EFFICACY OF INJECTABLE MOXIDECTIN AGAINST MIXED (PSOROPTES OVIS AND SARCOPTES-SCABIEI VAR OVIS) MANGE INFESTATION IN SHEEP

Field efficacy of injectable moxidectin was evaluated in sheep natural ly infested with both Psoroptes ovis and Sarcoptes scabiei var. ovis m ange. Three groups of 15 ewes were selected from the flock based on pa rasitological and clinical status. Group 1 remained as untreated contr ols; Group 2 animals received a subcutaneous injection of moxidectin a t 0.2 mg kg(-1) body weight on Day 1; Group 3 animals received 0.2 mg kg(-1) moxidectin twice on Day 1 and Day 7. Efficacy was assessed by t aking skin scrapings from each animal on Days -4, 0, 7, 14, 28 and 35 post-treatment and counting viable mite stages and species. In both tr eated groups the signs of itching disappeared within 7 days post-treat ment. Rapid clinical improvement was associated with reduction in numb ers of mites compared with initial score which was over 90%. However, in skin scrapings on Day 7 post-treatment several live mites of both s pecies were present. The second injection of moxidectin removed all li ving mites, and skin scrapings from Group 3 animals were negative for all mites on Days 14, 28 and 35. The weight gain an average was 2.0 kg in Group 2 and 2.7 kg in Group 3 during the 35 days of trial. Untreat ed control animals lost on average 3.1 kg from their weight at the sta rt of the trial. All untreated animals remained positive and suffered from intensive scratching, anorexia and moist, active skin lesions. Th ey were given an emergency moxidectin treatment on Days 35 and 42, eac h animal receiving 0.2 mg kg(-1) body weight, subcutaneously. Moxidect in in both tested doses was well tolerated and no local reaction at in jection sites was observed.