Browsing by Author "Owusu, E.D.A."
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Item Acceptance and perceived value of non‑invasive malaria diagnostic tests in malaria‑endemic countries(Springer Nature, 2021) Owusu, E.D.A.; Campillo, A.; Daily, J.; Ding, X.C.Background: The diagnosis of malaria, using microscopy or rapid diagnostic tests (RDTs), requires the collection of capillary blood. This procedure is relatively simple to perform but invasive and poses potential risks to patients and health workers, arising from the manipulation of potentially infectious bodily fluids. Less or non-invasive diagnostic tests, based on urine, saliva or requiring no sampling, have the potential to generate less discomfort for the patient and to offer simpler and less risky testing procedures that could be safely performed by untrained staff or even selfperformed. To explore the potential acceptance and perceived value of such non-invasive tests, an online, international survey was conducted to gather feedback from National Malaria Control Programme (NMCP) representatives. Methods: An online survey comprising nineteen questions, available in English, French or Spanish, was emailed to 300 individuals who work with NMCPs in malaria-endemic countries. Answers were collected between November and December 2017; responses were qualitatively analysed to identify key themes and trends and quantitatively analysed to determine average values stratified by region. Results: Responses were received from 70 individuals, from 33 countries. Approximately half of the respondents (52 %) considered current blood-based tests for malaria to be minimally invasive and non-problematic in their setting. For these participants, non-invasive tests would only be of interest if they brought additional performance improvements, as compared with the performance of microscopy and RDTs. Most respondents were of the view that salivabased (80 %) and urine-based (66 %) tests would be more readily acceptable among children than blood-based tests. Potential use-case scenarios of interest for both saliva- and urine-based tests were ease-of-testing by community health workers, additional surveillance, self-testing, and outbreak investigation. Many respondents (41 %) thought that if saliva-based tests retailed at <$0.50 per unit they could largely replace conventional RDTs, whereas only 25 % of respondents thought a similarly priced urine-based test would do so. Conclusions: Although limited to NMCP stakeholders, this survey indicated that current tests for malaria, based on capillary blood, are generally perceived to be minimally invasive and non-problematic. Non-invasive tests, especially if saliva-based, would be welcome if they could match or out-perform the price and performance of current bloodbased tests.Item Characteristics of asymptomatic Plasmodium spp. parasitaemia in Kwahu-Mpraeso, a malaria endemic mountainous district in Ghana, West Africa(2016-01-22) Owusu, E.D.A.; Buabeng, V.; Dadzie, S.; Brown, C.A.; Grobusch, M.P.; Mens, P.Abstract Background Malaria control efforts in Ghana have reduced the countrywide average malaria prevalence from 71 % in 2000 to about 51 % in 2012; however, its main focus is on symptomatic malaria. If further progress is to be made, parasite reservoirs in asymptomatic carriers need to be moved into focus. This study profiles asymptomatic Plasmodium spp. parasitaemia amongst residents of mountainous Kwahu-Mpraeso in the Eastern region of Ghana. Methods A cross-sectional study of 360 residents was carried out from October to December 2013. This included recording demographics, malaria testing of asymptomatic residents, and gathering of their malaria history. Assessment of malaria transmission was done with molecular identification of vectors, determination of sporozoite rate, insecticide resistance status and biting pattern. Univariate and multivariate analysis were used to establish risk determinants. Results In Mpraeso, in the Kwahu highland of Eastern Region, children were at higher risk of asymptomatic parasitaemia, thereby contributing to the parasite reservoir and hence sustained malaria transmission. As well, findings suggested Hb AC genotype influenced susceptibility to asymptomatic malaria with 8.03-fold increase in odds (univariate) and 11.92-fold higher odds (multivariate) than the normal Hb AA. The mosquito