Equine Viral Arteritis Study Guide

Overview and Clinical Importance

Equine viral arteritis (EVA) is an economically important, contagious viral disease of equids caused by equine arteritis virus (EAV). The virus was first isolated in 1953 following an outbreak of respiratory disease and abortion on a Standardbred breeding farm in Bucyrus, Ohio. The disease derives its name from the characteristic panvasculitis affecting small arteries and venules throughout the body.

EVA is of significant veterinary and economic importance because it can cause: abortion in pregnant mares with rates as high as 60% in naive populations, fatal interstitial pneumonia in neonatal foals, and establishment of a long-term carrier state in stallions. The carrier stallion is the critical natural reservoir of EAV, as venereal transmission frequently occurs during breeding.

Etiology

Virus Classification and Structure

EAV is classified as a member of the family Arteriviridae, genus Alphaarterivirus, order Nidovirales. The virus has been officially renamed Alphaarterivirus equid. It is the prototype virus of the Arteriviridae family, which also includes porcine reproductive and respiratory syndrome virus (PRRSV), simian hemorrhagic fever virus (SHFV), and lactate dehydrogenase-elevating virus (LDV) of mice.