Aspectos clínicos e epidemiológicos da miosite imunomediada em equinos quarto de milha no Brasil

Abstract

Quarter horses stand out in equestrian sports worldwide, in that context they are frequently prone to myopathies from a variety of etiologies. Among them immune mediated myositis (IMM) that was associated with an E321G missense mutation in myosin heavy chain 1 (MYH1) gene. Field veterinarians have reported several cases of myopathy in quarter horse and related breeds foals presenting clinical signs compatible with IMM, in many of these animals the disease was diagnosed by genetic testing. Furthermore it is known that the immune system in horses with the MYH1 mutation can be triggered by an enviromental stimulus that initiates the clinical signs. As such, the aim of this study was to develop a questionnaire for veterinarians in the area who treated animals with IMM to describe clinical and epidemiological aspects of the disease. The results showed that previous infecction with Streptococcus equi.(61,9%) and vacines including Influenza and herpes vírus-1 (42,85%) can be triggering factors. All the cases ocurred in Brazilian reining quarter horses, this highest prevalency may contribute to disseminate information that facilitates the clinical suspicion and diagnosis by the veterinarians in the area.