EFFICACY OF A NOVEL LONG ACTING IVERMECTIN AGAINST SARCOPTIC MANGE IN PIGS SUBMITTED TO A HIGH NATURAL CHALLENGE

摘要

Long Acting (LA) formula exhibits an added value compared to other injectable formula, since it maintains efficacious plasma levels of Ivermectin for longer time, providing protection against mite eclosion well after eggs incubation period. The present study was aimed to evaluate the immediate and long term efficacy of a single intramuscular (IM) injection in the neck of long acting Ivermectin (VIRBAMEC~(R) LA) compared to Doramectin (DECTOMAX~(R)) in the control of chronic mange in gilts. Twenty onenaturally infested pigs from an industrial pig farm (1880 sows) with a mange history were selected on the basis of live mite counts of skin scrapings performed before the trial, on D-7. Animals were ranked according to their live mite counts and allocated at random into three groups (n = 7). At DO, pigs in Group A were treated intramuscularly with LA Ivermectin (300 mu g/Kg BW = lmV33Kg), pigs in Group B were injected intramuscularly with Doramectin (300 mu g/Kg BW = lml/33Kg) while saline solution wasgiven to control animals in Group C (lml/33Kg BW). The three groups were housed together in the same or different pens without solid walls in between. Nothing was attempted to avoid cross-contamination between groups, and treated animals were continuously challenged by mites from untreated pigs or direct environment. Skin scrapings were performed on DO before treatment and D7, D14, D21, D28, D35, D42 and D49 post-treatment in which eggs, live and dead mites (larvae, nymphs and adults) were counted andrecorded. Percentage of efficacy was calculated at each observation day using the Abbott's formula. A clinical score based on lesion (0 to 3) and pruritus (0 to 3) scores was calculated at each inspection time. Statistical analyses (two-way ANOVA) were performed on the transformed data Log (Mite Count + 1) followed by Bonferroni Multiple Comparison Test at the significant level of P < 0.05.