Situation and Cercarial Infection of Freshwater Mollusk from Sirindhorn Reservoir, Ubon Ratchathani Province, Thailand.

Background: Most of trematodes need snails to complete their life cycles. Consequently freshwater snails are served as intermediate hosts of many parasites worldwide. There is a lack of report on snail diversity and parasitic infection in snails in Sirindhorn Reservoir, Ubon Ratchathani province, Thailand.

Methods: Mollusk diversity and trematode cercariae infections were investigated in snails from 120 sampling sites surround Sirindhorn Reservoir from April 2018 to June 2018. Mollusk species were identified based on their shell morphology. The presence of cercariae infections in snails was examined by cercarial shedding methods. The interaction between snail species was analyzed by the correlation method.

Results: Overall, 2076 mollusks were collected which comprised six species of snails and two species of bivalves. Snail species were identified as Bithynia siamensis goniomphalos, Anentome helena, Filopaludina sumatrensis spiciosa , F. martensi martensi, F. martensi munensis and Pomacea canaliculata. The overall rate of trematode cercariae infection was 1.69% (35/2,076). The cercariae found infecting snails were Cercariaeum cercaria, Virgulate cercaria, Cotylomicrocercous cercaria and Furcocercous cercaria. The most common snails found was the assassin snail, A. helena, which showed the negative relationship among other species interactions.

Conclusion: This finding indicated infection with animal's parasites in snails in this area are common, besides, we found many species of snails in Sirindhorn Reservoir are potentially be the host of parasite in animal and human.