Evaluation of the anti-feeding and insecticidal effects of a topically administered combination of imidacloprid and permethrin (Advantix®) against Phlebotomus (Larroussius) perniciosus (Newstead, 1911) in dogs following monthly administration.

Abstract

BACKGROUND: Two laboratory experiments (Studies 1 and 2) were conducted to confirm the efficacy of an imidacloprid and permethrin combination (Advantix&#xae; Spot-on, Bayer) to repel and kill Phlebotomus (Larroussius) perniciosus sand flies when applied once a month topically to dogs. METHODS: Both studies compared dogs treated with a combination containing 100&#xa0;mg/ml imidacloprid +&#x2009;500&#xa0;mg/ml permethrin (Advantix&#xae; Spot-on, Bayer) to placebo treated dogs. The treatments were applied topically on Day -28 (Study 2) and Day 0 (Studies 1 and 2). Sand fly exposures with 80 unfed females were performed before the first treatment for allocation purposes and post-treatment on study days (SDs) 1, 7, 14, 21 and 28 (following first or second monthly treatment for Studies 1 and 2, respectively). After 60&#xa0;min, sand flies were assessed for mortality and engorgement status. RESULTS: Repellent evaluation (anti-feeding effect) on all days post-infestation showed efficacies that ranged between 88.1-99.3% during the first month and 92.2-98.9% during the second. Analyses of the comparison of fed sand fly counts for each treatment group resulted in a highly significant reduction (P&#x2009;<&#x2009;0.0001) at all post-infestation time points for those dogs treated with Advantix&#xae;. A significant (P&#x2009;<&#x2009;0.0001 for all time points) insecticidal effect was equally demonstrated. No treatment related adverse events were observed during the study. CONCLUSIONS: In the present studies Advantix&#xae; Spot-on demonstrated to be safe and to provide excellent four-week sand fly (P. perniciosus) repellency of &#x2265;88.1% and &#x2265;92.2% after a first and second monthly treatment, respectively. A significant insecticidal effect was also observed.