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"Gaye, Oumar"
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There should be a World Health Assembly resolution for malaria eradication
2019
Several efforts are being made now for malaria elimination with a goal for eradication. New tools and strategies are being developed and there is currently renewed political engagement and interest. Several technical groups have produced a guide on elimination for policymakers and indicated different research questions to be addressed. The World Health Assembly resolution and the United Nations General Assembly convened a high-level roundtable “From High Burden to High Impact: Getting back on track to end Malaria”. In Africa, the Head of states pronounced a vision for an Africa free of malaria and launched the slogan “
Zero malaria starts with me
”. Massive efforts to sustain research capacity in the endemic countries will be critical. It will be important to both increase domestic financing, and advocate to sustain and increase funding from major donor countries. It is unethical to continue to observe deaths of so many children in malaria endemic countries, the most vulnerable populations. Considering malaria eradication as a vision and working with all the opportunities we now have could accelerate the process. Eliminating malaria with a country regional approach and progressing step by step will give us consistent information on our way towards eradication.
Journal Article
Avoiding Data Dumpsters — Toward Equitable and Useful Data Sharing
by
Guerin, Philippe J
,
Gaye, Oumar
,
Merson, Laura
in
Antimalarials - therapeutic use
,
Biomedical Research
,
Clinical Trials as Topic
2016
Now is the time to focus on developing effective, efficient, equitable, ethical practices for data sharing. Simply making more data openly available may not lead to analyses that are relevant and that are actually applied to improve health.
The potential health benefits from sharing participant-level clinical research data for the purpose of secondary analysis or meta-analysis have been widely touted. Although some researchers remain wary about sharing data, recent policies and proposals by funders, scientific journals, research institutions, and international health organizations mean that data sharing, in one form or another, is inevitable. Now is therefore the time to focus on developing practices for data sharing that are effective, efficient, equitable, and ethical. In the process, we may need to question the assumption that more is better. Simply making more data openly available may not lead to analyses . . .
Journal Article
Effectiveness of Seasonal Malaria Chemoprevention in Children under Ten Years of Age in Senegal: A Stepped-Wedge Cluster-Randomised Trial
by
Dial, Yankhoba
,
Sy, Ousmane
,
Cissé, Badara
in
Amodiaquine - therapeutic use
,
Anemia
,
Antimalarials - therapeutic use
2016
Seasonal Malaria Chemoprevention (SMC) with sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ), given each month during the transmission season, is recommended for children living in areas of the Sahel where malaria transmission is highly seasonal. The recommendation for SMC is currently limited to children under five years of age, but, in many areas of seasonal transmission, the burden in older children may justify extending this age limit. This study was done to determine the effectiveness of SMC in Senegalese children up to ten years of age.
SMC was introduced into three districts over three years in central Senegal using a stepped-wedge cluster-randomised design. A census of the population was undertaken and a surveillance system was established to record all deaths and to record all cases of malaria seen at health facilities. A pharmacovigilance system was put in place to detect adverse drug reactions. Fifty-four health posts were randomised. Nine started implementation of SMC in 2008, 18 in 2009, and a further 18 in 2010, with 9 remaining as controls. In the first year of implementation, SMC was delivered to children aged 3-59 months; the age range was then extended for the latter two years of the study to include children up to 10 years of age. Cluster sample surveys at the end of each transmission season were done to measure coverage of SMC and the prevalence of parasitaemia and anaemia, to monitor molecular markers of drug resistance, and to measure insecticide-treated net (ITN) use. Entomological monitoring and assessment of costs of delivery in each health post and of community attitudes to SMC were also undertaken. About 780,000 treatments were administered over three years. Coverage exceeded 80% each month. Mortality, the primary endpoint, was similar in SMC and control areas (4.6 and 4.5 per 1000 respectively in children under 5 years and 1.3 and 1.2 per 