Strongyloides sp resistant to albendazole and levamisole in buffaloes from Mexico

Objective. The anthelmintic efficacy of albendazole and levamisole in Strongyloides sp. populations was assessed in buffalo calves (Bubalus bubalis) with natural infections in the Mexican tropic. Materials and methods. 45 buffalo calves were included in the study and distributed into three experimental groups (15 specimens each), according to the excretion of eggs of Strongyloides sp. per gram of faeces (EPG), namely: (a) Control group: without deworming; (b) BZ group (benzimidazoles), which received oral albendazole (10 mg/kg); and (c) IMIDA group (imidazothiazoles) that received levamisole (8 mg/kg) subcutaneously. Faeces were obtained directly from the rectum on days zero (pre-treatment) and 10 (post-treatment) to determine the EPG of each animal. The samples were processed using the McMaster technique. The EPG results were analysed using the RESO software to determine the percentages of egg reduction and their 95% confidence intervals (95% CI). Results. The BZ group exhibited 94% reduction in EPG (95% CI = 87-97), and the IMIDA group exhibited 95% reduction in EPG (95% CI = 84-99). Conclusions. This is the first report in Mexico on the occurrence of Strongyloides sp. populations resistant to benzimidazoles and imidazothiazoles in naturally infected buffaloes from the Mexican tropic.