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Aims Schistosomiasis and malaria are endemic in sub-Saharan Africa where Schistosoma haematobium (Sh) and Plasmodium falciparum (Pf) coinfections are thus frequent. We explored the effect of Sh infection on antibody responses directed to Pf merozoite antigens and on malaria susceptibility in Beninese children. Methods and results A total of 268 children were followed during a malaria transmission season. Detection of Pf infection was performed by microscopy and rapid diagnostic tests. Sh infection was determined in urine by microscopy. Antimalarial antibody, cytokine and HLA-G concentrations were quantified by ELISA. The expression of HLA-G receptors by immune cells was assessed by flow cytometry. Children infected by Sh had higher concentrations of IgG1 directed to MSP3 and GLURP(R0), IgG2 directed to GLURP(R0) and IgG3 directed to MSP3, GLURP(R0) and GLURP(R2) and have lower Pf densities than those uninfected by Sh. No difference in cytokine and HLA-G concentrations was observed between Sh egg carriers and non-carriers. Conclusion Schistosoma haematobium modulates host immune responses directed to Pf antigens. The absence of immune downregulation usually observed during helminth infections is surprising in our study. We hypothesize that the stage of Sh development could partly explain the immune pathways leading to increased antibody levels that favour better control of Pf parasitemia.

Current control strategies for soil-transmitted helminths (STH) emphasize morbidity control through mass drug administration (MDA) targeting preschool- and school-age children, women of childbearing age and adults in certain high-risk occupations such as agricultural laborers or miners. This strategy is effective at reducing morbidity in those treated but, without massive economic development, it is unlikely it will interrupt transmission. MDA will therefore need to continue indefinitely to maintain benefit. Mathematical models suggest that transmission interruption may be achievable through MDA alone, provided that all age groups are targeted with high coverage. The DeWorm3 Project will test the feasibility of interrupting STH transmission using biannual MDA targeting all age groups. Study sites (population ≥80,000) have been identified in Benin, Malawi and India. Each site will be divided into 40 clusters, to be randomized 1:1 to three years of twice-annual community-wide MDA or standard-of-care MDA, typically annual school-based deworming. Community-wide MDA will be delivered door-to-door, while standard-of-care MDA will be delivered according to national guidelines. The primary outcome is transmission interruption of the STH species present at each site, defined as weighted cluster-level prevalence ≤2% by quantitative polymerase chain reaction (qPCR), 24 months after the final round of MDA. Secondary outcomes include the endline prevalence of STH, overall and by species, and the endline prevalence of STH among children under five as an indicator of incident infections. Secondary analyses will identify cluster-level factors associated with transmission interruption. Prevalence will be assessed using qPCR of stool samples collected from a random sample of cluster residents at baseline, six months after the final round of MDA and 24 months post-MDA. A smaller number of individuals in each cluster will be followed with annual sampling to monitor trends in prevalence and reinfection throughout the trial. TRIAL REGISTRATION: ClinicalTrials.gov NCT03014167.

HLA-G/E/F genes exhibit immunomodulatory properties and are expressed in placenta. Little attention has been devoted to the study of these genes in sub-Saharan African populations, which are yet the most diverse. To fill this gap, we evaluated the complete gene variability, approximately 5.1 kb for HLA-G (n = 149), 7.7 kb for HLAE (n = 150) and 6.2 kb for HLA-P (n = 152) in the remote Beninese Toffin population, using massive parallel sequencing. Overall, 96, 37 and 68 variable sites were detected along the entire HLA-G,-E and-F, respectively, arranged into region-specific haplotypes; i.e., promoter haplotypes (16, 19, and 15 respectively), coding haplotypes (19, 15, and 29 respectively), 3' untranslated region (3'UTR) haplotypes (12, 7 and 2, respectively) and extended haplotypes (33, 31 and 32 respectively). All promoter/coding/3'UTR haplotypes followed the patterns already described in worldwide populations. HLA-E was the most conserved, exhibiting mainly two full-length encoded-molecules (E*01:01 and E*01:03), followed by HLA-F, three full-length proteins (F*01:01, F*01:02 and F*01:03) and HLA-G, four proteins: three full-length (G*01:01, G*01:03 and G*01:04) and one truncated (G*01:05N). Although HLA-G/E/F alleles in the Toffin population were the most frequently observed worldwide, the frequencies of the coding haplotypes were closely similar to those described for other African populations (Guinea-Conakry and Burkina-Faso), when compared to non-African ones (Brazilian), indicating that variable sites along these genes were present in Africa before human dispersion.

The replacement of fishmeal (FM) with Azolla meal (AM) in diets on growth and fatty acid in Nile tilapia, Oreochromis niloticus (initial mean weight: 16.4 g) was studied. Fish were fed with six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ.g-1) diets containing 0%, 10%, 20%, 30%, 40% and 50% AM respectively, as partial FM substitute. Diet A0 acted as a control. The final weight (51.0-88.3 g), the weight gain (210.8-438.3%) and the SGR (1.3-1.9%day-1) decreased when AM level higher than 10% in diets (P < 0.05). The FCR (1.44 to 2.35) significantly increased when AM level exceeded 20% (P < 0.05). The protein efficiency ratio and the apparent net protein utilization decreased consequently. The fatty acids in the whole fish were significantly influenced by the diets. The replacement of FM by AM produced fish with lower (n-3) highly unsaturated fatty acids mainly docosahexaenoic acid, and higher arachidonic acid (P < 0.05). The n-3/n-6 fatty acid ratio ranged from 0.08 to 0.17, and was lower in fish fed A40 and A50 (P < 0.05). The findings suggest that high AM in diets affects Nile tilapia growth and the fern could be incorporated in diets up to 30% without any adverse effect on fish fatty acid composition. However, alternative additional source of lipid must be used to improve the quality of fish fed AM-diets.Keywords: Azolla, Fish meal replacement, Growth, Fatty acids, Oreochromis niloticus, bioconversion