Transmission patterns among freshwater snail hosts of schistosomiasis in Bauchi area of Nigeria

Schistosomiasis is endemic in the Bauchi area of Nigeria but little information is available on transmission patterns on basis of which an effective strategy for control can be developed. Consequently, a longitudinal study on the population dynamics of freshwater snails was under taken in 10 sites selected after a preliminary study. Three schistosome intermediate host snails namely Bulinus globosus, Bulinus truncatus and Biomphalaria pfeifferi all of which carried patent infections were encountered. The population of infected snails showed similar patterns of fluctuation among the different sites. Population density generally increased following the rains and peak densities occurred during the last part of the raining season and/or beginning of the dry season. This was followed by a decline during the dry season owing to an increase in temperature and dessication in some sites. Transmission was observed to be generally focal. In the temporary habitats, transmission was highly seasonal having a short duration of three months spanning from October to December. However, in the few perennial habitats, there was prolonged transmission extending from October of one year to March of the succeeding year. Findings of this study would be invaluable in planning and implementation of schistosomiasis control in Bauchi area, Nigeria.