Evaluation of Schistosoma mansoni in water sanitation and hygiene-based communities, and associated risk factors in Ogun Central, Nigeria

Schistosomiasis remains a major public health issue in Nigeria despite extensive Mass Drug Administration (MDA) and Water, Sanitation, and Hygiene (WASH) programmes. Persistent transmission in previously supported communities highlights gaps between available WASH infrastructure and sustained behavioural adherence. This study evaluates the current burden of Schistosoma mansoni and associated risk factors in WASH-supported communities in Ogun Central, Nigeria. A cross-sectional study was conducted in six communities with prior WASH interventions. Stool samples from 1,019 participants were examined using the Kato–Katz technique. Structured questionnaires assessed WASH knowledge, water-contact practices, and MDA compliance to identify risk factors and treatment fatigue. Prevalence was further examined across LGAs, age groups, school classes, and community-level characteristics to better understand heterogeneity in transmission. Overall prevalence of S. mansoni was 1.7%, with 12-year-old school-aged children showing the highest prevalence (2.9%). LGA-level prevalence peaked in Abeokuta North (3.0%) and Abeokuta South (2.8%), while Odeda recorded no infections. Community prevalence reached 10.7% in Ita-Iyalode and Iberekodo. Higher infection rates were associated with washing or recreational visits to rivers (3.6%), use of ventilated improved pit latrines (3.3%), geophagy (3.5%), and inconsistent footwear use. Pupils who had not been dewormed in the past 6 months showed a substantially higher prevalence (6.4%). No sex-based difference was observed. Schistosomiasis persists in WASH-supported communities due to continued risky water-contact behaviours, environmental exposures, and declining MDA participation. Strengthened behaviour-focused WASH interventions, targeted health education, and improved MDA uptake are essential to interrupt ongoing transmission.