Current water contact and Schistosoma mansoni infection have distinct determinants: a data-driven population-based study in rural Uganda

Water contact is a key element of the system of human-environment interactions that determine individual exposure to schistosome parasites and, in turn, community transmission. Yet, there is a limited understanding of the complexity of water contact. We characterised patterns and determinants of water contact within the large-scale SchistoTrack study on 2867 individuals aged 5-90 years in Eastern and Western Uganda, employing Bayesian variable selection and advanced statistical modelling. We found a 15-year gap between the population-level peak in water contact (age 30) and infection (age 15) with practically no correlation (ρ = 0.03) between individual-level water contact and infection. Adults had higher water contact than children, and 80% of individuals with water contact lived within 0.43 km of water bodies. Domestic water contact was most common for children and women, while occupational water contact was most common for men. Water contact was positively associated with older age, fishing or fish mongering occupations, the number of water sites, and type (beach/pond/swamp), and lower village-level infection prevalence. Only older age and fishing were positively, though inconsistently, associated with infection status/intensity. By providing profiles of at-risk groups, and suitable water contact metrics, our research opens avenues for spatially-targeted interventions and exposure monitoring in endemic countries.