Prevalence, infestation dynamics and assessment of ivermectin systemic scab treatment efficiency in sheep of north - eastern Algeria

Abstract A cross-sectional study, carried out between August 2015 and May 2016, in order, first to assess the prevalence and the seasonal sheep mange dynamics, and second to test the efficacy of ivermectin sarcoptic mange treatment. 11759 animals from 1072 flocks and livestock markets in Guelma, a north-eastern Algerian province, were followed up. The results showed that the infestation mean prevalence of flocks and animals was 25 and 10.45% respectively. Two major species of mange mites were identified: Sarcoptes scabiei var.ovis and Psoroptes ovis. These latter accounted respectively for 70 and 30% at flock level and 68 and 32% at individual level. A highly significant level probability was noted between the two species (P <0.001). None of these species was seen during summer and spring. However, during winter and autumn, 55 and 45% of flocks were respectively infested and the prevalence of the infested sheep recorded was 25.1% in winter and 15.52% in autumn. The results from the livestock markets supported those of the cross-sectional study. The ivermectin treatment via a single injection at a 0.3 mg/kg doses per bodyweight was efficient in severely sarcoptic mange affected flocks. Two injections are, however, recommended in animals with very marked hyperkeratosis. The present study proved a high overall and seasonal occurrence of mange mites in sheep living under Mediterranean climatic conditions. Animal breeders and veterinarians should jointly implement effective treatment strategies based on a single or a double injection at 0.3 mg/kg according to the severity of mange infestation (presence or absence of hyperkeratosis) so as to avoid economic losses inherent to this pathology. Key words: sheep scab, prevalence, Guelma – Algeria, ivermectin, efficiency