Digenetic Parasites Transmitted from Freshwater Snails to Other Hosts : Morphobilogical studies

During the period from May 2002 to April 2003, a number of 14075 freshwater snails were examined to investigate the cercarial infection rate, seasonality and description of it. A number of 277 (1.927%) snail were found to be infected. The infection rate between different freshwater snails was high in Lymnaea cailliaudi (8.208%), followed by Bulinus truncatus (5.500%), then Melania tuberculata (5%), Lanistes carinatus (3.511%), Cleopatra bulimoides (1.078%) and the lowest in Biomophilaria alexanderina (0.963%). Two snail species were found free from any infection during the period of the study, Physa acuta and Vivipara unicolor. In the present study, the obtained cercariae were classified into: 2 Amphistome cercariae, 2 Parapleurolophocercous cercaria, 3 Gymnocephalus cercariae, 1 Distome cercaria, 2 Echinostome cercariae, 8 Furcocercous cercariae and 10 Xiphidiocercariae. Twelve species of cercariae were found infecting Cleopatra bulimoides, which are Megalodiscus sp. cercaria, Parapleurolophocercous cercaria, Philophthalmus sp. cercaria, Centrocestus cercaria, Distome cercaria, Cercaria vivax, Cardicola cercaria, and 5 species of Xiphidiocercariae