Equine viral arteritis — epidemiology and control

The epizootic of equine viral arteritis (EVA) in the Thoroughbred population in central Kentucky in 1984 aroused concern for a disease whose previous sporadic occurrences had gone largely unnoticed. The threat of spread of EVA through the internal movement of horses led to the imposition of considerable restrictions by other major bloodstock-raising countries on the importation of horses of all breeds from the US. Though in no way disputing the importance of spread of the EVA infection at racetracks, sales and equestrian events, etc., it has become evident that the long-term carrier stallion probably plays a major epidemiologic role in perpetuating the virus from year to year. In contrast to the stallion, the carrier state has not yet been confirmed in the mare, nor has there been any evidence of a congenitally acquired carrier state in foals.