Research Articles

Permanent URI for this communityhttp://197.255.125.131:4000/handle/123456789/22010

A research article reports the results of original research, assesses its contribution to the body of knowledge in a given area, and is published in a peer-reviewed scholarly journal. The faculty publications through published and on-going articles/researches are captured in this community

Browse

Search Results

Now showing 1 - 10 of 20
  • Thumbnail Image
    Item
    In vitro antiplasmodial activity, LC-MS analysis, and molecular docking studies of bioactive compounds from Tetrapleura tetraptera (Fabaceae) fruits
    (Scientific African, 2023) Hamidu, S.; Adams, L.; Oduro, P.K.; et al.
    Malaria continues to be a major public health concern, particularly for children and pregnant women in areas where the disease is endemic. Developing safe and efficient antimalarial therapies to fight the disease is essential. Medicinal plants represent a potential source for the development of new antimalarial drugs. Tetrapleura tetraptera is a plant native to West Africa and traditionally used to treat several diseases including Malaria. Here, we investigated the antiplasmodial ac tivities of T. tetraptera fruit extracts against the chloroquine-sensitive (Pf3D7) and chloroquine resistant (PfDD2) strains of Plasmodium falciparum in vitro using SYBR green assay. In addition, the antioxidant potential of the fruit extracts was also determined. LC-MS analysis was carried out to identify the bioactive compounds in the extracts. Molecular docking studies provide significant prima facie evidence of inhibition hence, to evaluate the potential inhibition of Plasmodium fal ciparum dihydroorotate dehydrogenase (PfDHODH), a validated malaria drug target, the identi fied compounds were docked against PfDHODH. Strong antiplasmodial activities were demonstrated by the ethyl acetate and ethanolic extracts of T. tetraptera fruit, with IC50 values of 16.12 ± 0.04 µg/mL and 2.06 ± 0.02 µg/mL against the Pf3D7 strain, respectively. In the DPPH radical scavenging experiment, the ethanolic extract revealed considerable antioxidant activity with an EC50 value of 0.21 ± 0.82 mg/mL. Seven bioactive compounds were identified in the extract using LC-MS analysis. N-Methyl-1H-indole-3-propanamide (I), Tazolol (II), and Isopentyl salicylate (III) were identified as potential inhibitors of PfDHODH with high binding affinities ranging from -32.08 to -30.69 kcal/mol. The potential lead compounds also interacted with Gly181, Leu531, and Arg265, which are critical amino acid residues in the catalytic activity of PfDHODH. These findings support the traditional use of T. tetraptera fruit extracts for the treat ment of malaria and as promising avenues for antimalarial drug development.
  • Thumbnail Image
    Item
    Malaria vaccine-related adverse events among children under 5 in sub-Saharan Africa: systematic review and meta analysis protocol
    (BMJ Open, 2023) Ohene-Adjei, K.; Manu, A.A.; Danso-Appiah, A.; et al.
    Introduction The RTS,S vaccine has been approved for use in children under 5 living in moderate to high malaria transmission areas. However, clinically important adverse events have been reported in countries in sub Saharan Africa. This systematic review aims to assess the frequency, severity and clinical importance of vaccine related adverse events. Methods and analysis This systematic review protocol has been prepared following robust methods and reported in line with the Preferred Reporting Items for Systematic reviews and Meta-Analyses for protocols guidelines. We will search PubMed, CINAHL, LILACS, Google Scholar, SCOPUS, WEB OF SCIENCE, Cochrane library, HINARI, African Journals Online, Trip Pro and TOXNET from 2000 to 30 September 2023, without language restrictions. We will also search conference proceedings, dissertations, World Bank Open Knowledge Repository, and WHO, PATH, UNICEF, Food and Drugs Authorities and European Medicines Agency databases, preprint repositories and reference lists of relevant studies for additional studies. Experts in the field will be contacted for unpublished or published studies missed by our searches. At least two reviewers will independently select studies and extract data using pretested tools and assess risk of bias in the included studies using the Cochrane risk of bias tool. Any disagreements will be resolved through discussion between the reviewers. Heterogeneity will be explored graphically, and statistically using the I2 statistic. We will conduct random-effects meta-analysis when heterogeneity is appreciable, and express dichotomous outcomes (serious adverse events, cerebral malaria and febrile convulsion) as risk ratio (RR) with their 95% CI. We will perform subgroup analysis to assess the impact of heterogeneity and sensitivity analyses to test the robustness of the effect estimates. The overall level of evidence will be assessed using Grading of Recommendations Assessment, Development and Evaluation. Ethics and dissemination Ethical approval is not required for a systematic review. The findings of this study will be disseminated through stakeholder forums, conferences and peer-review publications.
