Equine Viral Arteritis (EVA) is a contagious disease, especially
among certain breeds of horses. The virus is transmitted by
aerosol inhalation from respiratory secretions and semen of
After one to six days, symptoms begin as a serous nasal
discharge that can become purulent, and swollen lymph nodes.
A cough, fever and depression occur with a notable, severe
edema of the abdomen, legs, face and mammary or prepuce/
scrotum area. Abortions develop during or shortly after the
febrile period, 60 to 330 days into gestation.
A vaccine is available for horses that may be exposed during
breeding seasons. After injection, the horse is quarantined for
three weeks while it sheds the virus. A blood test is taken
before and after to determine the horse's serum titer to EVA. The
vaccine is an annual booster and should not be given to foals
less than six weeks old or pregnant mares during the last two
months of pregnancy. It is important to identify carrier
stallions that are shedding the virus in order to control the
spread of EVA.