Preliminary study on the resistance conferred on cattle by irradiated metacercariae of Fasciola hepatica in Uruguay

Abstract

An attempt to determine the protective capacity with metacercariae of Fasciola hepatica, attenuated at gamma irradiated level of 3 Krad, was done in cattle through two trials. In trial one with cattle free from F. hepatica, and in trial two with experimentally infected cattle, the irradiated metacercariae dose as well as the experimental infection with non irradiated metacercariae were given orally in gelatin capsuls. The attenuated metacercariae at 3 Krad allowed the host antibody without the total development by most of them in the bile duct. The metacercariae protected 72.5 % those animals in experiment I, and 83.5 % in experiment II. The resistance was reflected in a reduction of the parasite burden as well as in the stabilty of several hematological parameters in the controls. Nevertheless it would be necessary to continue the observations with a larger number of animals.