Oregon officials confirm four horses have now tested positive for the equine herpes virus (EHV-1). Two of the horses are showing neurological symptoms associated with the disease, according to the Oregon Department of Agriculture.
The index horse, from Marion County, tested positive for the neurological form of the virus last week.
A second horse from Polk County developed neurological symptoms over the weekend. It is being treated at Oregon State University’s College of Veterinary Medicine. About 40 horses reside at the Polk County stable that is now under quarantine.
Two Marion County farms are also still under quarantine due to exposure. The infected and exposed horses attended an Oregon High School Equestrian Team (OHSET) meet at the Linn County Fairgrounds on April 16-19. ODA is currently investigating the potential of any additional exposures at this time.
“The detection of neurologic EHV-1 is taken very seriously, and we are doing our best to notify equine veterinarians and horse owners,” said State Veterinarian Dr. Brad LeaMaster. “We have had occurrences of the disease in Oregon in the past. I appreciate everyone’s cooperation in dealing with the disease investigation and control process.”
EHV-1 may lie dormant for long periods of time and then re-activate during a period of stress, which can result in clinical disease.
Symptoms may include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy, and the inability to rise. While there is no cure, the symptoms of the disease may be treatable.
Veterinarians recommend using proper biosecurity measures when attending equine events to help protect your horses from the potential spread of any illness:
· Limit horse-to-horse contact.
· Limit horse-to-human-to-horse contact.
· Avoid use of communal water sources.
· Avoid sharing of equipment unless thoroughly cleaned and disinfected between uses.
· Monitor your horse for clinical signs of disease and report any temperature over 102°F to a veterinarian.
For more information, contact your local veterinarian.