Larval trematode infections in freshwater snails from the highveld and lowveld areas of Zimbabwe

Abstract

AbstractBetween November 1998 and October 2000, freshwater snails were collected monthly from the highveld and lowveld areas of Zimbabwe to determine the occurrence of larval trematodes. A total of 13,789 snails, representing ten species, were collected from 21 sites and 916 (6.6%) harboured patent trematode infections. Eight morphologically distinguishable types of cercariae were identified.Bulinus tropicushad the highest overall prevalence of infection (13.1%). The echinostome was the most common type of cercaria recovered, contributing 38.2% of all infections.Schistosomacercariae were recovered mainly from the highveld and comprised 8.0% of all infections. Amphistome cercariae contributed 37.6% of all infections and were recorded from both the highveld and lowveld areas with a peak prevalence occurring during the post-rainy period (March–May). The main intermediate host for amphistomes wasB. tropicus. Infections inB. globosus,B. forskaliiandBiomphalaria pfeifferiwith amphistome cercariae are new records for Zimbabwe.