THE PROSPECT OF VACCINATION WITH GAMMA-IRRADIATED METACERCARIAE AGAINST FASCIOLA-GIGANTICA INFECTION IN GOATS

Vaccination of goats with a single dose of 250 gamma-irradiated Fasciola gigantica metacercariae resulted in partial resistence to subsequent homologous challenge after four weeks with the same number of viable cysts. The resistence was manifested, mainly, by severe reduction in the size of the flukes though their numbers were comparable to those recovered from primarily infected (non-vaccinated) goats. The hepatobiliary lesions and sequential changes in the plasma enzyme activity were considerably ameliorated in vaccinated goats. In addition, vaccination with gamma-irradiated metacercariae was also associated with a higher antibody response to F. gigantica infection.