  • Thumbnail Image
    Item
    Malaria, Urogenital Schistosomiasis, and Anaemia in Pregnant Ghanaian Women
    (Hindawi Journal of Parasitology Research, 2023) Frempong, N.A.; Ahiabor, C.; Anyan, W.K.; et al.
    Anaemia is common in sub-Saharan Africa, and parasitic infections could worsen its burden during pregnancy. Moreover, women become susceptible to malaria during pregnancy. We investigated Plasmodium falciparum (P. falciparum) and Schistosoma haematobium (S. haematobium) infections and determined their association with anaemia during pregnancy. Methods. A cross-sectional study involving 707 pregnant women attending antenatal care visits (ANC) and 446 at delivery was conducted in Battor and Adidome hospitals. Pregnant women were screened by microscopy and qPCR for P. falciparum and S. haematobium infections. Haemoglobin (Hb) levels were determined, and most participants received intermittent preventive treatment during pregnancy (IPTp) during ANC till delivery. Regression analyses were performed for associations between parasite infection and anaemia. Results. P. falciparum microscopy prevalence at ANC and delivery was 8% and 2%, respectively, and by PCR 24% at ANC and 12% at delivery. Anaemia prevalence at ANC was 52% and 49% at delivery. There was an increased risk of anaemia with P. falciparum infection (aOR = 1 92; p = 0 04). IPTp (p = 0 003) and age (p = 0 004) were associated with increased Hb levels at delivery. S. haematobium prevalence by microscopy was 4% at ANC and 2% at delivery. No significant correlation between S. haematobium and Hb levels was observed (coef = − 0 62 g/dl; p = 0 07). Conclusion. High anaemia prevalence was observed during pregnancy, and P. falciparum infection was associated with anaemia at ANC. Low S. haematobium prevalence could be attributed to previous praziquantel treatment during mass drug administration. Routine diagnosis and treatment of S. haematobium infections in endemic areas could be initiated to reduce schistosomiasis during pregnancy.
  • Thumbnail Image
    Item
    Co-infection of Plasmodium falciparum and Schistosoma mansoni is associated with anaemia
    (Malaria Journal, 2023) Dassah, S.D.; Nyaah, K.E.; Amenga‑Etego, L.; et al.
    Background Malaria and schistosomiasis persist as major public health challenge in sub-Saharan Africa. These infections have independently and also in polyparasitic infection been implicated in anaemia and nutritional defcien‑ cies. This study aimed at assessing asymptomatic malaria, intestinal Schistosoma infections and the risk of anaemia among school children in the Tono irrigation area in the Kassena Nankana East Municipal (KNEM) in the Upper East Region of Northern Ghana. Methods A cross sectional survey of 326 school children was conducted in the KNEM. Kato Katz technique was used to detect Schistosoma eggs in stool. Finger-prick capillary blood sample was used for the estimation of haemoglobin (Hb) concentration and blood smear for malaria parasite detection by microscopy. Results The average age and Hb concentration were 10.9 years (standard deviation, SD:±2.29) and 11.2 g/dl (SD:±1.39) respectively with 58.9% (n=192) being females. The overall prevalence of infection with any of the para‑ sites (single or coinfection) was 49.4% (n=161, 95% confdence interval, CI [44.0–54.8]). The prevalence of malaria parasite species or Schistosoma mansoni was 32.0% (n=104) and 25.2% (n=82), respectively with 7.7% (n=25) coin‑ fection. The prevalence of anaemia in the cohort was 40.5% (95%CI [35.3–45.9]), of which 44.4% harboured at least one of the parasites. The prevalence of anaemia in malaria parasite spp or S. mansoni mono-infections was 41.8% and 38.6%, respectively and 64.0% in coinfections. There was no statistically signifcant diference in the odds of being anaemic in mono-infection with malaria (OR=1.22, 95% CI 0.71–2.11, p=0.47) or S. mansoni (OR=1.07, 95% CI 0.58–1.99, p=0.83) compared to those with no infection. However, the odds of being anaemic and coinfected with malaria parasite species and S. mansoni was 3.03 times higher compared to those with no infection (OR=3.03, 95% CI 1.26–7.28, p=0.013). Conclusion The data show a high burden of malaria, S. mansoni infection and anaemia among school children in the irrigation communities. The risk of anaemia was exacerbated by coinfections with malaria parasite(s) and S. mansoni. Targeted integrated interventions are recommended in this focal area of KNEM.
