Seasonal changes in the distribution and infection rate of schistosome intermediate hosts in river Kubanni and its tributaries

Abstract

A 12-months snail sampling using the man/time method was carried out in river Kibanni and its tributaries in order to determine the seasonal abundance and infection of schistosome vectors within the AhmaduBelloUniversitycommunity.  Two genera of snails Bimphalaria and Bulinus were recovered.  With the exception of Bulinus recovered from the temporary flowing tributary all others were capable of carrying cercariae of human schistosome.  Of the 4119 schistosome vectors collected, 204 (5%) were carrying schistosome infection.  Bulinus (0.6%) and Biomphlaria (7.8%).  Both snail density and infection were profoundly influenced by rainfall with both indices reaching their peak in dry season (November – April).  Transmission of Schistosoma mansoni by Biomphlaria pfeifferi was not only exceptionally higher than S. haematobiu by Bulinus in the permanent flowing habitat, but was the sole schistosome transmitted in the temporary flowing tributary (ibfection rate: 8.8% vs 2.3% and 7.4% vs 0.0%).  This study demonstrate therefore, the seasonal occurrence and infection of schistosome intermediate host and the high transmission of especially schistosomiasis mansoni.