Background Schistosomiasis is a parasitic disease responsible of important morbidity and mortality in sub-Saharan endemic countries. In Senegal, national schistosomiasis control and elimination program has initiated since 2012, annual repeated praziquantel (PZQ) mass drug administration (MDA) in endemic regions in the Senegal River basin (SRB). The impact of annual MDAs is assessed at the health district level. However, considering the focal characteristic of the disease transmission, huge disparities exist at the lowest levels, such as village or contamination site.

Methods This study consisted in following the Schistosoma haematobium infection using microscopic method in a cohort of school-age children in five villages in the SRB. Baseline prevalence was evaluated in August 2020 then 40 mg/kg of PZQ was administered. Six month after, the prevalence and reinfection were evaluated and a second treatment was administered in March 2021 following by a second prevalence and reinfection evaluation six months after.

Results At the baseline, very high prevalence was observed in the villages of Guia (91.2%) and Khodit (90.6%) with Human frequenting irrigation canal while moderate prevalence was noted in the village of Ndiawara (45%), and Dioundou (49%) with Human frequenting the river and also in the village of Mbane (43.1%) near the Lac de Guiers. After two six-months interval treatment, prevalence of Schistosoma haematobium was reduced in all the villages with the lowest reinfection rates noted in children frequenting the Senegal river (25.5%) and the lac de Guiers (36%), while the villages near the irrigation canal, remain hotspots with higher rates of reinfection in children (58%).

Conclusion This study suggests to adept the periodicity of the MDA in the SRB at a 6-month interval in the villages near the irrigation canals, while maintaining the annual treatment in the other villages in accordance with the WHO guideline on control and elimination of schistosomiasis.