Genetic markers for studies on the systematics and population genetics of snails, Bithynia spp., the first intermediate hosts of Opisthorchis viverrini in Thailand

► Multilocus enzyme electrophoresis was used to genetically analyse Bithynia snails. ► They are the critical amplifying hosts of the liver fluke Opisthorchis viverrini. ► Twenty four enzyme loci were established as genetic markers for three Bithynia taxa. ► Fixed genetic differences between taxa were detected at 67-73% of loci examined. ► Genetic difference levels question validity of current traditionally defined taxa.