· F!evised vlH'sion received: 7 July 2008- Acceptod: 8 July 2()08 ...Published online.' 25 August 20(8)
780 Eluiietn of lile World Healt!l Orqanizalion October 2008. 86 (10)
University of Ghana  http://ugspace.ug.edu.gh
Research i
children received their first treatment, been described elsewhere. ,",16 Briefly, Research Ethics Committee of Sr Mary's
representing 90.8l}o of the estimated overall sample size was calculated with Hospital, London, as well as approval
school-age popul arion in the cou n rry. I I an expected reduction of70i)i, in mean hom the Ministry of Health of Burkina
Our results at: one year post-treat.ment" intensity for S. baernatobium over a Faso, Written informed consent was
showed that. trcarrncn t significan dy 2-year period using the EpiSchisto obtained from head teachers at each
reduced infection and morbidity by software tool (available at: http://www. school wirh prior agreements from par-
S. baematobium." The curren t. paper schoolsandhcalth.org). An overall drop- ents or guardians,
presents the parasitological impact of out: rate of 40% over the course of the
a single treatment on schistosomiasis monitoring period was also allowed. d
2 years after treatment. Sentinel schools were randomly selected Urine examination
from all schools in four priority regions
One urine specimen was collected from
Methods rarget.ed in 2004. \\7ithin each school, each child to determine 5;, haematobium
ISO children were selected randomly infection using the filtration method
frOITI each of the 7.., S- and ll-year-
and microscopy. Generally; specimens
Deruils about the national schisroso- old grollps with approximately equal were collected around noon (between
rniasis control programme supported numbers of boys and girls in each age approximately 10:00 and 13:00), 10 ml
by the Schistosomiasis Control. Ini- group. However, due to number and of urine was filtered through a nylon
riative were described elsewhere."!·' j gender restrictions in each age group
filter (pore size 12 urn, Millipore, United
The control srrategy adopted by the in each school, the actual age range
Kingdom) and the number of eggs
Ministry of Health was modified from was expanded to 6-14 years. \\7here counted under a microscope, for speci-
the WHO guidelines and involved the total number was not met. in one mens of less than [0 ml, the volumes
treatment once every two years to all school, rhe closest. school with the same
school-age children (5-15 were measured before filtration and theyears old).",j ecological conditions was selected. As a number of eggs per IO ml calculated.
Synergistic treatment for S'TH was a 1.50 result, a cohon of 1727 schoolchildren III tensity of S. haematobium infection
given to those who received treatment was randomly selected at baseline from was expressed as number of eggs per
for schisrosorni.asis. "the first neat .. 16 schools. The cohort children were 10 rnl of urine (e/IO rnl).
meru with PZQ and albendazole was exami.ned J[ baseline and followed
implemented during 2004 and 2005 up 1 year p osr-rreatrne nt (in 2(05) Stool examination
in a staggered two-phased campaign, and 2 years posc-Lreaunenr (in 20(6),
Due to the low scbool enrolment rare At each follow ..up, additional seven- ;\ single srool sample was collected from
in Burkina Faso, treatmenr was carried vear-old IirSl:..yc.ar new stuclcJl(s (ap- each child, Duplicate Kato·-Karz stides
out both through schools and com- proximately 10 boys and IO girls) from were prepared from each sample and
munities targeting school-age children each senrine'! school were randomly examined on the S,lme day to determine
not attending school. As described ,eJecred and exarnined. -nlcse children. S. I'lltmsuni infections. Eggs were counted
previously, \l the treatment campaign were expeered to havj~ been cargeccd and individual intensity oFinfecrion was
was coordinated and supervised by for rrcaullcnl through thecornmunity- expressed as eggs per gram of faeces (epg)
the Ministry of Health staff, involving based drug delivery before they joined caicuJated as tbe arithmetic mean of
education authorities and iocal. com- the schools, Infection starus ill these tbe two individual slide counrs, DtlC to
munities, A spcci.fic nalional 'rreanllent children sbould represent the quality logistical reasons, at the baseline .lurvey,
week' was designated in October each of community-based treatment. only aronnd half of cohort children were
year and health personnel at each level In additi.on the cohort follow-up, randomly sdecred and examined by theto
(regional, districr and dispensary) were a cross-sectional survey was conducted Karo---Katz method.
mobiJized, Drug delivery in schools was during the second Jdlow-up (2 years
carried out by trained school [eachers. post ..trcaunem), in which a group of
To reach non-enrolled children, health children (7-14 years old) outside the Of 1727 schookhildren recruited at
workers and community drug distribu- original cohort were randomly selected baseline, 76;) were' successfully traced.