1000 in children 5-9 years of age; the overall mortality rate ratio [SMC: no SMC] was 0.90, 95% CI 0.68-1.2, p = 0.496). A reduction of 60% (95% CI 54%-64%, p < 0.001) in the incidence of malaria cases confirmed by a rapid diagnostic test (RDT) and a reduction of 69% (95% CI 65%-72%, p < 0.001) in the number of treatments for malaria (confirmed and unconfirmed) was observed in children. In areas where SMC was implemented, incidence of confirmed malaria in adults and in children too old to receive SMC was reduced by 26% (95% CI 18%-33%, p < 0.001) and the total number of treatments for malaria (confirmed and unconfirmed) in these older age groups was reduced by 29% (95% CI 21%-35%, p < 0.001). One hundred and twenty-three children were admitted to hospital with a diagnosis of severe malaria, with 64 in control areas and 59 in SMC areas, showing a reduction in the incidence rate of severe disease of 45% (95% CI 5%-68%, p = 0.031). Estimates of the reduction in the prevalence of parasitaemia at the end of the transmission season in SMC areas were 68% (95% CI 35%-85%) p = 0.002 in 2008, 84% (95% CI 58%-94%, p < 0.001) in 2009, and 30% (95% CI -130%-79%, p = 0.56) in 2010. SMC was well tolerated with no serious adverse reactions attributable to SMC drugs. Vomiting was the most commonly reported mild adverse event but was reported in less than 1% of treatments. The average cost of delivery was US$0.50 per child per month, but varied widely depending on the size of the health post. Limitations included the low rate of mortality, which limited our ability to detect an effect on this endpoint.
SMC substantially reduced the incidence of outpatient cases of malaria and of severe malaria in children, but no difference in all-cause mortality was observed. Introduction of SMC was associated with an overall reduction in malaria incidence in untreated age groups. In many areas of Africa with seasonal malaria, there is a substantial burden in older children that could be prevented by SMC. SMC in older children is well tolerated and effective and can contribute to reducing malaria transmission.
ClinicalTrials.gov NCT00712374.
Journal Article
Engaging United States Black Communities in HIV Pre-exposure Prophylaxis: Analysis of a PrEP Engagement Cascade
2018
National PrEP utilization analyses show US non-Hispanic Blacks accessing PrEP at disproportionately low rates given the higher HIV prevalence among Blacks, and in comparison to utilization by non-Hispanic Whites. Women also are underrepresented among PrEP utilizers, especially Black women. We examine the process of accessing PrEP for a majority Black population in an urban community health center setting.
In the Philadelphia city health centers, patients referred for PrEP were followed through six steps of accessing PrEP: referral, patient contact by a PrEP team, maintained interest by patients, scheduling of screening appointments, attending screening appointments, and initiating PrEP. Chi-squared tests were performed at each stage to identify gender differences in drop-off at each step.
Between August 2014 and December 2015, 14% of 785 patients referred for PrEP initiated. Women constituted 37.8% of referrals. A smaller majority of Blacks initiated (84.6% of females, 69.5% of males) than were referred (94.5% of females, 88.1% of males). Prior knowledge of PrEP was associated with screening (68% of those with prior knowledge screened, compared with 29.6% of those without prior knowledge,Χ2 p<0.0001). Higher initiation:referral ratios were noted for self-referrals, and for those referred by clinicians, peers and partners.
In a diverse cohort in a community health center setting, myriad barriers resulted in a 14% initiation rate for persons at elevated risk for HIV who were referred for PrEP. These barriers led to disproportionately fewer non-Hispanic Blacks and women initiating PrEP. Efforts to better engage Blacks and women in PrEP care are urgently needed, and may include better dissemination of PrEP-related information in Black communities and to women, and training of clinicians serving Black and female populations to improve competency in provision of PrEP care.
Journal Article
Seasonal malaria chemoprevention combined with community case management of malaria in children under 10 years of age, over 5 months, in south-east Senegal: A cluster-randomised trial
2019
Seasonal malaria chemoprevention (SMC) is recommended in the Sahel region of Africa for children under 5 years of age, for up to 4 months of the year. It may be appropriate to include older children, and to provide protection for more than 4 months. We evaluated the effectiveness of SMC using sulfadoxine-pyrimethamine plus amodiaquine given over 5 months to children under 10 years of age in Saraya district in south-east Senegal in 2011.
