Fasciola hepatica development in the experimentally infected black rat Rattus rattus.

The finding of natural infection of Rattus rattus by Fasciola hepatica on Corsica has stimulated further research into the role of the black rat in the epidemiology of fascioliasis. Corsican black rats were experimentally individually infected with 20 metacercariae from cattle and murine isolates obtained from naturally infected bovines and black rats. The following results were obtained: (a) in R. rattus infected with the cattle isolate, normal adult fluke development took place and infection persisted for a long period, with emission of eggs showing embryogenic capacity; (b) the development of F. hepatica adults paralleled the ontogenetic trajectories observed in other rodent-F. hepatica models; and (c) fluke adults obtained in R. rattus infected with the murine isolate exhibited a similar pattern. These findings strongly suggest that the black rat may be one of the wild reservoirs of F. hepatica and may have contributed to the large geographical extent of the disease on Corsica.