[Transmission of Schistosoma haematobium in the town of Niamey, Niger].

Located in an area where Schistosoma haematobium is hyperendemic, the town of Niamey is a focus of hypoendemicity. The aim of the malacological follow-up studies undertaken over a one year period was the determination of the mollusc species present in the water bodies, the appreciation of their space-time distribution of the snail and to find out the potential seasons of transmission. The investigation applied to 22 sites of transmission in the urban community. Four molluscs species (Bulinus truncatus, B. forskalii, B. globosus and B. senegalensis) are collected. The first three species are present all the year long, with a peak of density in the dry season. The last species (B. senegalensis) is found only during the rainy season. B truncatus and B. senegalensis are the two naturally infested species. The main site of transmission is the river Niger. The ponds play a secondary role in the peripheral districts. The main intermediate host of S. haematobium is B. truncatus.