mrs formed fixed uni!..1 ar. dispens;lry and examin~d i.n rhe sentinel schooLs. and re-examined ,It both follow-ups
and mobile units that visited villages '1he number, age and sex strllcrures were wi[b t.hree compler.e SCtS oflongirudinal
or hamlets seeking schoel-age chil- rnarcbed to [hose in the cohon who parasitological data on S. haemlltobium,
dre.n not attending school. Treatmem were present at the second follow-up Children who dropped oue or missed
against scbisrosom.iasis was de.livered in each school. infeCTion status in these ei ther of two fo 110\\ -up surveys were not
using the WHO dose pole ,nethod children she,ukl represent rhe yualiry of incJuded in the longimdinal analysis,
for PZQ. (600 mg [ablers), \5 A single treatment in children oU"side cohorts Base1i.ne characteristics of children suc-
dose of albendazolc (400 mg) was lIsed in schools, to confirm and validate tbe cessfullybllowed-up showed that tbey
against STH. cohort data, i.,e, no preferred n:eat:menr had a lower mean age (9,6 years versus
was given 10 cohort children, 11.0 years; P < 0.(1), a lower propor-
Parasitic infection status of each tion of boys (54,1 q{1 versus 59, 1%;
]1)(: monitoring survey was carried child was derermined by parasitological P < 0,(5); higher S. haematobium
OLlt among enrolled schoolchildren in eX<l.nl1.natiol1s. C:rosschecki,ng ,vas car- prevalence (59.9O,'IJ versus 53.1%: P<
selected schools due to logistic re;lsons, ried our ((:)1: quality control. Monir.or, 0,0l) bue a s.imji.ar intensity of S. har-
For the longi[lldinal surveys, sample ing acr.ivir.ks received ethical clearance matobium infection (93,3 ell 0 Ill] versus
size calculation and coho[[ design have hom the National Hea.lcb System Local 91.2 eliO ml: P> (J,()S), compared with
Bulletin at til(l World Healtri OrlJanizalionOctotJer 2008, 86 (10) 781
University of Ghana  http://ugspace.ug.edu.gh
Iable 1, Schistosoma haematabium prevalence and intensity of infection in the longitudinal cohort children before and after
treatment"
Variable Baseline 1 year 2 years Overall
(95%CI) post-treatment post-treatment reduction in %
(95%CI) (95%CI)
Prevalence in %
Overall prevalence (n= 763) 59,6 (56;2631) 6,2 (45-79) tt (5,S--9,6) 87.1
By region
Boucle du MoullOun (n= 236) 4[\.3 (42.lHi4,1) 8.4 (4,9-11.9) 12.,2.(80-16.3) 74.7
Nord (noe 259) 53.! (47,6-59./) 0,8 (00-1,8) 2.3 (05-4,1) 95.7
Sahel (n =199) 89.4 (85293,7) 12,1 (7.516,6) 11,6 (7.1-16,0) 87.0
Sud Ouest (fJ= 67) 34,3 (23,(H5J) 1.5 (0,0-4.4) 1.5 (0,0-4.4) 95.6
By sex
Boys (fJ= 403) 64,3 (59.fH38,9) rt (5.1-10,3) 11.4 (83-14.5)" 82.3
Girls (n= 3(0) 54.4 (49,3-59,6) 4,4 (?3-66) 36 (I,Hi,6) 93.4
-------- ---------------_._---_ .._-------_. __ ._------_._-------._-- -------
Intensity of infection in e/10 ml
Overall mean (n= 763) 94.2 (76Al11.9) 10 (0.2-1.9) 6.8 (U3-12 0)" 92.8
By region
Boucle du Mouhoun (n= 238) 76A (52.9-100.0) OJ (0.2-13) 19.2 (27-356)' 74.9
Nord (0'= 259) 63.4 0.0 (0.0-0.1) 0,8 (0.0-1.7) 987
Sahel (n= 199) 167.7 (117.9-?17A) 3.D (0.0-6.1) 2.0 (0.5-35) 98.8
Sud Ouest (0= 6/) 571 (115-103.9) 0.1 (0.0-0.1) 0.1 (0.0-0.3) 99.8
By sex
Boys (11= 403) 115,9 (91.0--140.8) 1.6 (0.1-320) 12,1 (2.4-21,8)' S9.6
Girls (11= 360) G9.9 (44.HJ5.1) 0.3 (0.1-06) 0.8 (0.0-17) 98.9
Ci, confidence interval; e/IO ml, number of egos ner W ITII urine.
