PREVALENCE AND INCIDENCE OF CERCARIAL INFECTION IN FRESHWATER SNAILS IN KANNUR DISTRICT (KERALA)

An attempt to survey trematode infection in snails was carried out during the period January - October 2008 in Kannur district. During the explorative study a total of 671 snails were collected which include4 three pulmonate snails - a Iymnaeid Lymnca luteola, two planorbids Gyraulus convexiusCUlUS and IndoplanorbiS exustus - and four prosobranch snail, Bellamya bengalensis, Thiara tuberculata, Paludomous transchauriCUS and Pila virens. The infection rate and the larval forms released were monitored. The cercariae released belonged to the groups the Amphistome, EchinostOme, Furcocercous and XiphidiocercoUs. Most of the cercana1 infections were recorded from Indoplanorbis exu’° ‘1 - .3%), which harboured all the four morphologicallY different cercariae. No infections were recovered from PaludomouS transchauriCUS and Pila virens.