EVA Outbreak and Vaccine Shortage Affects Western U.S.

An outbreak of equine viral arteritis (EVA) resulted in quarantine restrictions in 18 states, with nine states reporting positive cases. A vaccine shortage is hampering efforts to control the outbreak.

Although the virus has been limited to Quarter Horse breeding farms, Peter Timoney, FRCVS, PhD, of the University of Kentucky's Maxwell H. Gluck Equine Research Center, sees an opportunity for transmission into the Thoroughbred industry as the breeds often share the same areas at tracks and are often crossbred.

"Strains of the virus active at this time are clearly abortogenic," said Timoney. "People need to be very careful before they haul horses to racetracks, sales, shows, and breeding farms. New arrivals on breeding farms must be isolated at least three weeks before coming into contact with any other horses, but especially mares in foal."

Restrictions have been placed on horses moving from or to the affected area.

The outbreak has caused a severe shortage of EVA vaccines, with orders backlogged until October, according to Rocky Bigbie, DVM, MS, director of field veterinary services for Fort Dodge Animal Health.

Clinical signs associated with EVA are fever, respiratory illness, ocular inflammation, edema (fluid swelling) of the legs, prepuce, and scrotum, pneumonia or pneumonia enteritis in foals, and abortion. The virus can be spread through semen from infected stallions, infected respiratory secretions, or indirectly through shared breeding shed equipment or tack.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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