vector predominant in the area was Anopheles gambiae sensu stricto of the homozygous pyrethroid resistant form (RR); with biting mainly occurring indoors. Conclusion For an effective malaria control in this area, interventions should be formulated and implemented to target asymptomatic parasite reservoirs; especially in children and people with Hb AC. The dominant vector species An. gambiae s.s. and its feeding patterns of biting indoors should also be considered.Item Circulating cell-free DNA integrity as a diagnostic and prognostic marker for breast and prostate cancers(Cancer Genetics, 2019-04) Arko-Boham, B.; Aryee, N.A.; Blay, R.M.; Owusu, E.D.A.; Tagoe, E.A.; Doris Shackie, E.S.; Debrah, A.B.; Adu-Aryee, N.A.Background Cancer incidence and its related mortality is rising and is currently the second leading cause of death globally. In Africa, breast and prostate cancer in females and males, respectively, are the worst globally. However, biomarkers for their early detection and prognosis are not well developed. This study sought to investigate circulating cell-free DNA (ccfDNA) integrity and its potential utility as diagnostic and/or prognostic biomarker. Circulating cell-free DNA (ccfDNA) is degraded DNA fragments released into the blood plasma. In healthy individuals, the source of ccfDNA is solely apoptosis, producing evenly sized shorter DNA fragments. In cancer patients, however, necrosis produces uneven longer cell-free DNA fragments in addition to the shorter fragments originating from apoptosis. DNA integrity, expressed as the ratio of longer fragments to total DNA, may be clinically useful for the detection of breast and prostate cancer progression. Methods Sixty-four (64) females, consisting of 32 breast cancer patients and 32 controls, and 61 males (31 prostate cancer patients and 30 controls) were included in the study. Each participant donated 5 ml peripheral blood from which sera were separated. Real-time qPCR was performed on the sera to quantify ALU 115 and 247 levels, and DNA integrity (ALU247/ALU115) determined. Results & Conclusion ALU species 115 and 247 levels in serum were elevated in breast and prostate cancer patients compared to their counterpart healthy controls. DNA integrity was higher in prostate cancer patients than in the control, but in breast cancer patients was lower compared to their controls. In prostate but not in breast cancers, DNA integrity increased with disease severity and higher staging.Item Corrigendum to “Knowledge, attitudes and practices regarding malaria in people living with HIV in rural and urban Ghana” [Acta Trop. 181 (2018) 16–20](Acta Tropica, 2019-04) Owusu, E.D.A.; Cremers, A.L.; Brown, C.A.; Mens, P.F.; Grobusch, M.P.The authors regret that there were errors in the p-values of Tables 1, 2, 3 [table-presented] and that Table 4 [table-presented] was not visually optimally presented. The corrected tables are provided below. The authors would like to apologise for any inconvenience caused and to point out that the corrected details do not impact on Results or Discussion as initially presented. © 2019 Elsevier B.V.Item Infammatory cytokines as potential biomarkers for early diagnosis of severe malaria in children in Ghana(Malaria Journal, 2023) Obeng‑Aboagye, E.; Frimpong, A.; Amponsah, J.A.; Danso, S.E.; Owusu, E.D.A.; Ofori, M.F.Background Severe malaria (SM) is a fatal multi-system disease which accounted for an estimated 619,000 deaths in 2021. Less than 30% of children presenting with SM are diagnosed and treated promptly, resulting in increased mortality and neurologic impairments in survivors. Studies have identifed cytokine profles that diferentiate the vari‑ ous clinical manifestations of malaria (severe and uncomplicated). However, the diagnostic capability of these cytokines in diferentiating between the disease states in terms of cut-of values has not yet been determined. Methods The plasma levels of 22 pro-infammatory cytokines (Eotaxin/CCL 11, interferon-gamma (IFN-γ), interleukin (IL)- 2, IL-6, IL-1β, IL-12p40/p70, IL-17A, RANTES, MCP-1, IL-15, IL-5, IL-1RA, IL-2R, IFN-α, IP-10, TNF, MIG, MIP-1α, MIP-1β, IL-7, IL-8 and Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF), and 3 anti-infammatory cytokines (IL-4, IL-13 and IL-10) in patients with SM, uncomplicated malaria (UM) and other febrile conditions, were measured and compared using the