Efficacy of milbemycin oxime/afoxolaner chewable tablets (NEXGARD SPECTRA\xae) against Capillaria aerophila and Capillaria boehmi in naturally infected dogs

Angela Di Cesare,Mariasole Colombo,Giulia Morganti,Wilfried Lebon,Giulia Simonato,Michele Berlanda,Donato Traversa,Frederic Beugnet,Matilde Gallo,Fabrizia Veronesi,Simone Morelli

doi:10.1186/s13071-021-04648-y

Abstract

BackgroundCapillaria aerophila and Capillaria boehmi parasitize the respiratory system of wild and domestic carnivores. Capillaria aerophila inhabits the trachea and bronchi of dogs and cats, while C. boehmi affects the nasal cavities and sinuses of dogs. In dogs the infection may be subclinical or characterized by varying respiratory distress.MethodsThe present study evaluated the efficacy of an oral formulation containing milbemycin oxime and afoxolaner (NEXGARD SPECTRA®) in dogs naturally infected with C. aerophila and/or C. boehmi from three enzootic areas of Italy. Dogs were enrolled pending fecal examination and molecular confirmation of respiratory capillarioses. Dogs were allocated in two groups: Group 1 (G1, 25 dogs), treated with a negative control product with no anthelmintic activity (afoxolaner, NEXGARD®), and Group 2 (G2, 26 dogs), treated with NEXGARD SPECTRA®. At the day of treatment administration (Day 0), all dogs were clinically examined. Dogs were again subjected to clinical and fecal examinations at Days 28 (± 4) and 56 (± 2). The primary criterion for treatment efficacy was the reduction of fecal Capillaria egg counts in G2 compared with G1. The regression of/recovery from baseline clinical signs was considered as a further efficacy criterion.ResultsPercentage reduction of fecal Capillaria egg counts in the NEXGARD SPECTRA® group compared to the control group was > 97% on Day 28 and 100% on Day 56, respectively (p < 0.05 for both time points). Twelve of the 13 dogs in the NEXGARD SPECTRA® group with respiratory signs prior to treatment were free of clinical signs at the end of the study. Conversely, the six control group dogs with respiratory signs prior to treatment remained symptomatic.ConclusionsResults of the present study showed that NEXGARD SPECTRA® was safe and highly efficacious in the reduction of C. aerophila and C. boehmi eggs after one treatment with a complete reduction of the egg output after the second administration associated with a recovery from respiratory signs.Graphical

Highlights

Capillaria aerophila and Capillaria boehmi parasitize the respiratory system of wild and domestic carnivores
138 dogs tested negative for Capillaria eggs and 51 dogs testing positive for Capillaria eggs were enrolled in the study, i.e. 20, 20 and 11 at Sites A, B and C, respectively
Twenty-five and 26 dogs were allocated to groups Group 1 (G1) and Group 2 (G2), respectively

Summary

Introduction

Capillaria aerophila and Capillaria boehmi parasitize the respiratory system of wild and domestic carnivores. Adults of C. aerophila live underneath the epithelium of trachea and bronchi of wild carnivores, dogs, cats, mustelids and occasionally humans, while those of C. boehmi inhabit the nasal turbinates. Infections by C. aerophila and C. boehmi are increasingly reported in domestic carnivores, probably as a result of the access to wild environments and the arrival of wildlife to urban and peri-urban areas [3, 5,6,7,8,9,10,11,12]. Depending upon parasite burden and microbial co-infections, dogs infected by C. aerophila may present a subclinical picture or pulmonary capillariosis characterized by chronic bronchitis, bronchopneumonia and respiratory failure. Cerebral damage due to intracranial migrations of parasite elements has been described [17]

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