Development and validation of an in vitro Trichostrongylus colubriformis motility assay

Development and validation of an in vitro Trichostrongylus colubriformis motility assay. International Journal for Parasitology 17: 1441–1444. An in vitro Trichostrongylus colubriformis motility assay involving the use of a micromotility meter has been developed and validated. Four commercially available ruminant anthelmintics (albendazole, ivermectin, levamisole hydrochloride, and coumaphos) and an investigational hydrazone compound ( p-toluoyl chloride phenylhydrazone) were evaluated in this assay at four concentrations each. At 100 μg ml -1, all five treatments significantly ( P ⩽ 0.05) reduced the motility of ensheathed L-3 T. colubriformis larvae, thereby indicating anthelmintic activity. At this concentration, coumaphos was significantly less active than any of the other four treatments. At 10 μg ml -1 albendazole, ivermectin, levamisole hydrochloride and the hydrazone compound were active, but coumaphos was not. At 1 μg ml -1 albendazole, ivermectin and levamisole hydrochloride remained significantly active, but neither coumaphos nor the hydrazone compound showed significant activity. At all three of the higher concentrations (1,10 and 100 μg ml -1), levamisole hydrochloride indicated greater activity than any of the other treatments. This difference was statistically significant at the 1 and 10 μg ml -1 concentrations. None of the five treatments showed significant activity at the lowest concentration (0.1 μg ml -1). The in vitro T. colubriformis motility assay proved to be sensitive, accurate, rapid, and repeatable. This assay system should be another valuable addition to the tests used to identify potential anthelmintics, monitor helminth resistance to drugs, and define the kinetics and mode of action of drugs.