Ecological studies on the snail hosts of schistosomiasis in the South Chad Irrigation Project Area, Borno State, northern Nigeria

Abstract

Qualitative and quantitative samples of aquatic snails were collected over a two year period in the South Chad Irrigation Project Area, northern Nigeria. The area and its climate are described. Lake Chad, the irrigation channels and temporary pools are defined as three major categories of snail habitat and an account of the seasonal abundance of their snail populations is given. Bulinus rohlfsi, Bulinus forskali, a form of Bulinus globosus and Biomphalaria sudanica occurred in Lake Chad. Bulinus rohlfsi, Bulinus forskali, Bulinus senegalensis and another form of Bulinus globosus were found in irrigation channels. Bulinus senegalensis was the only bulinid recovered from temporary pools. The seasonal patterns of the snails are considered in relation to climatic and habitat changes. The possible roles of the bulinids in Schistosoma haematobium transmission are discussed.