Abstract
The snail host of Fasciola sp. was experimentally defined to be Lymnaea truncatula in the Tempoku district of Hokkaido. This species of snails from the district was exposed to miracidia of liver flukes from the same district. Sporocysts recovered on day 4 after exposure were 107.1-203.1×44.8-97.6μm, and rediae were 302.9-306.8×38.5-86.8μm on day 9 and 363.0-1, 550.9×82.5-265.5μm on days 24 to 28. Rediae contained 1 to 5 cercariae. The duration from the exposure of snails to miracidia to cercarial shedding was 45 days at a water temperature of 21°C to 31°C and 38 days at 28°C. Metacercariae were 196.9-307.3×192.6-213.4μm in size. The prepatent period was 64 to 71 days in goats and worm recovery was 70.0% and 22.2% on days 133 and 172 after infection, respectively. L. auricularia from the district showed total resistance to the infection with the liver fluke.
