The Mollusca inhabiting rice fields in northern Cameroon and their role as intermediate hosts for schistosomes

Abstract

A systematic account is given of the freshwater gastropod and bivalve fauna of Ouro-Doukoudje, northern Cameroon, based on a survey conducted from July 2000 to June 2001 at 12 sites in rice fields spanning 800 ha. In total, 14 species were encountered, one of them (Burnupia sp.) being a first record for the area. Thirteen of the species are widely distributed in the Sahelo-Sudanese or Afrotropical regions. Bulinus senegalensis, Bulinus forskalii, Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis occurred throughout the study area and are potential intermediate hosts for schistosomes. Only Biomphalaria pfeifferi was found to be naturally infected with Schistosoma mansoni at nearly all sites in the rice fields. Infection rates were high and varied among sites (21.0–68.6%) and months (14.8–76.6%). Bulinus forskalii was scarce in, and Bulinus truncatus absent from, the study area. Our data are compared with published data for this area as well as for northern Cameroon.