Equine coital exanthema caused by equid alphaherpesvirus 3: a report of an outbreak in northeastern Brazil

Abstract

Equine coital exanthema is a venereal infectious disease poorly reported in horses in Brazil and was never described in the northeastern region of the country. This work aims to describe the clinical and pathological aspects of an outbreak of equine coital exanthema caused by equid alphaherpesvirus 3, occurred in a herd of horses at the semiarid region of the State of Rio Grande do Norte. Main clinical signs consisted of anorexia, hiporexia, fibrinous or purulent secretion in the penis mucosa and vagina. Two mares presented mild to minimal lesions that consisted of scars in the mucosa of the vagina and in the perivulvar region. In a stallion the disease consisted of severe, multifocal, umbilicated-exanthematous ulcers of approximately 1cm in diameter on the penis mucosa. Other areas where ulcers and crusts were focally observed included the skin of the scrotum and on the lips and mucocutaneous junctions of the oral cavity. Histologically, the main lesion consisted of multifocal severe ulcerative and fibrinous necrotizing balanoposthitis and mild multifocal necrotizing, lymphocytic dermatitis in the lips and scrotum. The equide alphaherpesvirus 3 DNA was amplified in blood samples and penis mucosa using the PCR technique. This is the first report of molecular diagnosis of equine coital exanthema affecting horses in northeastern Brazil. Further studies should be carried out in order to investigate the epidemiology and the importance of this herpetic disease in the country.

Male reproductive tract disorders in equids: 87 cases (2014-2022)

“…Phimosis, ulcerative posthitis, epididymitis, hydrocele, and papillomatosis accounted for only 1% of each (1/100) of all cases in our hospital attendance routine. Ulcerative posthitis is an uncommon disease in Brazilian horses, and usually, infectious agents, such as equid Alphaherpesvirus 3, the etiologic agent of equine coital exanthema, are observed (Silva-Filho et al 2021). Infections by equine arteritis virus, various bacteria, and nematodes have also been associated with cases of epididymitis in horses (Snider 2015).…”