Systemic activity of nifluridide against sucking lice and the common scabies mite on cattle.

Psoroptes ovis [Hering] mites and sucking lice (Linognathus vituli Linnaeus) were eliminated from light to heavily infested calves with a single subcutaneous injection of nifluridide in five separate experiments. The compound was incorporated in a copolymer vehicle in a sesame oil suspension. In the first two experiments, mites were eliminated within 10 days following a 20 mg kg-1 injection. Eight out of 9 calves were cleared of mites within 7 days post injection of nifluridide at 4, 6 and 9 mg kg-1 in the third experiment. At the end of the 65 day trial, no live mites were isolated from any of the treated animals. In the last two experiments nifluridide eliminated sucking lice populations at all dosage levels. Complete control of the biting lice (Bovicola bovis) was not obtained. No toxic signs were observed in treated calves.