Species diversity and distribution of schistosome intermediate snail hosts in The Gambia

This study assessed the incidence, species diversity, distribution and infection status of schistosome intermediate snail hosts in the count ry. Malacological surveys were conducted in all 5 regions of The Gambia: Central River Region (CRR), Upper River Region (URR), Western Region (WR), Lower River Region (LRR) and North Bank Region (NBR). Sampling of snails was undertaken at 114 sites that included permanent water bodies such as stream s (bolongs), rice fields, irrigation canals and swamps; and temporal (seasonal) laterite pools. Ecological and physicochemical factors of sites were recorded. Snails were identified morphologically and screened for schistosome infections using molecular techniques. Freshwater snails were found at mo re than 50% (60/114) of sites sampled. While three species ofBulinus were collected, noBiomphalaria snails were found in any of the sites sampled. Of the total 2877Bulinus snails collected, 75.9% were identified asBulinus senegalensis, 20.9% asBulinus forskalii and 3.2% asBulinus truncatus. Seasonal pools produced the largest number of snails, and CRR was the region with the largest number of snails.Bulinus senegalensis was found more in seasonal pools as opposed to permanent sites, whereB.forskalii andB.truncatus were observed to thrive.Bulinus snails were more common in seasonal sites where aquatic vegetation was present. In permanent sites, the abundance of snails increased with increase in water temperature and decrease in water pH.Bulinus sen...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research