Anthelmintic resistance of gastro-intestinal nematodes to albendazole, levamisole and ivermectin in Murrah buffaloes

Abstract

Resistance in buffaloes to anthelmintic treatment has already been reported. However, there is paucity of information about anthelmintic resistance in Murrah buffaloes in the Philippines. In the present study, 36 Murrah buffaloes (24 aged >1 to 2 years and 12 aged >2 to 3 years) naturally-infected with gastrointestinal nematodes were observed to determine the efficacy of albendazole (ABZ), levamisole (LEV) and ivermectin (IVM). The efficacy of the drugs was determined through the fecal egg count reduction test (FECRT). The presence of anthelmintic resistance was confirmed if the fecal egg count reduction (FECR) is lower than 95% and if the lower limit of the 95% confidence interval is lower than 90%. Resistance to the anthelmintics albendazole and levamisole was exhibited by gastro-intestinal nematodes infecting Murrah buffaloes in this study. On the other hand, Ivermectin still showed efficacy against gastrointestinal nematodes but only in buffaloes less than two years old. Resistance to ivermectin was already demonstrated in buffaloes >2 to 3 years of age. The observed resistance in albendazole and levamisole may be explained by the regular use of these two drugs in the farm’s parasite control program. The study suggests that better strategies may be considered by the farm for a more sustainable control against helminthiasis.