Equine veterinarians at the University of Minnesota College of Veterinary Medicine have diagnosed three cases of neurologic equine herpesvirus-1 (EHV-1) in horses from a single farm in Wright County, Minn.

Because EHV-1 infection was suspected, two of the three cases were admitted into isolation at the large animal hospital, which is a separate facility located a half-mile away from the Leatherdale Equine Center and Piper Performance Clinic. The third case was euthanized on the home farm. The four remaining horses on the farm are being monitored closely at home.

Tests from one of the hospitalized horses yielded confirmation of EHV-1 infection on Nov. 14 and tests from the second horse are pending. Since the farm of origin has been closed to on- and off-farm horse traffic for at least the past six months, there is a very little chance that additional horses have been exposed as part of this outbreak.

Equine herpesvirus-1 is a highly contagious virus in horses that can cause respiratory disease, abortion, and intermittent outbreaks of neurologic disease. There is no evidence that additional horses have been exposed in the Wright County outbreak, but clinical signs that should alert horse owners to the possibility of neurologic EHV-1 infection include fever, weakness, ataxia (incoordination), and urine dribbling or inability to urinate. Horses exhibiting these signs should be examined immediately by an equine veterinarian. Horses with a fever and signs of respiratory infection should be quarantined at home and not taken to shows, clinics, or public trail rides. Owners of affected horses should wash and disinfect their hands and change their clothes before coming into contact with healthy horses to avoid the spread of viral or bacterial infections