Comparative speed of kill of sarolaner (Simparica®) and afoxolaner (NexGard®) against induced infestations of Ixodes holocyclus on dogs

Abstract

BackgroundThe Australian paralysis tick, Ixodes holocyclus, causes paralysis predominantly in dogs and cats in the Eastern coastal regions of Australia. Rapid onset of effect of a parasiticide is critical to minimize the deleterious effects of these tick infestations, especially tick paralysis caused by the salivary neurotoxin. The speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner chewable tablets (Simparica®), against I. holocyclus on dogs was evaluated and compared with afoxolaner (NexGard®) for 5 weeks after a single oral dose.MethodsTwenty-four (24) dogs were randomly allocated to treatment with either placebo, sarolaner (label dose of 2 to 4 mg/kg as per dosing table), or afoxolaner (label dose of 2.7 to 6.9 mg/kg) based on pre-treatment body weights. Following artificial infestation on Day -1, dogs were examined and live ticks counted at 8, 12, 24 and 48 h after treatment on Day 0, and at 12, 24 and 48 h after subsequent re-infestations on Days 7, 14, 21, 28 and 35. Efficacy was determined at each time point relative to counts for placebo dogs based on geometric means.ResultsAt 8 and 12 h time points on Day 0, sarolaner-treated dogs had significantly lower geometric mean tick counts compared to the dogs treated with afoxolaner (P ≤ 0.0303). Efficacy of sarolaner against an existing infestation was 86.2 and 96.9% compared with that of afoxolaner which had efficacy of 21.3 and 85.0% at 8 and 12 h time points, respectively. Against subsequent weekly re-infestations at 12 h time points, treatment with sarolaner resulted in significantly lower geometric mean tick counts than afoxolaner-treated dogs on all days (P ≤ 0.0077) with the efficacy ranging from 60.2 to 92.2%, compared to 5.8 to 61.0% in the afoxolaner-treated dogs. Against subsequent weekly re-infestations at the 24 h time points on Days 22 and 36, efficacy of sarolaner was significantly higher at 99.2 and 97.9%, respectively, compared with afoxolaner which had efficacy of 92.4 and 91.9% (P ≤ 0.0356). At the 48 h time points following each of the five weekly re-infestations, the mean efficacy results of sarolaner and afoxolaner treated dogs were similar on most occasions. There were no adverse reactions to treatments.ConclusionsIn this controlled laboratory evaluation, a single dose of sarolaner had a significantly faster speed of kill against an existing infestation of I. holocyclus, than afoxolaner at 8 and 12 h post-treatment. The rapid and consistent kill of ticks provided by sarolaner within 24 h after a single oral dose and following weekly re-infestations over 35 days suggests this treatment will provide highly effective, rapid and reliable control of ticks over the entire treatment interval, thereby minimizing the risk of tick paralysis in dogs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2024-9) contains supplementary material, which is available to authorized users.

Laboratory evaluations of the 3-month efficacy of oral lotilaner (Credelio™) against experimental infestations of dogs with the Australian paralysis tick, Ixodes holocyclus

“…The findings of lotilaner efficacy against I. holocyclus in this study parallel those of a report of the efficacy of sarolaner and afoxolaner in eliminating existing burdens and post-treatment infestations through 35 days after treatment [ 19 ]. Extending well beyond the findings of that study, we have demonstrated the potency of lotilaner in providing a high level of efficacy through at least 12 weeks after treatment against I. holocyclus when evaluated at 72 h post-treatment or re-infestation.…”

Efficacy of combination products containing sarolaner, moxidectin and pyrantel (Simparica Trio™) or afoxolaner and milbemycin (NexGard Spectra®) against induced infestations of Ixodes holocyclus in dogs

“…Both free and attached ticks were characterized as either live or dead as described previously [ 58 ]. Moribund ticks were characterized and included in the live counts as previously described [ 49 ]. All the tick counts and assessments were performed by laboratory technicians who were experienced and trained on validated laboratory methods of tick counting and assessments.…”

“…Sarolaner (Simparica™, Zoetis) chewable tablet dosed at 2 mg/kg body weight, a potent ecto-parasiticide, has excellent efficacy against ticks, fleas and mites [ 6 ] and has been demonstrated to provide rapid and sustained efficacy against I. holocyclus [ 49 ]. To broaden the spectrum of activity, a new novel oral chewable combination product delivering 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel (Simparica Trio™, Zoetis) has been approved in USA, Canada, Europe and Australia.…”

Recent Advancements in the Control of Cat Fleas

“…In a laboratory study with dogs, an oral dose of sarolaner provided 86.2 and 96.5% reductions in Ixodes holocyclus at 8 and 12 h, respectively whereas an oral dose of afoxolaner provided 21.3 and 85.0% reductions at 8 and 12 h, respectively. When treated dogs were challenged at day 35, sarolaner and afoxolaner provided 65.2 and 21.0% efficacy at 12 h, respectively [ 77 ]. Oral doses of sarolaner, moxidectin, and pyrantel to laboratory dogs provided 99.7% reductions in C. f. felis for at least 35 days with no eggs being laid during the 35 days.…”