Larval trematode infections in freshwater snails from the highveld and lowveld areas of Zimbabwe.
- PubMed: 12498632
Between 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 tropicus had the highest overall prevalence of infection (13.1%). The echinostome was the most common type of cercaria recovered, contributing 38.2% of all infections. Schistosoma cercariae 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 was B. tropicus. Infections in B. globosus, B. forskalii and Biomphalaria pfeifferi with amphistome cercariae are new records for Zimbabwe.