Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against ear mite (Otodectes cynotis) infestations in cats.

Eric Tielemans,Otsuki Tomoko,Despoina Kostopoulou,Smaragda Sotiraki,Balázs Capári,Martin Knaus,Joe Prullage,Julian Liebenberg,Michael Ulrich,Panagiota Ligda

doi:10.1051/parasite/2021022

Abstract

Esafoxolaner, a purified enantiomer of afoxolaner with insecticidal and acaricidal properties, is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in NexGard® Combo, a novel topical endectoparasiticide formulation for cats. The efficacy of this formulation was assessed against Otodectes cynotis in two laboratory studies conducted in South Africa and in the USA with local isolates, and in one field trial conducted in Europe. In each study, cats were randomly allocated to a placebo-treated control group and a novel formulation-treated group. In the laboratory studies, cats were treated at the minimum recommended dose; in the field trial, cats were treated at label dose. All included cats were diagnosed positive for O. cynotis prior to treatment by otoscopy. The main variable of efficacy was a comparison of the number of live O. cynotis collected in both ear canals of all cats in the treated and control groups, one month after treatment. Efficacy of the novel topical formulation exceeded 97% in the three studies. These studies demonstrated the high effectiveness of NexGard® Combo in cats for the treatment of O. cynotis infestations. No health abnormalities were attributed to the treatment in any of the studies.

Highlights

The ear mite Otodectes cynotis is one of the major ectoparasites of cats and a primary cause of otitis externa [13, 33]
The results of these three studies provide a robust demonstration of the high level of efficacy of NexGardÒ Combo for the treatment of O. cynotis infestations, in induced and natural infestation models in laboratory and field studies, in Europe, the United States, and South Africa, with efficacy results of a single treatment exceeding 97% each time
In Lab #1 and the Field study, the studies with highest infestation levels, even though treatment efficacy was demonstrated, some of the treated cats still had a significant number of mites in their ear canals one month after treatment

Summary

Introduction

The ear mite Otodectes cynotis is one of the major ectoparasites of cats and a primary cause of otitis externa [13, 33]. In a multi-centric survey conducted on domestic cats randomly presented in veterinary clinics for reasons unrelated to parasitic disease, in seven countries in Southern and Central Europe, ear mites were diagnosed in 17.4% of 1519 cats [4]. In another survey conducted in Greece, 25.5% of domestic cats were diagnosed ear mite-positive [27]. Otodectes cynotis is pathogenic in young cats, dogs and ferrets, and is directly transmitted from one animal to another [19, 23] It was identified as the primary cause of otitis externa in 53.3% of 187 stray cats [20]. The correlation between clinical signs and number of O. cynotis can be inconsistent: one or two mites have been seen to cause severe otitis lesions with large amounts of dark cerumen, while 50 to 100 mites have been found in clean ear canals [8]

Methods

Results

Conclusion