Evaluation of the Clinical Efficacy and Safety of a Spot-on Combination of Imidacloprid 10 % / Moxidectin 2.5 % (Advocate®, Advantage® Multi) in Comparison to an Untreated Control Group in the Treatment of Capillaria boehmi in Naturally Infected Dogs

Capillaria boehmi affects the upper respiratory tract of domestic and wild canids. The aim of the present study was to investigate the efficacy of imidacloprid 10%/moxidectin 2.5% spot-on (Advocate®, Advantage® Multi, Bayer) in dogs naturally infected by C. boehmi. Twenty dogs infected with C. boehmi were randomly allocated to two groups: T1 (10 dogs) received a single treatment of Advocate® using the recommended dose on day 0 and T2 (10 dogs) served as an untreated control group. The reduction of the faecal egg counts (EPG) from baseline (days -6±2 and -2±2) to study completion was set as the primary efficacy criterion; clinical assessments of the upper respiratory tract and a rhinoscopy to visualize the parasites were used as secondary efficacy criteria. Eight dogs in T1 were not shedding eggs on days 28±2 (reduction of EPG 99.66 %). A second treatment was administered to two dogs still positive on days 30±3. A second efficacy evaluation was performed on days 42±2 (study completion), when the two dogs tested negative. The mean number of EPG at study completion was 0 in T1 and 368.49 in T2. The difference between the groups was statistically significant (P<0.01). Treatment efficacy at study completion was 100 %. None of the T1 dogs showing clinical signs on day 0 were symptomatic on days 28±2. No adverse events occurred. The results show that Advocate® is safe and effective in the treatment of canine nasal capillariosis.