In this experiment, 4 ticks at Day 2 and 6 ticks at Day 16 were recovered from one control dog. It is below the 20% of attachment rate proposed by Marchiondo et al. (2013). Nevertheless the geometric mean count values ranged from 13.9 to 23.7 which were above the 20% attachment

rate. The geometric mean counts were used to calculate the percent efficacy, which is therefore valid based on the guidelines ( Marchiondo et al., 2013). A single oral treatment with the chewable formulation of afoxolaner achieved 100% curative efficacy for treating preexistent infestation of H. longicornis. It also controlled re-infestation by eliminating >90% of the ticks within the first 48 h after infestation for 4 weeks after treatment. The Day 30 efficacy

of afoxolaner seems lower than what has been observed for other tick species mTOR inhibitor ( Kunkle et al., 2014 and Mitchell et al., 2014). This may be related to a lower attachment rate in the control dogs, but also the variability of each experiment. There are some reports on the efficacy of current veterinary topical products against H. longicornis, e.g. imidacloprid/permethrin, fipronil/(S)-methoprene ( Hagimori et al., 2005). However, unlike these topical combinations, ticks are exposed to afoxolaner while feeding on the host’s blood. Afoxolaner is absorbed rapidly by the intestinal mucosa, and its plasma concentration peaks within 2–4 h after administration ( Letendre et al., 2014), which ultimately results in rapid uptake of the active ingredient by the ticks and a tick efficacy assessed at 48 h is similar to that of imidacloprid/permethrin or fipronil/(S)-methoprene selleck chemicals llc combinations ( Hagimori et al., 2005). The systemic distribution offers advantages compared to topical formulations. There is no period after treatment-administration during which the application site should be avoided by the owners and wetting of the haircoat or any other topical treatment does not interfere with the product efficacy. Another product for

oral administration containing spinosad includes a registered claim for H. longicornis tick curative treatment in Japan (Comfortis 1); however, this product is not registered for use against ticks elsewhere ( Beugnet and Franc, 2012 and Snyder et al., 2009). Snyder et al. (2009) reported a limited, short-lasting nearly efficacy of 50 mg/kg spinosad against new tick infestations on dogs with 67.8% efficacy at Day 9, 49.1% at Day 14, dropping to 5% at Day 30, against Rhipicephalus sanguineus by counting ticks 48 h after infestations. In this study, afoxolaner provided both curative and prophylactic efficacy for up to 30 days against H. longicornis. Nexgard® chewable formulation containing afoxolaner represents the first oral ectoparasiticide treatment providing a month-long efficacy against H. longicornis, the main Japanese tick species infesting dogs. The work reported herein was funded by Merial Limited, GA, USA. All authors are current employees of Merial.