RESUMO
The study was conducted at 75 collecting loci in 15 districts of 11 provinces in Thailand during 1999-2004. A total of 12,079 live mollusks were collected, 11,874 were snails and 205 were clams. The snails were comprised of 39 species and classified into 9 families: Ampullariidae, Bithyniidae, Buccinidae, Potamiopsidae, Stenothyridae, Thiaridae, Viviparidae, Planorbidae and Lymnaeidae. The clams were comprised of 14 species classified into 2 families: Amblemidae and Corbiculidae. Fifteen species were medically important snails: Pomacea canaliculata, Pila ampullacea, P. pesmei, P. polita, Bithynia (Digoniostoma) funiculata, B. (D.) siamensis goniomphalos, B. (D.) s. siamensis, Filopaludina (Siamopaludina) martensi martensi, F. (Filopaludina) sumatrensis polygramma, Melanoides tuberculata, Tarebia granifera, Helicorbis umbilicalis, Gyraulus convexiusculus, Indoplanorbis exustus and Radix rubiginosa. Of these 3 snail species harbored trematode cercariae. I. exustus harbored Echinostoma malayanum, Xiphidio and Schistosoma spindale, and R. rubiginosa and B. (D.) siamensis goniomphalos harbored Xiphidio and intestinal flukes, respectively.