" fill data atl or 2 years post-ueatment were significantly lower than at baseline (all p" 0,01)
" P < 0,05, significantly higher when cornparedwiml year post-treannent.
those who had dropped out. Among Results (;" 50 ell 0 ml) accounted for over 25%
763 children, 322 had valid data entry of the schoolchildren examined (Fig. 1).
illf S mansoni at all three surveys, 'These This decreased [0 just OA'X, at I year
longitudinal data, together with cross- Longitudinal cohort data posl·-neannenr and remained below 2%
sectional analysis of three sets of data Table 1 summarizes the parasitologi- at. 2 years post-treatment.
from the 7-year-'old children and two cal results from 763 cohort children
sets of data from the 7-14-year-olds, successfully examined at baseline, Cross-sectional data
are presented in this paper. Baseline 1 year post- trearrnenr and 2 years 'nlCSC data were compared with those
data from. the original cohort, includ- post-treatment. One round of mass of baseline children with the same ages
ing those who dropped out during the PZQ rrcatmcn r significantly [educed (7--14 years old) in the original cohort
follow-ups, served as the baseline data prevalence in the cohort children from before treatment. Two years after treat-
in the two cross-sectional analyses. 59,6~'() at baseline to 6,2% at 1 year ment, overall prevalence and intensity
Result tables together with 95% con- post"treatment and, importantly, re- of S, hnematobium infection were sig-
fidence intervals (Cl) were obtained mained at 7.7'Yi,2 years post-,trearment, nificantly lower than those ar baseline
using software S.i\.5 version 9.1 (SAS an overall 87, .1% reduction over 2 years by 77A'),u and 80.3% respectively (P <
Institute, Cary, NC, United States of (P < OJ)])_ The overall intensity ofin- (l.OI), Signiticanr reduction in both
America), Arirhrneric mean intensity of fenlon was signiflcandy reduced from prevalence and intensity of infection
infections was used in the analysis. '7,18 94.2 eil 0 rnl at baseline to only 1.0 was shown in all four regions and in
For longitudinal cohort data the differ- e/IO ml at 1 year post-treatment and borh boys and girls (I' < 0.01; Tabie 2).
ences were tested using the lvIcNernar's 6.8 c/l0 rnl at 2 years POS(-·tl'catrnent, As in rhe cohort data, the proportion of
test lor prevalence and the \Vi!coxon an overall reduci iun of 92,S'};' over heavy infecrlons was reduced from 25%
signed rank-sum test for mean intensi- 2 years (1' < 0.0 l ). SigniJicant reduc- to just 3.2% (Fig. 2). However, these
ties, For cross-sectional analysis the X2 tion in botl: prevalence and intensity of children outside the cohort did show a
test was used to compare difFerences infection was found in all four regions sli.ghtly higber prevalence and intensity
in prevalence and the Kruskal-Wallis and in both boys and girls (P < 0.01; of S hacmatobium infection than those
test [0 compare difTerences in mean Tabie 1), Irnportanrly, before treatment in the cohort as in 'TabIe 1 (1' < 0.(1) at
in[cnsities. the proporcion of heavy infections 2 ·years po.sr-rrearrnent.
782 Eluiietlil 01 tl18 Worlci HealU: Or[J8!I!Zation OCiob812008, 86 (10)
University of Ghana  http://ugspace.ug.edu.gh
Comparison of 3-year data from the
7-year-old scnootcnitdren Fig. I Changes in the category of intensity of Schistosoma haematabium infection inschoolchildren (n= 763); 3-year longitudinal data
Only S. haem atobium infection is pre-
sented here, as the infection level for rBJBas-eiin8
other helminths was low. /\5 in 'Elble 3 GJ One Y8:lr post- 1[831m8"t
(available at: http://www.who.in[/ [J Two yeers post-ireatmeot
bulletin/volumes/Sci/J ()/07 .()tiS694/ lI 95% confidence interval"~" "''_''_''H''_''_''_''_'' _
en/index.hrml), similar to the cohort
data, 1 year aftcr nearm cn r overall
both prevalence and intensity of S. hae-
matobium infection in rhe 7 -year-old
children showed a dramatic reduction,
by an average of 82.9% and 92.:YYo
respectively (1'< 0.(1). 1here was a
significalH uptrend in both overall
prevalence and intensity of infection
2 years post-treatment compared with
1-49 ~ 50
1 year post-treatment (P < 0.01), but
the overall level of prevalence and Intensity of infection (e/10 mil
intensity of infection was still far ell 0 rnl. of eggs per 10 rnl urine.
