Infectivity of three species of Fasciola to Wistar rats.

The infectivity of Fasciola spp. to Wistar rats was evaluated with the recovery rate and development of flukes. The recovery rate from the liver parenchyma and bile duct was 20.0-30.0% in F. hepatica, 36.6-47.5% in Japanese Fasciola sp. and 0-5.0% in F. gigantica. Mature flukes were first recovered at week 8 in F. hepatica and week 12 in Japanese Fasciola sp., however, F. gigantica did not mature in the rats examined until 12 weeks after infection. These results suggest that F. hepatica and Japanese Fasciola sp. are high in infectivity to Wistar rats, whereas F. gigantica is low.