Long-term efficacy of an imidacloprid 10 % / flumethrin 4.5 % polymer matrix collar (Seresto®, Bayer) against the Australian paralysis tick (Ixodes holocyclus) in dogs.

Abstract

Two placebo-controlled pen studies were conducted to assess the efficacy of an imidacloprid 10 %/flumethrin 4.5 % polymer matrix collar (Seresto®, Bayer; Investigational Veterinary Product (IVP)) against the Australian paralysis tick (Ixodes holocyclus). Dogs assigned to the placebo (n = 8) or IVP (n ≥ 8) groups had collars (placebo or IVP) attached on Day 0 and were infested with 30 unfed, adult, female I. holocyclus at 14–28 day intervals over 227 days. Ticks were counted 24, 48 and 72 h post infestation to determine the acaricidal efficacy of the IVP. The acaricidal efficacy of the IVP 72 h post infestation exceeded 95 % on Days 17 (99.3 %), 59 (99.7 %), 73 (96.6 %), 87 (100.0 %), 101 (96.4 %), 115 (99.1 %) and 171 (95.8 %), but dropped on Days 45 (94.0 %) and 143 (77.8 %), and declined from Day 199 (79.9 %) to 227 (65.5 %). No adverse events related to treatment were observed. This study has demonstrated the excellent acaricidal efficacy (97.9 %) of the IVP collar against I. holocyclus 72 h post infestation over 16 weeks.