Our objective was to determine by scanning electron microscopy the structural changes in the tegument of adult Fasciola hepatica after treatment with 5-chloro-2-methylthio-6-(1-naphtyloxy)-1 H-benzimidazole, called compound alpha, and its active metabolite sulphoxide, under in vitro and in vivo conditions. For the in vitro studies, flukes from sheep were exposed to 40 mg/l of compound alpha-sulphoxide over different incubation times. Flukes for the in vivo studies were raised in sheep treated orally with compound alpha and killed at different times post-treatment. Non-treated controls were included for each time of incubation. The results showed lesions after 6 h of treatment, such as swelling and furrows. At 12 h, the spines appeared to be surrounded by the tegument. At 24 h the tegument in some areas showed an exposed basal lamina. These changes became more severe as the incubation periods of the treated flukes increased. Compound alpha exerts a significant effect on the tegument of F. hepatica.
Copyright 2004 Springer-Verlag