Udeni Balasuriya, BVSc, MS, PhD, professor at the University of Kentucky (UK) Gluck Equine Research Center, recently spoke at a UK Equine Forum meeting where he discussed “Equine Infectious Diseases in the Genomic Era: Identification of Putative Host Factors Associated with EAV (Equine Arteritis Virus) Carrier State in the Stallion.”

EAV is a virus that causes equine viral arteritis (EVA), an upper respiratory tract and reproductive disease in horses. EAV can be transmitted by respiratory or venereal routes. Clinical signs of EVA include skin rash; watery eyes; swelling of the eyes; edema (fluid swelling) on the legs, sheath and scrotum; and establishment of persistent infection in stallions. Most EAV infections are subclinical in nature but animals develop moderate to severe clinical signs. The severity of the clinical signs is determined by many factors, including the strain of EAV, route of infection, age, sex, breed, immunity, climate, and management practices. Standardbreds and European Warmbloods have the highest seroprevalence, or disease occurrence within a population, followed by the American Saddlebred. Thoroughbreds and American Quarter Horses have low seroprevalence of EAV.

Balasuriya’s research focus is to identify the viral and host factors involved in the establishment of EAV carrier state in the stallion. The identification of the host factors was made possible by sequence analysis of equine genome from EAV carrier and noncarrier stallions. Balasuriya’s work has identified two genes that may be associated with the establishment of EAV carrier state in stallions. These two genes encode for two proteins (CXCL16 and CXCR6) that are present in equine cells associated with the immunity. This research is important to the equine industry because of EAV’s threat to the breeding industry. Persistently infected stallions can transmit the virus to susceptible mares during breeding and precipitate EVA outbreaks. Furthermore, virus can be transmitted to a naïve recipient mare via embryo transfer from a donor mares inseminated with EAV-infective semen.

In early 2013, Balasuriya was awarded a five-year $2.9 million grant from the U.S. Department of Agriculture to identify genetic factors responsible for the establishment of EAV. The grant is titled “Identification of genetic factors responsible for establishment of equine arteritis virus carrier state in stallions