Anatomopathological changes in canine distemper seropositive dogs and virus detection in sinoatrial nodes

José Eugenio Diniz Bastos,Neide Maria Silva,Alessandra Aparecida Medeiros-Ronchi,Tais Meziara Wilson,Marisol Patrícia Pallete Briceño

doi:10.14393/bj-v36n1a2020-42122

José Eugenio Diniz Bastos, Neide Maria Silva + Show 3 more

Open Access

https://doi.org/10.14393/bj-v36n1a2020-42122

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Abstract

Canine distemper is a viral disease that affects several systems on dogs, among them, the cardiovascular system. The aim of this study was to identify canine distemper virus (CDV) in the sinoatrial node (SAN) of dogs serologically positive for distemper by Polymerase Chain Reaction preceded by reverse transcription (RT-PCR), and to analyze gross and microscopic changes of distemper in the heart and other tissues. SAN and tissue fragments were collected from 17 serologically positive dead animals, necropsied from October 2015 to December 2016. In the heart, right heart dilatation was observed in 13 dogs (76.47%) and left concentric hypertrophy in two dogs (11.76%). Microscopically, lymphocytic myocarditis was observed in four (23.53%) dogs and 41.18% presented viral inclusion corpuscles of CDV in the bladder epithelium. Only one (5.88%) dog presented a 319 bp target fragment for distemper virus using primers CDV 1 and CDV 2 at the sinoatrial node. In conclusion, CDV can be located in the sinoatrial node of naturally infected dogs, as demonstrated in this study by the RT-PCR technique, reinforcing the hypothesis that CDV is capable of causing inflammatory lesions in the sinoatrial node of this species. Macroscopic and microscopic cardiac changes are frequently observed in dogs with distemper, mainly cardiac dilatation and myocarditis. Viral inclusions of CDV in bladder epithelial cells are an important microscopic finding for the diagnosis of distemper.

Highlights

The sinoatrial node (SAN) is responsible for the heart rhythm and is essential for the normal physiology of the heart (JOUNG et al, 2011)
Nelson and Couto (2015) reported that cardiotropic viruses play an important role in the pathogenesis of myocarditis in several species
The disease can reach dogs of different ages and the incidence of major distemper cases occurs between 60 and 90 days of age (CORRÊA; CORRÊA, 1992). These same authors reported that the disease may develop in animals from 7 to 9 years old, the age observed in the present study, but the lethality is higher in young dogs especially when the virus acts on the central nervous system (CORRÊA; CORRÊA, 1992)

Summary

Introduction

The sinoatrial node (SAN) is responsible for the heart rhythm and is essential for the normal physiology of the heart (JOUNG et al, 2011). His bundle together with the atrioventricular node and the Purkinge fibers are the specialized conduction system of the heart (CUNNINGHAM; KLEIN, 2008). Monfredi et al (2010) and Andrade et al (1988) reported that the SAN shows an increasing density as the age progresses and that sinoatrial node dysfunction can be considered an aging phenomenon. Information about microorganisms that affect the canine SAN are rare. The possibility of canine distemper virus (CDV) causing injury in this area as suggested by Mendonça and Coelho (2006) raised interest about the presence of the virus in this cardiac structure. Nelson and Couto (2015) reported that cardiotropic viruses play an important role in the pathogenesis of myocarditis in several species

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