below the original level by 65.90;() and
78.4~'o respectively (P < 0.01). More
importantly, the proportion of heavy ducecl to 1.5~,oand 2.9 epg respectively
infections (2! 50 ell 0 ml) remained Longitudinal cotton data (P< o.o».
lower at 2.5% 2 years later compared Parasitological results on S. manson!
with 14% before treatment (Fig. 3). Cross-sectional datainfection in the longitudinal cohort
lIlt [rend in difFerent regions and in children successfully examined at base- In the cross-sectional data, S. mansoni
both genders was generally similar with line and followed ..up one year and two infection was also shown only in the
prevalence and intensity of infection years post-treatment are summarized in Sud Ouest region. In baseline children
post-t.rcatmcnt being signi.ficantly lower Tabl« 4 (available at: http://www.who. (7-14 years old) in the original cohort in
than at. baseline (P < 0.01) except in rhe int/bulletin/volumes/86i 10107-01.\86941 this region. prevalence of S. mansoni in-
south-west (Sud Ouest) region. There, cn/in dex.h unl). S. mansoni infection recti on was H:.2% (95°/h CI: 10.817.6;
the boys showed a significant increase in was detected only in rhe Sud Ouest re- n ~ 40S) and intensity of infection was
both prevalence and intensity of inlec .. gion in sentinel schools with prevalence 2:30 epg (95% CI: 11.8--34.2; n=
lion 2 years post-·treannertt compared of 13.60/<) and inrensiry of infection of 408) before treatment, Two years after
to one year post-trearment, while girls 22.4 epg .i n rhe region. 'Iwo yean after treatment, S. rnansoni prevalence in this
did nor. rrearmcnt these were signi.f.icantly rc- region was 7.6% (95'Jh CI: 4.4-11.0;
!7 -x: 248) and intensity of infection was
Fig.2 Changes in the category of intensity of Scilistosoma ttsemetontum infection 16.5 epg (95% CI: 1.931.0; n = 248)
in schoolchildren; cross-sectional data 2 years post-treatment (II::: 761) (both P -: 0.051.
compared with baseline data (n::: 1644)
100 Discussion
90 In line with previous findings,'? S. hae-
rnatobium infection was found preva-
lent throughout cohort schools in
the country with very high levels of
infection in the north, particularly in
the Sahel region where infection was
nearly universal in some schools (de-
tails not shown), and a moderate level
of infection in the Sud Ouest region.
Although S. haematobium infection was
relatively low in [he Sud Ouest com-
pared with other regions, S. rnansoni
infection was also found co be prevalent.
Intensity of infection (e/l0 011) Therctorc, th<: combined prevalence of
schistosomiasis was acruaHy vety high,
reaching nearly 50c),o in the longitudinal
data and more than 30% ill the cross-
ell [] mi. nurnber of egg:; per '1[] Ill! urine: N/I\. not avaiiarJi8.
sectional data at baseline. TIle baseline
BulIH!n ot tile World Healtrl Or[Janization iJctoljer 2008, 86 (10) 783
University of Ghana  http://ugspace.ug.edu.gh
data confirmed the significant: burden Table 2. Cross-sectional analysis of Schistosoma haematobium infection in the
caused by schistosoruiasis to school-age 7-14-year-old schoolchildren before and after treatment
children in Burkina. l-aso. \1(/eabo found
universally low S'rH infections (data Variable Baseline 2 years Overall
not shown).l1,is may be due ro the ['lct (95%CI) post-treatment reduction
that the national control programme on (95%CI) in%
lymphatic filariasis using albcndazolc Prevalence in %
and iverrnectin starred in 2001, and Overall prevalence 5~i.8 (534-:i8.2) 12.6 (102-15.0) llA
several rounds of treatment had. already (17= 1644) (17= 761)
been implemented in some areas of rhe
country.P:" By region
Boucle du Mouholill 58.6 (53.8-63.3) Ei.8 (117-20.0) 130
(n =413) (n = 291)
Nord 61.2 (56.5-65.8) 2.0 (0.0-4.8) 96.7
A single rrearrnenr significantly reduced (n=417) (n= 99)
S. baematobium infection in the country Sahel 84.2 (807-817) 30.0 (21.8-38.2) 644
and kept it low for the following 2 years. (17=412) (n= 120)
Two years after treatment, prevalence
S. Suci Ouest 184 (14.6-222) 4.5 (1.9-7.1) 75.5of haematohium infection in school- (17=402) (n~ 24:i)
age children was srill at. a significantly
lower level than at baseline and, more By sex
importantly. intensity of infection Boys 598 (56.7-63.0) 16.5 (12.9-20.1) 72.4
(17=936) (17= 4(6)
remained at a low level, 111e propor-
