2 November 2001

Irish report sheep scab drug findings

RESEARCH into the persistence of three sheep scab injectables demonstrates the importance of appropriate pasture management after treatment to avoid reinfection.

Published in the Vet Record, the trial was carried out by Dermot OBrien of Dublins Central Vet Research Lab. In the trial, sheep were treated with doramectin, moxidectin or ivermectin before being challenged with scab mites.

"The results of this study confirm those of previous studies showing moxidectin has persistent activity against scab mites for at least 28 days.

In contrast, ivermectin and doramectin did not provide protection against reinfection for the 17-day period during which scab mites can survive off sheep," says Dr OBrien.

"Where scab mites are present, sheep injected with moxidectin may be safely reintroduced to the infected area. But when ivermectin or doramectin are used, animals should be moved to clean pasture to avoid reinfection from the environment." &#42