Treatment and control of Haemaphysalis longicornis infestations on dogs using a formulation of sarolaner, moxidectin and pyrantel (Simparica Trio®).

Abstract

BACKGROUND: Simparica Trio(Zoetis), an orally administered combination product for dogs containing sarolaner, moxidectin and pyrantel pamoate, was evaluated against Haemaphysalis longicornis, a tick species originally native to Asia but now found on multiple continents, including North America. METHODS: Two groups of eight dogs each were ranked based on pretreatment tick counts and then allocated through randomization to treatment on Day 0 with a single dose of either placebo or Simparica Trio at the minimum label dose of 1.2&#xa0;mg/kg sarolaner, 24&#xa0;&#xb5;g/kg moxidectin and 5&#xa0;mg/kg pyrantel (as pamoate salt). Dogs were infested with 50 viable adult H. longicornis on Days -2, 5, 12, 19, 26 and 33. Tick counts were conducted for all dogs 48&#xa0;h after treatment and subsequent re-infestations. RESULTS: Simparica Trio was 98.9% effective in treating existing H. longicornis infestation when considering live attached (feeding) ticks. Efficacy remained&#x2009;>&#x2009;98% in preventing re-infestation for at least 35&#xa0;days, and the geometric mean live attached tick counts for Simparica Trio-treated dogs were significantly lower than for placebo-treated dogs (P&#x2009;<&#x2009;0.0001) at all timepoints assessed in the study. Dogs treated with Simparica Trio also had significantly lower (P&#x2009;<&#x2009;0.0001) geometric mean total live (attached and free) tick counts than placebo-treated dogs at all times. No adverse events were reported for any dogs throughout the duration of the study. CONCLUSIONS: A single administration of Simparica Trio at minimum label dose was efficacious in treating and controlling adult H. longicornis in dogs for more than one month.