  • Thumbnail Image
    Item
    The impact of anti-malarial markets on artemisinin resistance: perspectives from Burkina Faso
    (Malaria Journal, 2023) Guissou, R.M.; Amaratunga, C.; Tindana, P.; et al.
    Background Widespread artemisinin resistance in Africa could be catastrophic when drawing parallels with the failure of chloroquine in the 1970s and 1980s. This article explores the role of anti-malarial market characteristics in the emergence and spread of arteminisin resistance in African countries, drawing on perspectives from Burkina Faso. Methods Data were collected through in-depth interviews and focus group discussions. A representative sample of national policy makers, regulators, public and private sector wholesalers, retailers, clinicians, nurses, and commu nity members were purposively sampled. Additional information was also sought via review of policy publications and grey literature on anti-malarial policies and deployment practices in Burkina Faso. Results Thirty seven in-depth interviews and 6 focus group discussions were conducted. The study reveals that the current operational mode of anti-malarial drug markets in Burkina Faso promotes arteminisin resistance emergence and spread. The factors are mainly related to the artemisinin-based combination therapy (ACT) supply chain, to ACT quality, ACT prescription monitoring and to ACT access and misuse by patients. Conclusion Study fndings highlight the urgent requirement to reform current characteristics of the anti-malarial drug market in order to delay the emergence and spread of artemisinin resistance in Burkina Faso. Four recommenda tions for public policy emerged during data analysis: (1) Address the suboptimal prescription of anti-malarial drugs, (2) Apply laws that prohibit the sale of anti-malarials without prescription, (3) Restrict the availability of street drugs, (4) Sensitize the population on the value of compliance regarding correct acquisition and intake of anti-malarials. Funding systems for anti-malarial drugs in terms of availability and accessibility must also be stabilized.
  • Thumbnail Image
    Item
    RTS,S/AS01E vaccine defaults in Ghana: a qualitative exploration of the perspectives of defaulters and frontline health service providers
    (Malaria Journal, 2023) Okyere, J.; Bediako, V.B.; Nwameme, A.U.; et al.
    Background While Ghana has a good track record in the Expanded Programme on Immunization, there are sub stantial challenges with regards to subsequent vaccinations, particularly after the frst year of life of the child. Given that the last dose of the RTS, S/AS01E vaccine against malaria is administered at 24 months, there is a high likelihood of default. Hence, it is imperative to understand the dynamics and reasons for the defaults to enable the develop ment of efective implementation strategies. This study explored why caregivers default on the RTS, S/AS01E vaccine from the perspective of health service providers and caregivers. Methods This study employed an exploratory, descriptive approach. Using a purposive sampling technique, caregiv ers who defaulted and health service providers directly involved in the planning and delivery of the RTS, S/AS01E vaccine at the district level were recruited. A total of fve health service providers and 30 mothers (six per FGD) par ticipated in this study. Data analysis was done using NVivo-12 following Collaizi’s thematic framework for qualitative analysis. The study relies on the Standards for Reporting Qualitative Research. Results Reasons for defaulting included the overlap of timing of the last dose and the child starting school, dis respectful attitudes of some health service providers, concerns about adverse side efects and discomforts, travel out of the implementing district, the perception that the vaccines are too many, and lack of support from partners. Conclusion To reduce the occurrence of defaulting on the RTS, S/AS01E vaccine programme, stakeholders must reconsider the timing of the last dose of the vaccine. The schedule of the RTS, S/AS01E vaccine should be aligned with the established EPI schedule of Ghana. This will signifcantly limit the potential of defaults, particularly for the last dose. Also, the fndings from this study underscore a need to encourage male partner involvement in the RTS, S/AS01E vaccine programme. Health promotion programmes could be implemented to raise caregivers’ awareness of potential adverse reactions and discomforts—this is necessary to prepare the caregiver for the vaccine process psychologically.