Twenty-four villages, including 2,301 children aged 3-59 months and 2,245 aged 5-9 years, were randomised to receive SMC with community case management (CCM) (SMC villages) or CCM alone (control villages). In all villages, community health workers (CHWs) were trained to treat malaria cases with artemisinin combination therapy after testing with a rapid diagnostic test (RDT). In SMC villages, CHWs administered SMC to children aged 3 months to 9 years once a month for 5 months. The study was conducted from 27 July to 31 December 2011. The primary outcome was malaria (fever or history of fever with a positive RDT). The prevalence of anaemia and parasitaemia was measured in a survey at the end of the transmission season. Molecular markers associated with resistance to SMC drugs were analysed in samples from incident malaria cases and from children with parasitaemia in the survey. SMC was well tolerated with no serious adverse reactions. There were 1,472 RDT-confirmed malaria cases in the control villages and 270 in the SMC villages. Among children under 5 years of age, the rate difference was 110.8/1,000/month (95% CI 64.7, 156.8; p < 0.001) and among children 5-9 years of age, 101.3/1,000/month (95% CI 66.7, 136.0; p < 0.001). The mean haemoglobin concentration at the end of the transmission season was higher in SMC than control villages, by 6.5 g/l (95% CI 2.0, 11; p = 0.007) among children under 5 years of age, and by 5.2 g/l (95% CI 0.4, 9.9; p = 0.035) among children 5-9 years of age. The prevalence of parasitaemia was 18% in children under 5 years of age and 25% in children 5-9 years of age in the control villages, and 5.7% and 5.8%, respectively, in these 2 age groups in the SMC villages, with prevalence differences of 12.5% (95% CI 6.8%, 18.2%; p < 0.001) in children under 5 years of age and 19.3% (95% CI 8.3%, 30.2%; p < 0.001) in children 5-9 years of age. The pfdhps-540E mutation associated with clinical resistance to sulfadoxine-pyrimethamine was found in 0.8% of samples from malaria cases but not in the final survey. Twelve children died in the control group and 14 in the SMC group, a rate difference of 0.096/1,000 child-months (95% CI 0.99, 1.18; p = 0.895). Limitations of this study include that we were not able to obtain blood smears for microscopy for all suspected malaria cases, such that we had to rely on RDTs for confirmation, which may have included false positives.
In this study SMC for children under 10 years of age given over 5 months was feasible, well tolerated, and effective in preventing malaria episodes, and reduced the prevalence of parasitaemia and anaemia. SMC with CCM achieved high coverage and ensured children with malaria were promptly treated with artemether-lumefantrine.
www.clinicaltrials.gov NCT01449045.
Journal Article
Mapping the breeding sites of Anopheles gambiae s. l. in areas of residual malaria transmission in central western Senegal
by
Sy, Ousmane
,
Gaye, Oumar
,
Faye, Ousmane
in
Animals
,
Anopheles
,
Anopheles - growth & development
2020
Despite the deployment of several effective control interventions in central-western Senegal, residual malaria transmission is still occurring in some hotspots. To better tailor targeted control actions, it is critical to unravel the underlying environmental and geographical factors that cause the persistence infection in hotspot villages. “Hotspots villages” were defined in our study as those reporting more than six indigenous malaria cases during the previous year. A total of ten villages, including seven hotspots and three non-hotspots, were surveyed. All potential mosquito breeding sites identified in and around the ten study villages were regularly monitored between 2013 and 2017. Monitoring comprised the detection of anopheline larvae and the collection of epidemiological, hydrogeological, topographical, and biogeographical data. The number of larval breeding sites described and monitored during the study period ranged from 50 to 62. Breeding sites were more numerous in hotspot sites in each year of monitoring, with 90.3% (56/62) in 2013, 90.9% (50/55) in 2014, 90.3% (56/62) in 2015 and 86% (43/50) in 2017 (Fisher exact test; p = 1). In the non-hotspot areas, the data for the same years were, respectively, 9.7% (6/62), 9.1% (5/55), 9.7% (6/62) and 14% (7/50) (p = 1). The Hotspot villages were characterized mostly by saline or moderately saline hydro-morphic and halomorphic soils allowing water retention and a potential larval breeding sites. By contrast, non-hotspot villages were characterized mainly by a high proportion of extremely permeable sandy-textured soils, which due to their porosity had low water retention. The annual number of confirmed malaria cases was correlated with the frequency and extent of breeding sites. Malaria cases were significantly more frequent in the hamlets located near breeding sites of An . gambiae s.l., gradually decreasing with increasing remoteness. This study shows that the characteristics of larval breeding sites, as measured by their longevity, stability, proximity to human habitation, and their positivity in Anopheles larvae are likely determining factors in the persistence of malaria hotspots in central-western Senegal. The results of this study shed more light on the environmental factors underlying the residual transmission and should make it possible to better target vector control interventions for malaria elimination in west-central Senegal.