tion of heavy infections was greatly C,irls 50.6 (46.9-54.2) 8.2 (5.3-11.0) 83.8
(17= 708) (11=,355)
reduced. This is particularly imporranr ----~---.---.----------~-----------------------------.-----_------_._------
as high intensity of S. hnemntobi um Intensity of infection in e/10 ml
infection has been shown to contribute Overall mean 91.3 (80.0-102.7) 18.0 (9.4-26.5) 80.3
to morbidity, including anaemia, in (1I.~1544) (11= 761)
children." 1]1e reduction in prevalence By region
and intensity ofinfecrion was confirmed Boucle au Mouhoun 106.7 (86.0-127.5) 37.4 (16.9-58.0) 64.9
by both longitudinal cohort follow-up (17=413) (17= 297)
and cross-sectional survey. In previous Nord 91.0 (67.3-114.6) 0.1 (0.0-0.2) 99.9
small-scale studies on S. haematobium (17=417) (17= 99)
control in eastern Africa. an annual Sahel 126.9 (99.3-154.4) 14.5 (00-31.2) 88.6
treatment sr.rateg), was predominantly (n= 412) (11= 120)
used, with varying results.ll." However, Sud Ouest ~l9.4 (22.8-~i6.1) 3.4 (00-/.3) 914
in western Africa, one study in the Niger (/J= 402) In = 24~))
showed that, j years after a single PZQ By sex
treatment, prevalence and intensity of Boys 111.8 (95.6-128.1) 26.8 (12.3-41.3) 76.0S. lutematohium infection remained sig- (n= 936) (11= 406)
nificanrly lower than at baseline.">" In
64.2 (49.1-79.3) 7.9 (0.0-15.8) 877
another study in Ghana, with one si.ngle Girls
(n= 708) (11~ 355)
I'ZQ treatment, intensity of S. haemato-
bium infection was reduced by 8099% CI. conndence interval; 8/1 C mi. nurnhe. of G(JQsper 1() rnl urne: n. sample size in tile gmup.
12 months after treatment and remained
very low in two of three study areas 24
months afrer treatment." Our results dry year and rrearrnenr was delivered in continued cfforr in monitoring disease
are in line with these studies, suggesting the dry season. These rwo important transmission and of repeated treatment
that a more spaced. trcatmenr srrategy, :15 factors together may have helped to when and where necessary.
implemented in Burkina Faso, is highly red uce transmission '6 and, therefore, Throughout the 2 years, the drop-
effective on S. harmatobiurn infections, should be considered when implement- our. rate of cohort children was high,
even in highly-endemic areas. In ad- ing a national control programme in parricularly in the Sud Ouest region
dition, we abo observed a significant other sub-Saharan countries 1'.0 maxi- where very few original cohort: children
reduction in S. mansoni infection during mize the treatment impact. Neverrhe- were [raced and re-examined at both
the 2 years after ueatmcnt. less, the general uptrend of the preva- follow-ups. One of rhe main reasons for
One of t.he facto rs likely to have lence and imensi ly of S_ haerncliobium rhe lo.s~ of cohort children wa_s hrnily
contributed to the great impact dem- infection shown 2 years post'-treatmellt, migrarion, which is very common in the
onstrared in Burkina Faso is the high compared wilb 1 year pOSI"rreatment, country and particularly in this region
nationwide treaUl1en t coverage (over could also signal. a porenrial rebound (SeyJou '[(lUre, personal observation).
90%) achieved in a relatively ShOll space of S. htlCrnf/tobium infection should Another of the main reasons was that a
of time by [he control programme. II drug; distr.iill.ltion be interrupted. -lhis propornon of the original cohort (older
Anorher factor is that 2004 was a very therefore high liglHs [he importance of age groups) had n:Hllrdlly progressed to
784 [Melin ot tile World Heal!!; Or[Janizaliorr Octol)er2008, 86 (10)
University of Ghana  http://ugspace.ug.edu.gh
secondary schools over the srudy period.
High drop-out is indeed a relatively Fig 3. Changes in the category of intensity of Schistosoma haematobium infection in
the 7-year-old first-year schoolchildren before treatment (n=154), 1 year post-
common problem in the monimring treatment (n=30-1) and 2 years post-treatment (n=317)
activities of our programmes in sub-
Saharan Africa. 100 ![5ila~ci;;ie---------'-----
90- 10 One year post-treatment
"0
Q.) !0 Two Yearspost·tI'(~iltrn8n~
c: BO
Unlike in Uganda,":" a biennial treat- .§ Il_I... 95"~ confidence interval~
ment of school-age ch ildren (5- J 5 '>"< lO<1>
years old) through school-based and eC 60
community-based drug deliveries was :E 50
implcmcnrcd in Burkina Faso. This :E(.)
