Herpesvírus em equídeos no Brasil

Abstract

Objective of this dissertation describes the occurrence of an outbreak of coital exanthema caused by alphaherpesvirus equine 3 (EHV-3), in the State of Rio Grande do Norte. The national equine herd is estimated at 5,228,434 heads, comprising 4,236,062 horses (81%), 615,498 mules (11.8%) and 376,874 donkeys (7.2%). Among the important causes of economic damage to an equine culture, respiratory and reproductive disorders stand out, often associated with herpesvirus infection. Five different herpesviruses cause clinical disease in domestic horses, these being equine alphaherpesviruses 1,3 and 4 (EHV-1, EHV-3 and EHV-4) and equine gammaherpesviruses 2 and 5 (EHV-2 and (EHV-5). It is estimated that 80–90% of horses aged up to 2 years old have already been infected with EHV-1 and / or EHV-4. These cause abortions, respiratory accidents and myeloencephalopathy in their hosts. there is no diagnosis of EHV-4 as a cause of disease, with only serological evidence of its presence. The prevalence of these agents demonstrates that donkeys and mules, even though clinically affected, are of fundamental importance in the spread of EHV-1 and EHV-4 in herds. EHV-3 is responsible for causing a reproductive disease called equine coital exanthema (ECE). This disease is characterized by ulcers in the genital regions, donkeys and many can be affected. Gammaherpesvirosis EHV-2 and EHV-5 have been more recently studied, the latter associated with important pulmonary damage in horses, characterized by severe multinodular pulmonary fibrosis in horses, it is suspected that this is a new emerging disease. In Brazil, there is no diagnosis of herpesvirus infections that have donkeys as a host. The outbreak described occurred in a farm in the semi-arid region of the State of Rio Grande do Norte. The main clinical signs consisted of anorexia, hyporexia, fibrinous or purulent secretion in the mucosa of the penis and vagina. Two mares had discrete lesions that consisted of scars on the mucosa of the vagina and on the perivulvar region. In a stallion, the disease consisted of severe umbilicated-exanthematous ulcers, histologically foreskin with necrotizing dermatitis with acanthosis with some keratinocytes containing intranuclear eosinophilic inclusion corpuscle, notable inflammatory infiltrate and perivasculitis. The DNA of EHV-3 was amplified in blood and mucosa samples from the penis by the PCR technique. This is the first report of molecular diagnosis of equine coital rash affecting horses in Northeast Brazil. New studies must be carried out in order to investigate the epidemiology and the importance of this herpetic disease in the country.