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

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 mg/kg sarolaner, 24 µg/kg moxidectin and 5 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 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 > 98% in preventing re-infestation for at least 35 days, and the geometric mean live attached tick counts for Simparica Trio-treated dogs were significantly lower than for placebo-treated dogs (P < 0.0001) at all timepoints assessed in the study. Dogs treated with Simparica Trio also had significantly lower (P < 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.