Equine Herpes Virus Has Run Its Course

Utah State Veterinarian Bruce King told the Utah Veterinary Association at its annual meeting June 10 that the neurologic form of equine herpes virus spread from a cutting horse show in Ogden has run its course, and the risk is now the same as it was before the event. King said horse owners should now feel free to participate in rodeos, horse shows, parades and other events.

The recent outbreak of the virus was traced to a cutting horse show April 29 to May 8. The Ogden competition drew some 400 horses from 10 western states, including Arizona, California, Colorado, Idaho, New Mexico, Nevada, Oklahoma, Oregon, Utah and Washington, as well as several Canadian provinces.

According to Dr. Kerry Rood, Utah State University Extension veterinarian, of the total 90 confirmed cases of the equine virus, 54 cases were horses that were at the Ogden event. Thirteen horses associated with the incident are dead or have been euthanized.

Rood said Utah horse owners have voluntarily canceled or postponed horse-related events to minimize exposure, and horses exposed at the event have been quarantined at home.

“It is a relief for horse owners that the virus has run its course, and they can now move forward with their summer shows and events,” said Rood. “However, it is still important to be aware of the risks while traveling to competitions.”

He urged horse owners to practice good biosecurity such as not sharing equipment or allowing direct contact between horses.

Rood said that keeping competition horses their healthiest can also minimize the risk of infection.

“I encourage all horse owners to make sure their horse’s herpes virus vaccination is up to date,” he said “While there is no vaccine for the neurologic form, some researchers suggest a possible cross protection that could lessen the severity when the other equine herpes virus vaccines are up to date.” 

Clinical signs of the disease 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. A veterinarian should be contacted immediately if any of these symptoms become present.

Related link:

Utah State University Extension

Contact: Kerry Rood, (435) 797-1882, kerry.rood@usu

Writer: Julene Reese, USU Extension writer, (435) 797-0810, julene.reese@usu.edu