Sensitivity of Isolates of Eimeria from Turkey Flocks to the Anticoccidial Drugs Amprolium, Clopidol, Diclazuril, and Monensin

The sensitivity of field isolates of turkey coccidia from the United States to the anticoccidial drugs amprolium, clopidol, diclazuril, and monensin was investigated. Clopidol and diclazuril were the most effective, followed by monensin and amprolium. Thirty-one isolates were classified as resistant to amprolium, 23 resistant to monensin, 10 resistant to diclazuril, and 6 resistant to clopidol. Six isolates were partially resistant to monensin, 10 partially resistant to clopidol, and 11 partially resistant to diclazuril. Four isolates were sensitive to monensin, 12 sensitive to diclazuril, and 17 sensitive to clopidol.