Journal Article
Prevalence and associated factors of schistosomiasis among pregnant women in northern Senegal
2024
Background
Schistosomiasis remains a public health concern worldwide. It is responsible for more than 240 million cases in 78 countries, 40 million of whom are women of childbearing age. In the Senegal River basin, both
Schistosoma haematobium
and
Schistosoma mansoni
are very prevalent in school-age children. However, there is a lack of information on the burden of schistosomiasis in pregnant women, which can cause complications in the pregnancy outcome. This study aimed to determine the prevalence and associated factors of schistosomiasis in pregnant women.
Methods
We conducted a prospective cross-sectional study of pregnant women attending antenatal clinics at the health center of the Senegalese Sugar Company and at the hospital of Richard Toll between August and December 2021. The urine and stool samples collected were examined using microscopy techniques and quantitative polymerase chain reaction (qPCR) to detect the presence of
S. haematobium
and
S. mansoni
. The urines were previously tested using urine reagent strips to detect hematuria and proteinuria. Socio-demographical, clinical, and diagnostically data were recorded by the midwife and the gynaecologist. The data were analyzed using a logistic regression model.
Results
Among the 298 women examined for the infection by microscopic, 65 (21.81%) were infected with urogenital schistosomiasis, 10 (3.36%) with intestinal schistosomiasis, and 4 (1.34%) were co-infected with both types of schistosomiasis. Out of the 288 samples tested by qPCR, 146 (48.99%) were positive for
S. haematobium
, 49 (35.51%) for
S. mansoni
and 22 (15.94%) for both species (co-infection). Pregnant women having microscopic haematuria and proteinuria were significantly more infected (
p
< 0.05).
Conclusion
This study has revealed a high prevalence of schistosomiasis in pregnant women in Senegal. The qPCR allowed us to detect more cases compared to the microscopy. There is a need to conduct more studies to understand the real burden of the disease and to set up a surveillance system to prevent pregnancy-related complications.
Journal Article
Characterization of the swarming behavior of Anopheles coluzzii and Anopheles gambiae (Diptera: Culicidae) populations in a hybrid zone of Senegal
by
Sy, Ousmane
,
Wondji, Charles Sinclair
,
Faye, Ousmane
in
Animals
,
Anopheles
,
Anopheles - genetics
2023
Anopheles gambiae and Anopheles coluzzii, often found in sympatry and synchronous, have undergone a premating reproductive isolation across their distribution range. However, in the Western coast of Africa, unexpected hybridization zones have been observed, and little is known about swarming behavior of these cryptic taxa. Here, we characterized the swarming behavior of An. coluzzii and An. gambiae to investigate its role in the high hybridization level in Senegal. The study was conducted in the south and central Senegal during the 2018 rainy season. Mating swarms of malaria vectors were surveyed at sunset and collected using an insect net. Meanwhile, indoor resting populations of malaria vectors were collected by pyrethrum spray catches. Upon collection, specimens were identified morphologically, and then members of the An. gambiae complex were identified at the species level by polymerase chain reaction (PCR). An. gambiae swarmed mainly over bare ground, whereas An. coluzzii were found swarming above various objects creating a dark–light contrast with the bare ground. The swarms height varied from 0.5 to 2.5 m. Swarming starting time was correlated with sunset whatever the months for both species, and generally lasted about 10 min. No mixed swarm of An. gambiae and An. coluzzii was found even in the high hybridization area. These results indicated a premating isolation between An. coluzzii and An. gambiae. However, the high hybridization rate in the sympatric area suggests that heterogamous mating is occurring, thus stressing the need for further extensive studies.
