Efficacy of a proprietary formulation of fipronil/(S)-methoprene/cyphenothrin against Ixodes scapularis tick infestations on dogs

Background: efficacy of frontline® tritak® for dogs (fipronil/(s)-methoprene/cyphenothrin,merial,inc.,duluth,ga) against ixodes scapularis was evaluated in two separate,but concurrent laboratory studies. methods: one day after topical treatment with placebo or active,dogs (n∈=∈24) were infested with 50 unfed adult ixodes scapularis ticks,with repeat infestations on days 7,14,21 and 28. the number of live ticks was counted at 6 hours post-infestation in the first study (n∈=∈12) and at 24 hours post-infestation in the second study (n∈=∈12). results: observed efficacies in study 1 were 93-99 % at 6 hour assessments on day 1 through day 28 and in the second study,98-100 % at 24 hour assessments,occurring on day 2 through day 29. conclusions: a single dose of frontline® tritak® for dogs (fipronil/(s)-methoprene/cyphenothrin) (0.67 ml or 1.34 ml) prevented the establishment of a new infestation following treatment,as well as the repeated weekly re-infestations with ixodes scapularis ticks,for 4 weeks. © 2015 carithers et al.