Assessment of Anthelmintic Resistance in Major Gastrointestinal Nematodes in Sheep and Goat Farms in Mymensingh, Bangladesh.

Anthelmintic resistance (AR) is a well concern in livestock production. Hence, the study was designed to assess the status of AR in sheep and goat farms at Mymensingh sadar using fecal egg count reduction test (FECRT) and egg hatch assay (EHA). To do this, 10 farms were selected. For FECRT, 40 animals of each farm having more than 200 EPG of feces were selected randomly by employing the McMaster technique and treated with albendazole (ABZ), levamisole (LEV), and ivermectin (IVM). Fecal samples from animals of each treated and control group were collected directly from the rectum on Day 0 (pretreatment) and Day 14th posttreatment (p.t.), pooled, and considered for coproculture to detect resistant parasites. For EHA, pooled fecal samples were collected from each farm and isolated eggs by combining flotation and sedimentation techniques. The isolated eggs were treated with different concentrations of ABZ solution, such as 0.05, 0.1, 0.2, 0.3, and 0.5 μg/mL, by maintaining a control group with no ABZ solution. The result revealed that in FECRT, ABZ resistance against gastrointestinal (GI) nematodes was detected in nine farms and suspected resistance in one farm. LEV resistance was detected in six farms and suspected resistance in four farms. Interestingly, IVM resistance was developed in one farm, suspected resistance in five farms, and susceptible against GI nematodes in four farms. Also, Haemonchus and Oesophagostomum were recognized as resistant parasites using coproculture. In EHA, ABZ resistance was also detected in all farms. The EC50 value of ABZ ranged from 0.1290 to 0.2393 μg ABZ/mL (> 0.1 μg/mL) with the coefficient of correlation (R 2) > 0.98. The present study suggests that AR is increasing and creates an upsetting situation in controlling GI nematodes in Bangladesh. Therefore, the use of alternative control methods such as ethnomedicine, bioactive forages, and selective treatment procedure should be practiced.