[Effectiveness of moxidectin (Cydectin inj.) in mixed Psoroptes ovis and Sarcoptes ovis infestations in sheep].

Field efficacy of moxidectin injectable was evaluated in sheep naturally infected with both Psoroptes ovis and Sarcoptes ovis mange. Three groups of fifteen ewes were selected from the flock based on parasitological and clinical status. Group 1 remained as untreated controls. Group 2 animals received a subcutaneous injection of moxidectin at 0.2 mg/kg body weight on Day 0; Group 3 animals received 0.2 mg/kg moxidectin twice on Day 0 and Day 7. Efficacy was assessed by taking skin scrapings from each animal on Days -4, 0, 7, 14, 28 and 35 post treatment (P.T.) and counting viable mite stages and species. In both treated groups the signs of itching disappeared within seven days P.T. Rapid clinical improvement was associated with reduction in numbers of mites compared with initial score which was over 90%. However, in skin scrapings on Day 7 P.T. several live mites of both species were present. The second injection of moxidectin removed all living mites and skin scrapings from group 3 animals that were negative for all mites on days 14, 28 and 35. The weight gain on average in group 2 was 2.0 kg and in group 3 2.7 kg, during the 35 days of trial. Untreated control animals have lost on average 3.1 kg from the weight at start of trial. All untreated animals remained positive and suffered from intensive scratching, anorexia and moist active skin lesions. Therefore they were given an emergency moxidectin treatment on days 35 and 37 each animal receiving 0.2 mg/kg b.w., subcutaneously. Moxidectin in both tested doses was well tolerated and no local reaction on injection sites was observed.