Urinary schistosomiasis in three different water-access in the Senegal River Basin: monitoring praziquantel efficacy and re-infection levels

Abstract BackgroundSchistosomiasis is a neglected tropical disease most prevalent in sub-Saharan Africa countries. In the Senegal river basin, the construction of the Diama dam led to an increase and endemicity of schistosomiasis. Since 2009, praziquantel has frequently been used as preventive chemotherapy in the form of mass administration to Senegalese school-aged children, despite reports of low cure rates and possible resistance in certain endemic countries. This study aims to determine the current prevalence of S. haematobium, the efficacy of praziquantel, and the re-infection in children from five villages with different water access.MethodsThe baseline prevalence of S. haematobium was determined in August 2020 in 777 children between 5 and 11 years old. A single dose of praziquantel (40 mg/kg) was administered to those positive. The efficacy of praziquantel and re-infection rates were monitored four weeks and seven months after treatment, respectively, in 226 children with a high intensity of infection at baseline.ResultsPrevalence was lower among children from the village of Mbane who live close to the Lac de Guiers (37.92%), average among those from the villages of Dioundou and Khodit, which neighbour the Doue river (46%), and very high (over 90%) in Khodit and Guia which mainly use an irrigation canal. A significant difference in the prevalence and intensity of S. haematobium infection was noted between the different types of water access. The lowest cure rate (88.5%) was obtained in the village using the irrigation canal, while high cure rates (96.5% and 98%) and egg reduction rates (between 96.7% and 99.7%) were observed in all the villages. Re-infection was significantly higher in the village using the canal (42.5 %) than in the villages accessing the Lac de Guiers (18.3%) and the Doue river (14.8%).ConclusionPraziquantel (40 mg/kg) has an impact on reducing the prevalence and intensity of S. haematobium infection four weeks after treatment. However, in the Senegal river basin, S. haematobium remains a real health problem for children living in the villages near the irrigation canals, despite regular treatment, while prevalence is declining from those frequenting the river and the Lac de Guiers.Trial registration: ClinicalTrials.gov, NCT04635553. Registered 19 November 2020 retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT04635553?cntry=SN&draw=2&rank=4