Spot-on treatment with moxidectin and imidacloprid for dog demodicosis

Abstract

In this multicentre study, the efficacy of a spot-on formulation containing 10% imidacloprid and 2.5% moxidectin (Advocate, Bayer HealthCare) was evaluated for the treatment of dogs with generalized demodicosis. The spot-on was applied every 2 weeks. Secondary bacterial infections were diagnosed by clinical examination, cytology and bacterial culture as appropriate and treated with oral antibiotics. Improvement or deterioration was determined monthly by clinical scores and by assessing mite numbers on microscopy of skin scrapings. Seventy-two dogs were included in the study. Fifty-two dogs had juvenile-onset demodicosis (mean of 11 months, range 2-24 months) and 20 dogs were adults at onset of disease (mean of 8.6 years, range 3.5-14 years). Twenty-six dogs went into remission, three with adult-onset demodicosis, 23 with juvenile-onset. The latter group showed significantly higher remission rates (P = 0.0252). Time until remission varied from 4 to 32 weeks (mean of 12.5 weeks). Dogs with a clinical score of <45 at the beginning of the study showed a significantly better response to the treatment (P = 0.0004), with a remission rate of 71%. In contrast, only 24% of those dogs with a score >45 went into remission. Adverse effects were not observed. One of the dogs responding to treatment showed recurrence of the disease during a follow-up period of 12 months. This study shows a better success rate of Advocate in dogs with mild clinical signs, versus those with moderate to severe clinical signs.