ECOLOGY OF SCHISTOSOMA SNAIL VECTORS IN ADO-EKITI LOCAL GOVERNMENT AREA, EKITI STATE, NIGERIA

A study on the ecology of snail hosts of Schistosoma was carried out in River Ogbesse and River Ureje in Ado - Ekiti Local Government Area, Ekiti State Nigeria between February 2009 and January 2010. Fourteen sampling stations were selected for the study. Stations 1-7 were located on River Ureje while Stations 8-14 were located on River Ogbesse. Each station was randomly sampled fortnightly every month for snail taxa composition, physico - chemical characteristics of water and vegetation cover. The data were analyzed using non-parametric statistical methods. A total of 2559 snails belonging to six species, five genera, three families and two subclasses were recorded in the two rivers. These were 446 (17.4%) specimens of Bulinus globosus, 122 (4.8%) B. truncatus, 264 (10.3%) Potadoma freethi, 1628 (63.6%) Melanoides tuberculata, 58 (2.3%) Lanistes varicus and 16 (0.6%) Biomphalaria pfeifferi. Two of the six snail species (B. globosus and Biomphalaria pfeifferi), which are established intermediate hosts of schistosomiasis were recovered from River Ureje only. Furcocercous cercaria was recovered from Bulinus globosus species. The relationship between snail vectors and aquatic macrophytes is discussed.