Cercarial infection in Paludomus petrosus, freshwater snail in Pa La-U Waterfall.

ABSTRACT

Paludomus petrosus, the freshwater snails found in Pa La-U Waterfall, were examined for cercarial infection of trematodes. The snails were collected every other month from April, 2001 to February, 2002. Collections were taken from two sampling stations. The counts per unit of time' method was used for collection of the snails. The density of snails was highest in June 2001, and the highest of parasite infection rate was in February 2002. Four types of cercariae were found in the snails Xiphidiocercariae, Amphistome, Furcocercous cercariae type I, and Furcocercous cercariae type II. Xiphidiocercariae were found in April 2001 to February 2002. Amphistome, Furcocercous cercariae type I and Furcocercous cercariae type II were found in February 2002.