Susceptibility to homologous reinfection with Fasciola gigantica in goats.

Goats previously infected with 100 viable Fasciola gigantica metacercariae and treated with rafoxanide (Ranide, 7.5 mg/kg) at week 4 were not protected against subsequent homologous challenge with 250 metacercariae administered two weeks later. Reinfection resulted in more severe hepatic lesions and a higher percentage of flukes recovered as compared with primarily infected controls. However, the size of flukes originating from the second (challenge) infection was considerably reduced. The plasma enzyme activity of aspartate amino-transferase (AST), glutamate dehydrogenase (GD) and sorbitol dehydrogenase (SD) increased to a similar extent with primary and challenge infections. However, the plasma antibody response to F. gigantica was less pronounced in reinfected goats.