Assessment of the efficacy of orally administered afoxolaner against Rhipicephalus sanguineus sensu lato

Two studies were conducted to confirm that a single oral dose of the novel insecticide/acaricide afoxolaner is efficacious against existing infestations of Rhipicephalus sanguineus sensu lato in dogs and can control re-infestation for up to 35 days. Each study utilized 16 purpose bred adult dogs using a controlled randomized block design. One or two days prior to treatment, all dogs were infested with 50 unfed adult ticks. On Day 0 one group was treated with an oral chewable formulation of afoxolaner at a dose as close as possible to the minimum dose of 2.5mg/kg. Weekly re-infestations with 50 adult unfed ticks were repeated for five weeks. Forty-eight hours after treatment and after each re-infestation, the number of remaining live ticks on each dog was counted. Treatment with afoxolaner resulted in efficacies of 98.8–100% within 48h on existing tick infestations, while the efficacy against new tick infestations was >95.7% over five weeks.