Acaricidal efficacy of topical formulation of fipronil in naturally infested dogs in Amazonic region, Brazil.

This study was conducted to show the effectiveness of a novel formulation of fipronil in a spot-on formulation for the therapeutic and preventive control of Rhipicephalus sanguineus in naturally infested dogs. Ticks on all dogs were counted at the moment of treatment and weekly after treatment (therapeutic efficacy) or infestation (preventive efficacy). The profile of the therapeutic efficacy for Rhipicephalus sanguineus suggested that the formulation was able to control the Ixodid species for at least 42 days after the treatment.