Evaluation of ten (10) SARS-CoV-2 rapid serological tests in comparison with WANTAI SARS-CoV-2 ab ELISA in Burkina Faso, West Africa.

BACKGROUND: The aim of this study was to evaluate the performance of ten (10) SARS-CoV-2 serological rapid diagnostic tests in comparison with the WANTAI SARS-CoV-2 Ab ELISA test in a laboratory setting. MATERIALS AND METHODS: Ten (10) SARS-CoV-2 serological rapid diagnostic tests (RDTs) for SARS-CoV-2 IgG/IgM were evaluated with two (2) groups of plasma tested positive for one and negative for the other with the WANTAI SARS-CoV-2 Ab ELISA. The diagnostic performance of the SARS-CoV-2 serological RDTs and their agreement with the reference test were calculated with their 95% confidence intervals. RESULTS: The sensitivity of serological RDTs ranged from 27.39 to 61.67% and the specificity from 93.33 to 100% compared to WANTAI SARS-CoV-2 Ab ELISA test. Of all the tests, two tests (STANDARD Q COVID-19 IgM/IgG Combo SD BIOSENSOR and COVID-19 IgG/IgM Rapid Test (Zhejiang Orient Gene Biotech Co., Ltd)) had a sensitivity greater than 50%. In addition, all ten tests had specificity greater than or equal to 93.33% each. The concordance between RDTs and WANTAI SARS-CoV-2 Ab ELISA test ranged from 0.25 to 0.61. CONCLUSION: The SARS-CoV-2 serological RDTs evaluated show low and variable sensitivities compared to the WANTAI SARS-CoV-2 Ab ELISA test, with however a good specificity. These finding may have implications for the interpretation and comparison of COVID-19 seroprevalence studies depending on the type of test used.

Seasonal Malaria Chemoprevention Implementation: Effect on Malaria Incidence and Immunity in a Context of Expansion of P. falciparum Resistant Genotypes with Potential Reduction of the Effectiveness in Sub-Saharan Africa.

Seasonal Malaria Chemoprevention (SMC), which combines amodiaquine (AQ) with sulfadoxine-pyrimethamine (SP), is an effective and promising strategy, recommended by WHO, for controlling malaria morbidity and mortality in areas of intense seasonal transmission. Despite the effectiveness of this strategy, a number of controversies regarding the impact of the development of malaria-specific immunity and challenges of the strategy in the context of increasing and expanding antimalarial drugs resistance but also the limited coverage of the SMC in children make the relevance of the SMC questionable, especially in view of the financial and logistical investments. Indeed, the number of malaria cases in the target group, children under 5 years old, has increased while the implementation of SMC is been extended in several African countries. This ambivalence of the SMC strategy, the increase in the prevalence of malaria cases suggests the need to evaluate the SMC and understand some of the factors that may hinder the success of this strategy in the implementation areas. The present review discusses the impact of the SMC on malaria morbidity, parasite resistance to antimalarial drugs, molecular and the immunity affecting the incidence of malaria in children. This approach will contribute to improving the malaria control strategy in highly seasonal transmission areas where the SMC is implemented.

Comparative analysis of time-based and quadrat sampling in seasonal population dynamics of intermediate hosts of human schistosomes.

BACKGROUND: Despite their importance for designing and evaluating schistosomiasis control trials, little attention in the literature has been dedicated to sampling protocols for the parasite's snail intermediate hosts since their first development. We propose a comparative analysis of time-based and quadrat sampling protocols to quantify the seasonal variations in the abundance of these aquatic snail species of medical importance. METHODOLOGY/PRINCIPAL FINDINGS: Snail populations were monitored during 42 consecutive months in three types of habitats (ephemeral pond, ephemeral river and permanent stream) in two sites covering different climatic zones in Burkina Faso. We employed both a widely used time-based protocol of 30min of systematic collection at a weekly interval, and a quadrat protocol of 8 replicates per sample at a monthly interval. The correspondence between the two protocols was evaluated using an ensemble of statistical models including linear and saturating-type functional forms as well as allowing for count zero-inflation. The quadrat protocol yielded on average a relative standard error of 40%, for a mean snail density of 16.7 snails/m2 and index of dispersion of 1.51. Both protocols yielded similar seasonal patterns in snail abundance, confirming the asynchrony between permanent and ephemeral habitats with respect to the country's seasonal rainfall patterns. Formal model comparison of the link between time vs. quadrat counts showed strong support of saturation for the latter and measurement zero-inflation, providing important evidence for the presence of density feedbacks in the snail's population dynamics, as well as for spatial clustering. CONCLUSIONS/SIGNIFICANCE: In addition to the agreement with the time-based method, quadrat sampling provided insight into snail population dynamics and comparable density estimates across sites. The re-evaluation of these "traditional" sampling protocols, as well as the correspondence between their outputs, is of practical importance for the design and evaluation of schistosomiasis control trials.