Human Cytokine Magnetic 25-Plex Panel. The receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of these cytokines. Results The level of the pro-infammatory cytokine, IL-17A, was signifcantly higher in the SM group as compared to the UM group. Levels of the anti-infammatory cytokines however did not difer signifcantly among the SM and UM groups. Only IL-1β and IL-17A showed good diagnostic potential after ROC curve analysis. Conclusion The data show that levels of pro-infammatory cytokines correlate with malaria disease severity. IL-1β and IL-17A showed good diagnostic potentials and can be considered for use in clinical practice to target treatment.Item The interaction between sickle cell disease and HIV infection: A systematic review(Clinical Infectious Diseases, 2014-10) Owusu, E.D.A.; Visser, B.J.; Nagel, I.M.; Mens, P.F.; Grobusch, M.P.Human immunodeficiency virus (HIV) and sickle cell disease (SCD) are regarded as endemic in overlapping geographic areas; however, for most countries only scarce data on the interaction between HIV and SCD and disease burden exist. HIV prevalence in SCD patients varies between 0% and 11.5% in published studies. SCD has been suggested to reduce disease progression of HIV into AIDS. Various interactions of antiretroviral therapy with SCD exist. Both SCD and HIV act as common risk factors for stroke, avascular necrosis, severe splenic dysfunction, pulmonary arterial hypertension, and sepsis, which may result in synergistic increase in risk of developing these diseases. No treatment guidelines regarding SCD with HIV coinfection were identified. Available evidence is mainly based on small clinical studies, thus making strong recommendations difficult. An increased effort to elucidate the precise interactions is warranted to better understand both diseases and effect more adequate treatment approaches, especially in view of their geographical coprevalence. © The Author 2014.Item Knowledge, attitudes and practices regarding malaria in people living with HIV in rural and urban Ghana(Elsevier B.V., 2018-05) Owusu, E.D.A.; Cremers, A.L.; Brown, C.A.; Mens, P.F.; Grobusch, M.P.Background: One of the malaria vulnerable groups is people living with HIV. This study investigated knowledge, attitude and practices (KAP) towards malaria in people living with HIV attending anti-retroviral therapy (ART) clinics in rural and urban Ghana. Methods: In this descriptive cross-sectional study patients attending the ART clinics in Atibie (rural area) and Accra (urban area) were interviewed on their knowledge, attitude and practices regarding malaria. Finger-prick capillary blood was tested for Plasmodium spp. with rapid diagnostic tests. Multivariate regression analysis was used to determine the influence of KAP on malaria prevalence. Results: Parasitemia was generally more frequent among HIV positive individuals in the rural area (29/116; 25%) in the rural area than in the urban area (35/350; 10%). Inaccurate knowledge of cause of malaria and prevention methods were associated with increased odds of malaria parasitemia; [OR = 1.51 (CI: 1.29–5.12); p < .05] and [OR = 2.59 (CI: 2.53–4.75); p < .05], respectively. There were disparities in socio-economic factors. For instance, low level of education was higher in the rural area (45/116; 38.8%) compared to the urban area (121/350; 34.6%). Conclusions: Malaria control efforts may yield further results when the knowledge and socio-economic gap between rural and urban areas is closed. © 2018 Elsevier B.V.Item Patient-level performance evaluation of a smartphone-based malaria diagnostic application(Malaria Journal, 2023) Yu, H.; Mohammed, F.O.; Hamid, M.A.; Owusu, E.D.A.; Yerlikaya, S.; Dittrich, S.; Jaeger, S.; et al.Background Microscopic examination is commonly used for malaria diagnosis in the feld. However, the lack of well-trained microscopists in malaria-endemic areas impacted the most by the disease is a severe problem. Besides, the examination process is time-consuming and prone to human error. Automated diagnostic systems based on machine learning ofer great potential to overcome these problems. This study aims to evaluate Malaria Screener, a smartphone-based application for malaria diagnosis. Methods A total of 190 patients were recruited at two sites in rural areas near Khartoum, Sudan. The Malaria Screener mobile application was deployed to