Journal Article
Spatiotemporal analysis of Anopheles gambiae larval sites and malaria transmission in Djilakh, Central Senegal
by
Sy, Ousmane
,
Diallo, Abdoulaye
,
Faye, Ousmane
in
Biodiversity hot spots
,
Breeding sites
,
Clay
2025
BackgroundThe progress made against malaria has resulted in a nationwide reduction of the disease burden in Senegal. The observed overall low transmission levels are, however, marked by an important spatial heterogeneity with hotspots subsisting in several parts of the country. This requires the determination of the local and regional factors of the observed disparities for tailored interventions to accelerate malaria elimination everywhere. This study aimed to demonstrate the role of larval breeding sites on malaria epidemiological trends in Djilakh, which is one of the malaria hotspots of the Mbour health district.MethodsThis study was carried out between 2013 and 2017, during the rainy season (June-November) of each year and surveys per year. The malaria incidence consisted of cases confirmed by RDT and climate data, including the rainfall were retrieved from the Mbour weather station. To assess the impact of larval breeding sites on malaria transmission in Djilakh village, logistic regression under the Poisson models were run. The QGIS 2.2.0 free mapping software was used to generate maps.ResultsThe results showed that mosquito breeding sites found within and in the vicinity of the study village consisted of natural temporary ponds, characterized by clay and clay-sandy soils. The analysis of meteorological and malaria morbidity indicated that malaria transmission is influenced by precipitation. The correlation between malaria morbidity and functioning breeding sites varied throughout the rainy season, depending on the size and stability of the existing breeding sites. The incidence of malaria cases was significantly higher (82.4%; 103/125; P < 0.011; OR = 27.006) in hamlets closer to the breeding sites (less than 500 m), declining gradually with distance with 17.6% (22/125) of the cases recorded in hamlets located between 500 and 1000 m apart from the larval habitats and, no cases in the most remote hamlets (> 1000 m).ConclusionsThese findings represent a preliminary step towards a better understanding of how the environmental factors influence the persistence of malaria transmission in the studied hotspot villages in Senegal. The generated results indicate a need for targeted control actions in the studied site.
Journal Article
Implementation, coverage and equity of large-scale door-to-door delivery of Seasonal Malaria Chemoprevention (SMC) to children under 10 in Senegal
by
Dial, Yankhoba
,
Gomis, Jules-Francois
,
Faye, Ernest
in
692/308/575
,
692/700/1538
,
Chemoprevention - statistics & numerical data
2018
SMC has been introduced widely in the Sahel since its recommendation by WHO in 2012. This study, which provided evidence of feasibility that supported the recommendation, included school-age and pre-school children. School-age children were not included in the 2012 recommendation but bear an increasing proportion of cases. In 2006, consultations with health-staff were held to choose delivery methods. The preferred approach, door-to-door with the first daily-dose supervised by a community-health-worker (CHW), was piloted and subsequently evaluated on a large-scale in under-5’s in 2008 and then in under-10’s 2009–2010. Coverage was higher among school-age children (96%(95%CI 94%,98%) received three treatments in 2010) than among under 5’s (90%(86%,94%)). SMC was more equitable than LLINs (odds-ratio for increase in coverage for a one-level rise in socioeconomic-ranking (a 5-point scale), was 1.1 (0.95,1.2) in 2009, compared with OR 1.3 (1.2,1.5) for sleeping under an LLIN. Effective communication was important in achieving high levels of uptake. Continued training and supervision were needed to ensure CHWs adhered to treatment guidelines. SMC door-to-door can, if carefully supervised, achieve high equitable coverage and high-quality delivery. SMC programmes can be adapted to include school-age children, a neglected group that bears a substantial burden of malaria.
Journal Article