Successful Control of Soil-Transmitted Helminthiasis in School Age Children in Burkina Faso and an Example of Community-Based Assessment via Lymphatic Filariasis Transmission Assessment Survey.

BACKGROUND: Burkina Faso is endemic with soil-transmitted helminth infections. Over a decade of preventive chemotherapy has been implemented through annual lymphatic filariasis (LF) mass drug administration (MDA) for population aged five years and over, biennial treatment of school age children with albendazole together with schistosomiasis MDA and biannual treatment of pre-school age children through Child Health Days. Assessments were conducted to evaluate the current situation and to determine the treatment strategy for the future. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional assessment was conducted in 22 sentinel sites across the country in 2013. In total, 3,514 school age children (1,748 boys and 1,766 girls) were examined by the Kato-Katz method. Overall, soil-transmitted helminth prevalence was 1.3% (95% CI: 1.0-1.8%) in children examined. Hookworm was the main species detected, with prevalence of 1.2% (95% CI: 0.9-1.6%) and mean egg counts of 2.1 epg (95% CI: 0-4.2 epg). Among regions, the Centre Ouest region had the highest hookworm prevalence of 3.4% (95% CI: 1.9-6.1%) and mean egg counts of 14.9 epg (95% CI: 3.3-26.6 epg). A separate assessment was conducted in the Centre Nord region in 2014 using community-based cluster survey design during an LF transmission assessment survey (TAS). In this assessment, 351 children aged 6-7 years and 345 children aged 10-14 years were examined, with two cases (0.6% (95% CI: 0.2-2.1%)) and seven cases (2.0% (95% CI: 1.0-4.1%)) of hookworm infection was identified respectively. The results using both age groups categorized the region to be 2% to <10% in STH prevalence according to the pre-defined cut-off values. CONCLUSIONS/SIGNIFICANCE: Through large-scale preventive chemotherapy, Burkina Faso has effectively controlled STH in school age children in the country. Research should be conducted on future strategies to consolidate the gain and to interrupt STH transmission in Burkina Faso. It is also demonstrated that LF TAS provides one feasible and efficient platform to assess the STH situation for post LF MDA decision making.

Schistosomiasis in school-age children in Burkina Faso after a decade of preventive chemotherapy.

OBJECTIVE: To assess the impact of a decade of biennial mass administration of praziquantel on schistosomiasis in school-age children in Burkina Faso. METHODS: In 2013, in a national assessment based on 22 sentinel sites, 3514 school children aged 7-11 years were checked for Schistosoma haematobium and Schistosoma mansoni infection by the examination of urine and stool samples, respectively. We analysed the observed prevalence and intensity of infections and compared these with the relevant results of earlier surveys in Burkina Faso. FINDINGS: S. haematobium was detected in 287/3514 school children (adjusted prevalence: 8.76%, range across sentinel sites: 0.0-56.3%; median: 2.5%). The prevalence of S. haematobium infection was higher in the children from the Centre-Est, Est and Sahel regions than in those from Burkina Faso's other eight regions with sentinel sites (P < 0.001). The adjusted arithmetic mean intensity of S. haematobium infection, among all children, was 6.0 eggs per 10 ml urine. Less than 1% of the children in six regions had heavy S. haematobium infections - i.e. at least 50 eggs per 10 ml urine - but such infections were detected in 8.75% (28/320) and 11.56% (37/320) of the children from the Centre-Est and Sahel regions, respectively. Schistosoma mansoni was only detected in two regions and 43 children - i.e. 1 (0.31%) of the 320 from Centre-Sud and 42 (8.75%) of the 480 from Hauts Bassins. CONCLUSION: By mass use of preventive chemotherapy, Burkina Faso may have eliminated schistosomiasis as a public health problem in eight regions and controlled schistosome-related morbidity in another three regions.

[Parasitological profile of two forms of schistosomiasis (urinary and intestinal forms) at ten sites in Burkina Faso (Sub-Saharan Africa country)]. / Profil parasitologique de deux formes de schistosomiase (formes urinaire et intestinale) dans dix sites du Burkina Faso (pays d'Afrique sub-saharienne).

In spite of great progress in schistosomiasis control during the last decade in Burkina Faso, this disease remains a public health concern in the country. Indeed, our study consisted of the analysis of parasitological data related to Schistosoma haematobium and Schistosoma mansoni and in malacological investigations. The prevalence rate of Schistosoma haematobium varies from 3.3% to 50.4% and from 3.3% to 39.1% for Schistosoma mansoni, but only in the western part of Burkina Faso. Schoolboys are more infested than girls, but the phenomenon is reversed in adults. Biomphalaria pfeifferi, Bulinus truncatus, Bulinus senegalensis and Bulinus globosus were collected during this study. Thus, the behavioral factors as well as the dynamics and the distribution of the intermediate mollusks play a major role in the persistence of the disease.