EFFECTS OF LUXABENDAZOLE ON THE TEGUMENT OF FASCIOLA-HEPATICA

The effects in vivo of 5, 10, and 20 mg/kg of luxabendazole (LBZ) on t he tegument of Fasciola hepatica have been examined 48 h, 7 days and 1 4 days post-treatment of experimentally-infected rats. As early as 48 h post-treatment, the drug is shown to provoke significant damage to t he tegument. The pathological phenomena characterizing LBZ damage are blebbing of the apical plasmalemma, formation of microvillus-like proj ections over the free surface, swelling of the basal infolds and stimu lation of autophagy. The spines are often fractured; the tegument in t he vicinity of spines seems more strongly altered than that in other f oci. The basal layer is often changed, from increase of electron densi ty to lack of integrity with the apical cytoplasm. The progress of the ultrastructural damage with time is not expressed. However, cytochemi cal data show that at longer post-treatment intervals the surface-coat structure becomes irregular and patches of ruthenium red positive mat erial of variable thickness are focally accumulated. Only a slight dos e-effect is noted 48 h after LBZ application when the alterations prov oked by 5 mg/kg are less evident than those by 10 and 20 mg/kg.