  • Thumbnail Image
    Item
    Recent increase in low complexity polygenomic infections and sialic acid-independent invasion pathways in Plasmodium falciparum from Western Gambia
    (Parasites & Vectors, 2023) Nganyewo, N.N.; Awandare, G.A.; Bojang, F.; et al.
    Background The malaria parasite Plasmodium falciparum utilizes multiple alternative receptor-ligand interac‑ tions for the invasion of human erythrocytes. While some P. falciparum clones make use of sialic acid (SA) residues on the surface of the human glycophorin receptors to invade the erythrocyte, others use alternative receptors independent of sialic acid residues. We hypothesized that over the years, intensifed malaria control interventions and declining prevalence in The Gambia have resulted in a selection of parasites with a dominant invasion pathways and ligand expression profles. Methods Blood samples were collected from 65 malaria-infected participants with uncomplicated malaria across 3 years (2015, 2016, and 2021). Genetic diversity was determined by genotyping the merozoite surface protein 2 (msp2) polymorphic gene of P. falciparum. Erythrocyte invasion phenotypes were determined using neuraminidase, trypsin, and chymotrypsin enzymes, known to cleave diferent receptors from the surface of the erythrocyte. Schiz‑ ont-stage transcript levels were obtained for a panel of 6 P. falciparum invasion ligand genes (eba175, eba181, Rh2b, Rh4, Rh5, and clag2) using 48 successfully cultured isolates. Results Though the allelic heterozygosity of msp2 repeat region decreased as expected with reduced transmission, there was an increase in infections with more than a single msp2 allelotype from 2015 to 2021. The invasion pheno‑ types of these isolates were mostly SA independent with a continuous increase from 2015 to 2021. Isolates from 2021 were highly inhibited by chymotrypsin treatment compared to isolates from 2015 and 2016. Higher invasion inhibi‑ tion for 2021 isolates was further obtained following erythrocyte treatment with a combination of chymotrypsin and trypsin. The transcript levels of invasion ligand genes varied across years. However, levels of clag2, a rhoptry associated protein, were higher in 2015 and 2016 isolates than in 2021 isolates, while Rh5 levels were higher in 2021 compared to other years. Conclusions Overall, these fndings suggest increasing mixed infections with an increase in the use of sialic-acid independent invasion pathways by P. falciparum clinical isolates in the Western part of Gambia
  • Thumbnail Image
    Item
    Plasmodium falciparum infection and naturally acquired immunity to malaria antigens among Ghanaian children in northern Ghana
    (Parasite Epidemiology and Control, 2023) Seidu, Z.; Lamptey, H.; Whittle, N.O.; et al.
    Background: The surge in malaria cases and deaths in recent years, particularly in Africa, despite the widespread implementation of malaria-control measures could be due to inefficiencies in malaria control and prevention measures in malaria-endemic communities. In this context, this study provides the malaria situation report among children in three Municipalities in Northern Ghana, where Seasonal Malaria Chemotherapy (SMC) is implemented by Ghana Health Service (GHS). Methods: A cross-sectional household survey was carried out to assess the malaria knowledge, attitudes, and practices (KAP) and malaria prevalence in 394 households in 13 rural communities in the Kumbugu, Nanton and Tolon Municipalities, Northern Region, Ghana. This was followed by screening for P. falciparum infection with anti-HRP2 RDT and PCR among children 1–17 years in the households. Plasma levels of IgG specific for crude P. falciparum antigen (3D7) and four re combinant malaria antigens (CSP, GLURP, MSP3, and Pfs230) were assessed by ELISA. The malaria and parasitaemia data were converted into frequency and subgroup proportions and disaggregated by study sites and demographic information of the participants. The ELISA data was converted to arbitrary units (AU) and similarly compared across study sites and demographic information. Results: The P. falciparum infection rate and frequency of malaria were high in the study areas with significant age-dependent and inter-community differences, which were reflected by differences in plasma levels of P. falciparum-specific IgG. Over 60% of households reported the use of bed nets and indoor insecticide sprays/coils, and 14% mentioned bush clearing around homes (14%) as malaria preventive measures. Community health centres were the preferred place for households (88%) to seek malaria treatment but over-the-counter drug stores were the major source (66%) of their antimalarials. Overall, malaria preventive and treatment practices were sub-optimal. Conclusions: P. falciparum infection and malaria are still high in the studied communities, indi cating that preventive and control measures against the disease in the region remain inadequate. Efforts to ensure high SMC compliance and to improve preventative and treatment practices thus seem cost-beneficial “low-hanging fruits” in the fight against malaria in the Northern Region of Ghana.