40··
decision was based on previous experi- '00
.t=
r)n
ence with S. hnemntobium in western (.) ~J\~
Africa2-1'S and on rhe fact chat the ''l:"i 20
ongoing monitoring and. evaluation ?f- lO-
activities showed a low level ofinlecrion
1 year post-trealfnen L! 4 Curren r resul ts, 0··
together with previous f1ndings by oth-
1 5 lntensity of infection (ell 0 ml)ers/ :: suggest that the \'\iTIO-recom-
mended treatment strategies on urinary ellO m!, number of eogs per 10 rnl urne.
schistosomiasis should be adopted with
some degree of Ocxibi!ity according t.o US$ 0 ..32.)) .A. possible further reduc- of PZQ with high coverage rates in
di.fferent epidemiological and geographi- [ion oftrearrnenr frequencv for urinary Burkina Paso. We demonstrated, for the
cal sertings. Provided that coverage is schistosomiasis, where applicable, is firxt time on a national scale, that such
high and is implemented in a dry season, expected [0 [urrher reduce the overall rreatment frequency can be successfully
treatment once every two years may costs of the control activities. The applied to control urinary schistoso-
be sufficient, even in highly-endemic current national control programme miasis in sub-Saharan Africa. This may
regions such as Sahel and Boucle du in Burkina Faso has recently entered provide a cost-dFectivc treatment strat-
Mouhoun, and in less endemic regions a new phase - integrated control of egy fClf similar national schistosomiasis
perhaps treatment every three or more neglected tropical diseasesY·J.s The control programmes in resource-limited
years could equally prove sufficient. Ir next rounds of treatment are planned settings.
is however more d ifficul t to make infer- to be delivered in an integrated man-
ences on the appropriate interval of treat- ncr to include schistosomiasis, STII, Acknowledgements
ment on intestinal schistosomiasis from lymphatic filariasis. onchocerciasis We thank all the stalf at the Programme
the current data because of rhe relatively and trachoma.' In this framework, the. National de Luue centre la Schistose-
small number of individuals with such best way to tackle schistosomiasis is miase er les Vers lntesrinaux, Minisrerc
infection enrolled in oursurvey, and the being assessed.1i:eatment with reduced de L, Sante, Burkina Faso, and Ruairidh
lower levels of infection registered. Our frequency plus integrated control Crawford for his data analysis during
study also suggests that monitoring and strategies rnay significanr.ly increase his student project.
evaluation is a cruci,ll component of the the sustainability of national control
national conrrol programme it)" finc- programmes in Burkina Faso and in Funding: lbe Schistosomiasis Control
tuning a treatment strategy according the rest of sub-Saharan Africa. Initiative is sponsored by the BiJi and
to national and local epidemiological Melinda Gates FOtllldarion, which had
conditions. Conclusion no role in smdy design, data collection
Previous analysis has shown [hac in and analysis, decision to publish, or
Burkina Faso, th~ lOtal COStS per child 'This study showed Ihat a significant preparation of the manuscript.
treated against sch.istosomiasis and impact on uri.nary schistosomiasis
STH, including drug and delivery, was '>vas achieved by biennial distri.burion Competing interests: None declared.
Resume
Impact it deux ans d'un traitement unique par Ie praziquantel sur I'infestation par des schistosomiale dans Ie
cadre du programme national de lutte contre la schistosomiase du Burkina Faso
Objectif Evaluer I'impact sur ia sdlistosorniase du traiternelll biennal illiervalies d'un an. a Iravers une enquete longitudinale. D'autres
c~ntre 18SCilistosomiase par Ie praziquantel (PZCJ)chez ies 8nfants groupes d'ecoliers ant ete suivis dans Ie cadre d'enquetes
d'age scolalre du Burkina r:aso, premier pays avant obtenu une transversales. Des examens parasitologiques, visant a mettre en
couverture nationale totale par ce traiternelll de plus de 90 % de evidence Schistosoma haernatobium et SChistosoma mansoni, ont
la population d'age scolaire. ete pratiqu8s. La prevalence et l'lntellsite de I'infestation avant et
Methodes Une cotlorte de 1727 eco!iers (6-14 ans) a ete SUiVI8 a apres Ie lraitement ont egalernent ete analysees.