screen Giemsa-stained blood smears. Both expert microscopy and nested PCR were performed to use as reference standards. First, Malaria Screener was evaluated using the two reference standards. Then, during post-study experiments, the evaluation was repeated for a newly developed algorithm, PlasmodiumVF-Net. Results Malaria Screener reached 74.1% (95% CI 63.5–83.0) accuracy in detecting Plasmodium falciparum malaria using expert microscopy as the reference after a threshold calibration. It reached 71.8% (95% CI 61.0–81.0) accuracy when compared with PCR. The achieved accuracies meet the WHO Level 3 requirement for parasite detection. The processing time for each smear varies from 5 to 15 min, depending on the concentration of white blood cells (WBCs). In the post-study experiment, Malaria Screener reached 91.8% (95% CI 83.8–96.6) accuracy when patient-level results were calculated with a diferent method. This accuracy meets the WHO Level 1 requirement for parasite detection. In addition, PlasmodiumVF-Net, a newly developed algorithm, reached 83.1% (95% CI 77.0–88.1) accuracy when compared with expert microscopy and 81.0% (95% CI 74.6–86.3) accuracy when compared with PCR, reaching the WHO Level 2 requirement for detecting both Plasmodium falciparum and Plasmodium vivax malaria, without using the testing sites data for training or calibration. Results reported for both Malaria Screener and PlasmodiumVF-Net used thick smears for diagnosis. In this paper, both systems were not assessed in species identification and parasite counting, which are still under development.Item Patient-level performance evaluation of a smartphone-based malaria diagnostic application(Malaria Journal, 2023) Yu, H.; Mohammed, F.O.; Hamid, M.A.; Fang, F.; Kassim, Y.M.; Mohamed, A.O.; Maude, R.J.; Ding, X.C.; Owusu, E.D.A.; Yerlikaya, S.; Dittrich, S.; Jaeger, S.Background Microscopic examination is commonly used for malaria diagnosis in the field. However, the lack of well-trained microscopists in malaria-endemic areas impacted the most by the disease is a severe problem. Besides, the examination process is time-consuming and prone to human error. Automated diagnostic systems based on machine learning ofer great potential to overcome these problems. This study aims to evaluate Malaria Screener, a smartphone-based application for malaria diagnosis. Methods A total of 190 patients were recruited at two sites in rural areas near Khartoum, Sudan. The Malaria Screener mobile application was deployed to screen Giemsa-stained blood smears. Both expert microscopy and nested PCR were performed to use as reference standards. First, Malaria Screener was evaluated using the two reference standards. Then, during post-study experiments, the evaluation was repeated for a newly developed algorithm, PlasmodiumVF-Net. Results Malaria Screener reached 74.1% (95% CI 63.5–83.0) accuracy in detecting Plasmodium falciparum malaria using expert microscopy as the reference after a threshold calibration. It reached 71.8% (95% CI 61.0–81.0) accuracy when compared with PCR. The achieved accuracies meet the WHO Level 3 requirement for parasite detection. The processing time for each smear varies from 5 to 15 min, depending on the concentration of white blood cells (WBCs). In the post-study experiment, Malaria Screener reached 91.8% (95% CI 83.8–96.6) accuracy when patient-level results were calculated with a different method. This accuracy meets the WHO Level 1 requirement for parasite detection. In addition, PlasmodiumVF-Net, a newly developed algorithm, reached 83.1% (95% CI 77.0–88.1) accuracy when compared with expert microscopy and 81.0% (95% CI 74.6–86.3) accuracy when compared with PCR, reaching the WHO Level 2 requirement for detecting both Plasmodium falciparum and Plasmodium vivax malaria, without using the testing sites data for training or calibration. Results reported for both Malaria Screener and PlasmodiumVF-Net used thick smears for diagnosis. In this paper, both systems were not assessed in species identifcation and parasite counting, which are still under development.Item Plasmodium falciparum diagnostic tools in HIV-positive under-5-year-olds in two ART clinics in Ghana: are there missed infections?