Detection of activity for various anthelmintics against in vitro-produced Cooperia punctata

The in vitro-grown parasitic stages of Cooperia punctata were used to evaluate 28 compounds with different kinds and degrees of in vivo activity. Using presumptive and confirmatory tests, it was possible to establish a group order of in vitro potency that compared favorably with an order based on established in vivo use of these compounds. The procedure lends itself to evaluating activity against a given parasitic growth stage and gives a quantitative estimate (range) of the concentration that produces 50% nematode kill. The system was most successful in detecting compounds with in vivo activity for C punctata, followed in order by compounds active against Cooperia spp, other gastrointestinal nematodes of ruminants, and other nematodes of non-bovine hosts. The procedure showed some differentiation between activity against nematodes versus that against cestodes, trematodes, and arthropods. The system permits considerable flexibility in experimental design, thus making possible the acquisition of the particular information desired. In addition to establishing lethal effects on the nematode, the procedure detected compounds with nematode-anesthetizing effects. The results indicate this in vitro system can be used with some expediency as a preliminary screening method in the search for new anthelmintic compounds.