An evaluation of techniques used for the detection of anthelmintic resistance in nematode parasites of domestic livestock.

In vitro and in vivo techniques used for the detection of anthelmintic resistance are reviewed in terms of their versatility, reliability, accuracy, cost and simplicity. The faecal egg count reduction test is considered the most suitable for field screening of resistance but the larval development assay is likely to prove a valuable adjunct in such investigations. Other in vitro techniques, such as egg hatch tests, larval motility and tubulin binding assays are recommended as suitable only for research investigations. Similarly, in vivo procedures such as the critical and controlled anthelmintic efficacy tests are considered to be appropriate only for specific research purposes because of the costs involved in such studies.