Field efficacy of a combination of afoxolaner, moxidectin and pyrantel pamoate against natural infestation with Otodectes cynotis in dogs.

Abstract

Otodectes cynotis is the agent of otodectic mange, a disease affecting wild and domestic felines, canines and mustelids. It is a highly contagious and pruritic condition and a major cause of otitis externa in dogs. This study was designed to verify the efficacy of NexGardPLUS, a combination of afoxolaner, moxidectin and pyrantel pamoate, against natural O. cynotis infestations in dogs. It was a blinded, randomised, single-centre, negative controlled clinical efficacy study. Twenty-four naturally infested dogs were allocated to three groups of eight dogs: an untreated control group, a group treated on Day 0 and a group treated on Days 0 and 29 (both groups were treated per label recommendations). Otoscopic examinations were performed on Days -3, 14, 29, 42 and 55 for clinical otodectic mange evaluation. Ear canal flushings were performed on Day 56 for O. cynotis counts, the primary variable of efficacy, calculated per comparison of live mites in the treated groups, with the untreated control group. The otoscopic examinations revealed treatment effect by Day 14 and a highly significant effect by Day 29, while the conditions remained unchanged or worsened in the untreated control group. The O. cynotis counts revealed reductions of 100% in the group treated once on Day 0 (p = 0.0004) and 99.7% (p = 0.0006) in the group treated on Days 0 and 29, while 48.8 (geometric mean) live mites were collected in the untreated control group. NexGardPLUS was demonstrated to be highly efficacious in dogs naturally infested with O. cynotis following one or two treatments.