experimental life cycle of hypoderaeum conoideum (block, 1872) diez, 1909(trematoda: echinostomatidae) parasite from the north of iran

background: human echinostomiasis is an intestinal disease caused by the members of family echinostomatidae parasites. the aim of present research was to identify echinos­tomatidae cercariae emitted by lymnaea palustris snails from mazandaran province in the north of iran based on the morphological and morphometrical charac­teristics of the different stages of experimental parasite life cycle. methods: echinostomatidae cercariae were collected from l. palustris (gastropoda: lymnaeidae) of the north of iran. to collect metacercaria, 50 healthy snails were infected with cercariae experimentally (50 cercariae for each). to obtain the adult stage, 9 laboratory animals (3 ducks, 2 rats, 2 mice and 2 quails) were fed with 60 metacercaria for each. to identify parasite, the different stages of worm were exam­ined using light microscope and then the figures were draw under camera lucida microscope and measures were determined. results: averagely, 15metacercaria were obtained from each snail that had been previously exposed with cercariae. ducks presented worm eggs in feces after 10-15 days post-infection. intestinal worms were collected and identified as hypoderaeum conoideum on the bases of figures and measures of cephalic collar, the number of collar spine, suckers diameter ratio, testes arrangement, etc. conclusion : h. conoideum cercariae and adult worm are described . this is the first report of the different stages of the experimental life cycle of this parasite in iran.