Ecological Determinants and Spatial Distribution of Schistosoma Intermediate Host Snails in Kimpese Region, in the Democratic Republic of the Congo

Schistosomiasis intermediate host snails’ data in the Democratic Republic of the Congo are limited and geographically dispersed. The objective of this study was to characterize snail habitats and identify environmental determinants of their presence. Monthly malacological surveys were conducted at 72 water contact sites. The morphological identification of the snails was complemented by the sequencing of the mitochondrial cox1 gene in order to guarantee confirmation of the species. The physicochemical parameters of the water, as well as human activities on the site, were recorded. The associations between environmental characteristics and snail presence were evaluated using generalized estimating equation models to account for repeated measurements. A total of 172,491 snails were collected, including 4,899 Schistosoma intermediate hosts (Bulinus spp., n = 3,812; Biomphalaria spp., n = 1,087). Biomphalaria pfeifferi, Biomphalaria sudanica, Bulinus truncatus, and Bulinus forskalii were identified. Biomphalaria species were detected in stagnant or slow-flowing waters; however, they occupied distinct habitats. The presence of snails was found to be independently associated with stagnant water and inversely associated with cassava retting, dishwashing/laundry, and river crossing. These findings provide baseline evidence on the distribution and ecological determinants of the Schistosoma intermediate host in Kimpese, supporting targeted malacological surveillance and integrated control strategies.