Bithynia siamensis is a species of a freshwater snail with a gill and an operculum, an aquatic prosobranch gastropod mollusk in the family Bithyniidae. Subspecies WHO (1995) recognized the following subspecies: Bithynia siamensis siamensis - synonym: Bithynia siamensis goniomphalus Bithynia siamensis funiculata Bithynia siamensis laevis Bithynia siamensis and Bithynia funiculata (synonym: Bithynia goniomphala) were recognized as separate species in the 2012 IUCN Red List. Distribution This species occurs in: Cambodia Laos Malaysia Myanmar Thailand Vietnam The population of Bithynia siamensis fluctuates during the year. Parasites Bithynia siamensis serves as a first intermediate host for Southeast Asian liver fluke Opisthorchis viverrini. The number of excretory cells of the digestive system is increased in infected Bithynia siamensis. Parasites of Bithynia siamensis include trematode Multicotyle purvisi. References . Further reading External links https://web.archive.org/web/20110723214250/http://www.news.kku.ac.th/eng/news/content/view/134/1/ Bithyniidae Gastropods described in 1856