CONTROLLED FIELD EFFICACY OF INJECTABLE MOXIDECTIN AGAINST NATURALLY ACQUIRED PSOROPTIC MANGE IN SHEEP

Twenty-one ewes naturally infected with Psoroptes ovis were allocated into three groups of 7 animals each. Animals in group A were kept as u ntreated controls. Animals in groups B and C were treated on day 0 and on day 0 and +10, respectively with 1% injectable moxidectin at a dos e of 0.2 mg/kg body weight (b.w.). In group B, efficacy based on mite count reduction, ranged from 22.1% on day + 7 to 97.1% obtained on day + 56. In group C, this ranged from 19.4% on day +7 to greater than 90 % from days +42 to +56. Active lesions produced by P. ovis remained es sentially unchanged through the trial in the untreated animals. In gro up B, the percentage of efficacy based on reduction of lesions was bet ween 60-90% until day +35 and was higher than 90% at the last three sa mpling dates (+42, +49 and +56). In group C, the reduction of lesions was between 70-90% from days +7 to +21, greater than 97% on days + 28 and +35 and was 100% from days +42 to +56. The high reduction of mites and disappearance (group C) or significant decrease (group B) of clin ical signs make moxidectin effective drug in the control of psoroptic mange in sheep. (C) 1998 Elsevier Science B.V. All rights reserved.