Efficacy of Revolution® Plus (selamectin plus sarolaner) against Amblyomma americanum (lone star ticks) in cats.

Abstract

BACKGROUND: The efficacy of a topical combination product, Revolution&#xae; Plus, containing selamectin and sarolaner was evaluated for efficacy against Amblyomma americanum ticks in cats. METHODS: Four laboratory dose confirmation efficacy studies were conducted in different geographical regions of the USA using three distinct US isolates of A. americanum. In each study, ten domestic short-hair cats were randomly allocated to each treatment group based on pretreatment host-suitability tick counts. Cats were infested with approximately 50 unfed adult ticks on day -2. On day 0, cats received either a topical placebo or a single topical dose of Revolution&#xae; Plus at the minimum dosage of 6.0&#xa0;mg/kg selamectin&#x2009;+&#x2009;1.0&#xa0;mg/kg sarolaner. Cats were re-infested with approximately 50 unfed adult ticks each on days 5, 12, 19, 26, and 33. Tick counts (comprising live attached and live free ticks) were conducted at 72&#xa0;h post-treatment and after each subsequent weekly re-infestation. RESULTS: No treatment-related adverse reactions occurred in any study. In all studies, placebo-treated cats maintained adequate infestations for the entire study duration, and cats treated with Revolution&#xae; Plus had significantly lower (P&#x2009;<&#x2009;0.0001) least squares mean live (attached and free) tick counts than placebo-treated cats at all time points for at least 1 month. Revolution&#xae; Plus provided a mean of >&#xa0;90% effectiveness based on least squares means 72&#xa0;h after treatment of existing infestations, and maintained >&#xa0;99.1% effectiveness 72&#xa0;h after re-infestation through at least day 29. CONCLUSIONS: A single dose of Revolution&#xae; Plus administered topically at the minimum label dose of 6.0&#xa0;mg/kg selamectin&#x2009;+&#x2009;1.0&#xa0;mg/kg sarolaner provided treatment and control of A. americanum on cats for at least 1 month.