The Washington State University College of Veterinary Medicine confirms a horse has tested positive for the neurologic form of equine herpes virus (EHV-1). The barrel racer is being euthanized.
Officials said the horse has been in isolation at the Veterinary Teaching Hospital in Pullman since its arrival Thursday. The 18-year-old Quarter Horse from Newport competed in rodeo events in the inland Pacific Northwest, until the mare developed symptoms.
Symptoms that should alert horse owners to the possibility of a neurologic EHV-1 infection include fever of over 102 degrees, weakness, incoordination, and urine dribbling or the inability to urinate. Horses with these symptoms should be examined immediately by a veterinarian.
EHV-1 can spread through various methods. Direct, horse-to-horse contact is a common route of transmission, but indirect transmission is also possible. This occurs when infectious materials are carried between infected and non-infected horses by people or inanimate objects such as buckets, tack, or trailers.
Aerosol transmission can also occur when infectious droplets are inhaled. The source of infectious droplets is most often respiratory secretions.
There is no vaccine currently on the market that has a label for the prevention of the neurologic form of EHV-1.
The Washington State Department of Agriculture and the state veterinarian have been notified. The last EHV-1 outbreak in the state was in May 2011.