Bullulin of tile World Hoal!!) Or!)anizalion October 2008,86 (10) 785
University of Ghana  http://ugspace.ug.edu.gh
IResearch
> SL<''''L''''.n
Resultats Les donnees collectees pour la cohorte lonqitudinale Ie biais des systernes de delivrance communautaires, ont rnis en
monirent qu'une tournee unique de traitement par Ie r)ZQ a penn is evidence une diminution a la lois de la prevalence (65,9 %) et de
de reduire la .prevalence de l'inteslation par S. haernalobium l'intensite (/8,4 %) de l'inlestation par S. flaematobiurn deux ans
de 87°/" (baisse considerable de 59,6 % a 7,7 %) et t'intensite apres Ie lraiternent unique. Ces cornparaisons relevaient aussi une
de cene infestation de 92,8 % (baisse de 94,2 a 6,8 ceufs!1 0 ml balsse consequente de I'infestation par S. mansoni.
d'urine) deux ans apres Ie traitement. Cet effet sur I'intestation a Conclusion Une diminution rnportanta et durable de I'infestation
ote contrme par une encuete transversale realises 2 ans 811alernenl par' S. flaematobium a et6 obtenue par un traitement biennal des
apres Ie traiternent. ~)oint important : la proportion d'ernants d'age enfants (1'[lge scolaire au Burkina Faso Cette demarche pourrait
scolaire lourdement infestes par S. haemalobiurn est tornbee cie constituer una strategie de traiternent d'un bon rapport coUt!
pres de 25 % avant Ie traltement a environ 2-3 % deux ails apres efticacite pour d'autres programmes nationaux analogues de lutte
celui-ci. Des comparaisons transversales chez Iss enfants de 7 ans centre la scllistosomiase en Afrique sub-saharienne.
en premiere ann6e d'6cole primaire, ayanl re~u Ie tra;tement par
Resumen
Impacto en la esquistosomiasis al cabo de dos alios de un solo tratamiento con prazicuantel en el programa
nacional contra esa infeccion en Burkina Faso
Objetivo Evaluar el irnpacto en la esquistosorniasis a ios cios ai'ios infeccion sa via confirmado tam bien par una encuesta transversal
del lratarnlento bienal COil prazicuantel (PZO) en una polJlacic)n eie realizacla a los 2 aiios del tratalTliento. Un dato importallte es que la
ninos en edad oscolar en Burkina Faso, el primer pais que logr6 la prop ore ion (je ninos en edarJ escolar con infecei6n seria disminuyo
plena cobertura nacional tratando a mas del 90% de la poblacion de aproxirnadamente un 25% antes del tratamiento a un 2%-3%
en edad escolar. a los 2 all0s del misnlo. La eomparacion transversal del estado de
Metodos Se realiz6 un estudio longitudinal para seguir la infeccion POI'S. flaematobiurn entl-e l1il10S de 7 alios en Sli primer
evolucion de una cotlOrte de 1'12'1 escolares (6-14 atlos) a anD de escolariciad, que recibieron tratamiento gracias a un sistema
intervalos de un anD. Se sorneti(j tarnbien a seguimiento a olms de surninistro de rnedicarnentos basado en la comunidad, tarnbien
grupos de escolares mediante encuestas transversales. Se puso de relieve una reduceion importante tanto de la prevaiel1cia
realizaron examenes parasitol6gicos para detectar la presellcia (65,9%) corno de la intensidaej (78,4%) de la infecci6n por
de Schistosoma flaematobium y SciJistosoma mansoni, S. /7aema/obiuf77 dos anos ciespu8s del tratarniento [Inico. Tambien
determinandose la prevalellcia e intens!dad de la infecc;on antes y S8 iogro reducir de forrna notable ia infeccion por S. mansoni.
despues del tratamiento. Conclusion EI tratamiento bienal de los ninos en edad escoiar en
Resultados Los datos de la cohorte iongitudinal rrluestrall quo, Burkina Faso logro reducir considerablernsnte y de forrna sostenida
transcurricJos dos ahos, Llna soia ronda de tratarnionto COil PZQ ia infeccion par S. tiaernatobium. Esto brindaria lIna estrategia de
tlabia reducirJo consirjerablernente la prevalencl3un 87% (cie tralarniento costoeficaz para otms pr-ogmrnas nacionales sirnilares
59,6% a '1,7%)" e intensidarj·92,8% (de 94,2 a 6,8 huevos/10 de control eje la esquistosorniasis 011 el Africa subsahariana.
