Mapping risk factors and spatial clusters of schistosomiasis mansoni in rural communities from Brazil: three cross-sectional studies between 2014 and 2022.

This study aimed to determine the human positivity rate for S. mansoni infection and evaluate the association between socioeconomic factors and behavioral factors, as well as identify risk areas and changes in risk factors over the years 2014, 2015, and 2022 in rural communities in Brazil. We conducted three cross-sectional studies, included parasitological and malacological surveys, as well as risk questionnaires. To identify factors associated with S. mansoni infection, we used binomial generalized linear models. Spatial clusters of high-risk areas for S. mansoni infection were identified using Kernel and Flexible Spatial Scan. After anti-parasitic treatment and educational interventions, we observed a decline in prevalence from 2014 (45.9 %) to 2015 (10.38 %), followed by an increase to 26.03 % in 2022. Proximity to streams (<200 m) and lack of household bathrooms remained significant risk factors in both 2014 and 2022. In 2022, using untreated water also increased the odds of infection. A persistent high-risk cluster was identified in the Tocantins community across all years (relative risk: 2.03-4.18), where residents continue to rely on a contaminated stream due to incomplete water infrastructure projects. These findings reveal the limitations of control strategies based only on diagnosis and treatment. Persistent transmission in vulnerable areas underscores the urgent need for integrated public health actions. Sustainable progress toward schistosomiasis elimination requires not only treatment, but also universal access to clean water, improved sanitation, and targeted health education. High-risk clusters like Tocantins demand prioritized, multisectoral interventions to reduce health disparities and interrupt the cycle of reinfection.