Role of environmental parameters on the density of intermediate host snails of human schistosoma during the year in the commune of Richard-Toll, Senegal.

The implementation and expansion of development projects (dams and irrigation schemes) in the Senegal River valley have led to a significant proliferation of snails. We conducted a one-year (2014) study project, monitoring their density in the commune of Richard Toll, to assess the role of environmental parameters on mollusc population dynamics. Four species involved in the transmission of human schistosomiasis were found: Bulinus globosus, B. truncatus, B. senegalensis, and Biomphalaria pfeifferi. Among the intermediate hosts, B. truncatus is the most abundant species, followed by B. globosus. Snail density depends on the nature of the water point but also on environmental parameters such as vegetation. This study showed that vegetation, water level (flood), and flow velocity influence the dynamics of the snail populations that are intermediate hosts of human schistosomes.