(Malaria Journal, 2018-02) Owusu, E.D.A.; Djonor, S.K.; Brown, C.A.; Grobusch, M.P.; Mens, P.F.Background Plasmodium falciparum, the most dominant species in sub-Saharan Africa, causes the most severe clinical malaria manifestations. In resource-limited Ghana, where malaria and HIV geographically overlap, histidine-rich protein 2 (HRP2)-based rapid diagnostic test (RDT) is a faster, easier and cheaper alternative to clinical gold standard light microscopy. However, mutations in parasite hrp2 gene may result in missed infections, which have severe implications for malaria control. Methods The performance of a common HRP2-based RDT and expert light microscopy in HIV-positive and HIV-negative children under 5 years old was compared with PCR as laboratory gold standard. Finger-prick capillary blood was tested with First Response® Malaria Ag P. falciparum (HRP2). Giemsa-stained thick and thin blood films were examined with ≥ 200 high power fields and parasites counted per 200 white blood cells. Nested PCR species identification of P. falciparum was performed and resolved on agarose gel. False negatives from RDT were further tested for deleted pfhrp2/3 and flanking genes, using PCR. The study was performed in two anti-retroviral therapy clinics in Accra and Atibie. Results Out of 401 participants enrolled, 150 were HIV positive and 251 HIV negative. Malaria was more prevalent in children without HIV. Microscopy had a higher sensitivity [100% (99–100)] than RDT [83% (53.5–100)]. Parasites with pfhrp2/3 deletions contributed to missed infections from RDT false negatives. Conclusion Circulation of malaria parasites with pfrhp2/3 deletions in this population played a role in missed infections with RDT. This ought to be addressed if further strides in malaria control are to be made.Item Safety and effectiveness of antimalarial therapy in sickle cell disease: a systematic review and network meta-analysis(BMC Infectious Diseases, 2018-12) Frimpong, A.; Thiam, L.G.; Arko-Boham, B.; Owusu, E.D.A.; Adjei, G.O.Background About 80% of all reported sickle cell disease (SCD) cases in children anually are recorded in Africa. Although malaria is considered a major cause of death in SCD children, there is limited data on the safety and effectiveness of the available antimalarial drugs used for prophylaxis. Also, previous systematic reviews have not provided quantitative measures of preventive effectiveness. The purpose of this research was to conduct a systematic review and meta-analysis of the available literature to determine the safety and effectiveness of antimalarial chemoprophylaxis used in SCD patients. Methods We searched in PubMed, Medline, CINAHL, POPLine and Cochrane library, for the period spanning January 1990 to April 2018. We considered randomized or quasi-randomized controlled trials comparing any antimalarial chemoprophylaxis to, 1) other antimalarial chemoprophylaxis, 2) placebo or 3) no intervention, in SCD patients. Studies comparing at least two treatment arms, for a minimum duration of three months, with no restriction on the number of patients per arm were reviewed. The data were extracted and expressed as odds ratios. Direct pairwise comparisons were performed using fixed effect models and the heterogeneity assessed using the I-square. Results Six qualified studies that highlighted the importance of antimalarial chemoprophylaxis in SCD children were identified. In total, seven different interventions (Chloroquine, Mefloquine, Mefloquine artesunate, Proguanil, Pyrimethamine, Sulfadoxine-pyrimethamine, Sulfadoxine-pyrimethamine amodiaquine) were evaluated in 912 children with SCD. Overall, the meta-analysis showed that antimalarial chemoprophylaxis provided protection against parasitemia and clinical malaria episodes in children with SCD. Nevertheless, the risk of hospitalization (OR = 0.72, 95% CI = 0.267–1.959; I2 = 0.0%), blood transfusion (OR = 0.83, 95% CI = 0.542–1.280; I2 = 29.733%), vaso-occlusive crisis (OR = 19, 95% CI = 1.713–2.792; I2 = 93.637%), and mortality (OR = 0.511, 95% CI = 0.189–1.384; I2 = 0.0%) did not differ between the intervention and placebo groups. Conclusion The data shows that antimalarial prophylaxis reduces the incidence of clinical malaria in children with SCD. However, there was no difference between the occurrence of adverse events in children who received placebo and those who received prophylaxis. This creates an urgent need to assess the efficacy of new antimalarial drug regimens as potential prophylactic agents in SCD patients.