TRICLABENDAZOLE TREATMENT IN EXPERIMENTAL GOAT FASCIOLIASIS - ANTHELMINTIC EFFICACY AND INFLUENCE IN ANTIBODY-RESPONSE AND PATHOPHYSIOLOGY OF THE DISEASE

A controlled test of the efficacy of triclabendazole against all stage s (early immature, late immature and mature) of Fasciola hepatica has been performed in experimentally infected goats. The influence of tric labendazole treatment on the pathophysiology of the disease, in terms of haematological parameters and serum enzyme levels, and in the dynam ics of production of specific antibodies to excretory/secretory produc ts (ESP) of F. hepatica were also examined. Goats were orally infected with 200 viable metacercarie and treated at 4, 8 and 16 weeks postinf ection (PI) with triclabendazole at the dose rate of 10 mg kg(-1) body weight. The drug can be regarded as highly effective against mature ( 100%) and late immature (99.2%) flukes and effective against early imm ature flukes (94.9%). A moderate anaemia was found associated with the presence of late immature and mature flukes in bile ducts. Treatment with triclabendazole, by eliminating most of these flukes, largely red uced haematological alterations. Serum levels of the enzymes aspartate aminotransferase, lactate dehydrogenase and gamma-glutathione transfe rase reflected hepatic damage during goat fasciolosis. Early treatment (at 4 weeks PI) prevents the development of both parenchyma and bile ducts lesions; treatment at 8 weeks PI only prevents bile ducts lesion s and treatment at 16 weeks PI has no appreciable effect on the develo pment of the main hepatic lesions. The antibody response to F. hepatic a ESP, as measured by enzyme-linked immunosorbent assay, was also affe cted by treatment with triclabendazole. In all treated animals a peak in antibody levels was observed between weeks 9 and 13, followed by a drop whose magnitude depended on the efficacy of treatment. In those a nimals in which triclabendazole was highly effective, antibody levels fell back to negative values similar to those recorded preinoculation at 18-21 weeks PI.