Distribution of Pila polita in a southern province of Thailand.

This field study investigated the distribution of the freshwater snails of the family Ampullariidae in 18 provinces of Thailand. The introduced Pomacea canaliculata has wide distribution in the studied provinces. Pila angelica, P. ampullacea and P. pesmei still have limited distribution. Pila polita, which is absent in the south, now can be found in Phangnga, a southern province of Thailand. Moreover, P. polita is currently used as a traditional medicine of the local people for the treatment of a skin disease.

Survival of beta and gamma races of Neotricula aperta snail intermediate hosts of Schistosoma mekongi in raw waters.

Beta and gamma races of Neotricula aperta were exposed to naturally raw waters of the Sirindhorn reservoir, Mun River and Mekong River in laboratory conditions and non supplement on food. Snails of two races could withstand well in variable qualities of water within 48 hours. The survival rates of N. aperta in three sources of raw water were 100% for the beta race and 97 to 100% for the gamma race.