  • Thumbnail Image
    Item
    Plasmodium falciparum infection and naturally acquired immunity to malaria antigens among Ghanaian children in northern Ghana
    (Parasite Epidemiology and Control, 2023) Seidu, Z.; Lamptey, H.; Whittle, N.O.; et al.
    Background: The surge in malaria cases and deaths in recent years, particularly in Africa, despite the widespread implementation of malaria-control measures could be due to inefficiencies in malaria control and prevention measures in malaria-endemic communities. In this context, this study provides the malaria situation report among children in three Municipalities in Northern Ghana, where Seasonal Malaria Chemotherapy (SMC) is implemented by Ghana Health Service (GHS). Methods: A cross-sectional household survey was carried out to assess the malaria knowledge, attitudes, and practices (KAP) and malaria prevalence in 394 households in 13 rural communities in the Kumbugu, Nanton and Tolon Municipalities, Northern Region, Ghana. This was followed by screening for P. falciparum infection with anti-HRP2 RDT and PCR among children 1–17 years in the households. Plasma levels of IgG specific for crude P. falciparum antigen (3D7) and four re combinant malaria antigens (CSP, GLURP, MSP3, and Pfs230) were assessed by ELISA. The malaria and parasitaemia data were converted into frequency and subgroup proportions and disaggregated by study sites and demographic information of the participants. The ELISA data was converted to arbitrary units (AU) and similarly compared across study sites and demographic information. Results: The P. falciparum infection rate and frequency of malaria were high in the study areas with significant age-dependent and inter-community differences, which were reflected by dif ferences in plasma levels of P. falciparum-specific IgG. Over 60% of households reported the use of bed nets and indoor insecticide sprays/coils, and 14% mentioned bush clearing around homes (14%) as malaria preventive measures. Community health centres were the preferred place for households (88%) to seek malaria treatment but over-the-counter drug stores were the major
  • Thumbnail Image
    Item
    Stepwise in vitro screening of MMV pathogen box compounds against Plasmodium falciparum to identify potent antimalarial candidates
    (International Journal for Parasitology: Drugs and Drug Resistance, 2023) Mbye, H.; Bojang, F.; Jaiteh, F.K.; et al.
    Development of resistance to deployed antimalarial drugs is inevitable and needs prompt and continuous dis covery of novel candidate drugs. Therefore, the antimalarial activity of 125 compounds from the Medicine for Malaria Ventures (MMV) pathogen box was determined. Combining standard IC50 and normalised growth rate inhibition (GR50) analyses, we found 16 and 22 compounds had higher potencies than CQ respectively. Seven compounds with relatively high potencies (low GR50 and IC50) against P. falciparum 3D7 were further analysed. Three of these were tested on 10 natural P. falciparum isolates from The Gambia using our newly developed parasite survival rate assay (PSRA). According to the IC50, GR50 and PSRA analyses, compound MMV667494 was most potent and highly cytotoxic to parasites. MMV010576 was slow acting but more potent than dihydroartemisinin (DHA) 72 h after exposure. MMV634140 was potent against the laboratory-adapted 3D7 isolate, but 4 out of 10 natural Gambian isolates survived and replicated slowly despite 72 h of exposure to the compound, suggesting potential drug tolerance and risk of resistance development. These results emphasise the usefulness of in vitro testing as a starting point for drug discovery. Improved approaches to data analyses and the use of natural isolates will facilitate the prioritisation of compounds for further clinical development.