ml de orina)- ele la infeccloll por S. ilaematobium EI impacto en la
~
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786 lMelin 01 theWorld Healtll Orpanilal;on Oclober 2008, 86 (10)
University of Ghana  http://ugspace.ug.edu.gh
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Table 3. Cross-sectional analysis of scmstosoms haematobium infection in the 7-year-old first-year schoolchildren before and after
treatment'
Variable Baseline 1 year post-treatment 2 years post-treatment Overall
(95%CI) (95% CI) (95% GI) reduction in %
Prevalence in %
Overall prevalence 41.6 (33.8-49.3) 7.1 (4.3-10.1) 14.2 (10.4-18,0) 65.9
(n.", 154) (IJ= 307) (n= 317)'
By region
Boucle du Mouhoun es.s (23.4-47.8) o (N/A) 6.7 (0.4-13.0) 81.2
(17= 59) (n= 20) (17= 60)
Nord 51 A (35.3-675) 4.0 (ll2-79) 2.0 (0.0-4.8) 96.1
(n= 3/) (n= 99) (17= 98)
Sahel 92.0 (fJ1.4-1 OO.Oj 16/ (9.6-23./) 30.0 (21.8-38.2) 674
(n= 25) (n= lOB) (n= 120)'
Sud Ouest o (WA) o (NiA) 711/1.0-16.1)
(n= :)3) (n= 80) (17 = 39)
By sex
Boys 39.8 (29.2-50.3) 6,0 (2.2-9.8) 184 (12,5-24.41 53.8
(n= 83) (n= 150) (n= 163)'
Girls 43./ (32,1-55.2) 8.3 (4.0-12,6) 9.7 (5.1-14.4) 77.8
(n= 71) (11= 157) (nocc 154)
Intensity of infection in e/10 ml
Overall mean 63.5 (30,0-970) . 4.9 (0.0-11 A) 13.7 (2.5-·24.8) 78.4
(17= 154) (n=307) (n ~.C 317)'
By region
Boucle du Mouhoun 63.7 (22,2-1 0~j.3) o (N/A) 33.6 (0.0-80.3) 47.3
(n= 59) (n = 20) (11= 6C)
NorcJ 44,0 (0,0-100.5) 1.1 (0.0-2.1) 01 (0.0-0.2) 99.8
(n= 37) (17= 99) (n = 98)
Sahel 17~).6 (109-34(),2) 13.0 (00-31.5) 14.5 (0.0-31.3) 91,7
(n= 25) (17= 1(8) (IJ = 120)°
Sud Ouest (l(N/A) o (NiA) 14.5 ((lO-38.~i)
(n= 33) (n = 80) (n= 39)
By sex
Boys 91.2 (33.4--148,9) 1() (0.0--2.1) 24.9 (3.3-46,6) 72.7
(11= 83) (n 00 150) (n = 163)':
Girls 31.2 (4.1-58,2) 8.7 (0.0-21.4) 1.7 (05--30) 94.6
(n= 71) ({/= 157) (n z: -154)
;:;1,confidence interval; ell () rnl. number of [:gg, per 1(J rnl urine: ~il4,not available, n, sarrp.o size i'll!1o group.
H Except in Suci Ouest, all data at 1 year or 2 years post-treatment were significantly lower man at baseline (all P < 0.01).
" P <: !l.(J;i significantly high,·" when conmarr:ri with 1 year post-treatment.
Table 4, Schistosoma malison; prevalence and intensity of infection in the longitudinal cohort children before and after treatment'
Variable Baseline 1 year post-treatment 2 years post-treatment
(95%CI) (95%CI) (95% Cil
Prevalence in %
Overaii (11= 322) 2.8 (10-46) 1.6 (0.2-2.9) 0.3 (0.0--0 9)
Sud Ouest (17= 66) 13(3 (54-21.9) 7,6 (L!-14.0) 1.5 (0,0-4.5)
Intensity of infection in epg
Overall (n = 322) 4[i (0.0-9/) 7.0 (0.0-15.1) O.G (0.0-18)
Sud Ouesl (n~ 66) 22.4 (0.047.3) 33.8 (0.0·-13.7) 2.9 (0.O·-S,7)
Cl, comldence mterval. ep~J, nurnher of egGs per uram of faeces .
.1 All data at 2 yean; post-treatment ~venl siQnitica~ltly lower than (It baseline (all P < D.l)!)). No significant diHefenG) was found netween 1 year post-treatment and
baseline or bctN8el'l? years 3i1lj 1 year pest-treatment (I'> D.Ob).
Bulletin of tile Warici Healtrl OroarlizaliOn Oct()tJW 2008, 86 (10) A