FASCIOLA-HEPATICA LINNAEUS - THE REDIAL B URDEN AND CERCARIAL SHEDDING IN THE JUVENILE LYMNAEA-PEREGRA PEREGRA MULLER

Experimental infections of Lymnaea peregra peregra by Fasciola hepatic a were carried out to determine the ability of this subspecies to insu re the trematode larval development. Infection rate was 38 % in the ne wborns and 9.5 % in the juvenile snails measuring 1 mm in height at mi racidial exposure. At day 30 the total number of rediae was 7 in avera ge in the former group (including 4.2 cercaria-containing forms) and 1 5 in the latter group (7 rediae with cercariae). The mean duration of the patent period was 5 days, and cercariae were often shed during a s ingle shedding wave. The mean number of metacercariae was 22.2 in the former group and 36.5 in the latter group. All these findings suggest that this subspecies of L. peregra is only an accidental intermediate host in the life cycle of F. hepatica.