Colorado animal health officials are hoping that an outbreak of equine herpes affecting horses in multiple states will fizzle out before they have to talk about changing operations at the National Western Stock Show.
One horse in Colorado is confirmed to have the highly contagious and sometimes fatal virus, and 30-40 other horses that recently traveled to events in Texas and Oklahoma are in quarantine as their owners watch for symptoms.
“We are in the early stages of this,” Colorado State Veterinarian Maggie Baldwin said this week in an interview. “We don’t want anybody to panic. We just want people to really be proactive in this and take appropriate precautions.”
The situation is serious enough that state veterinarians across the country joined a call to hear about the outbreak that seems to have originated in Texas or Oklahoma and spread to other states after horses mingled at rodeos, and specifically, an elite barrel racing event in Waco, Texas. The virus, spread through nasal discharge or airborne droplets, typically starts with a fever and can lead to neurological issues, including the inability to stand or walk.
Soon after that nationwide call, Baldwin’s team called the Colorado horse owners whose names were on event participant lists shared by Texas and Oklahoma. “They all understood the concerns associated with this,” she said, noting that word of the outbreak spread quickly through the horse community. “Almost all of them knew about it ahead of time and they were already isolating and monitoring their horses before we reached out.”
The potentially exposed horses should stay separated from other horses for 21 days, Baldwin said. The horses that are still in Texas or Oklahoma should stay there until the quarantine time is up, she said.
Officials from the National Western Stock Show reached out to Baldwin to talk about how the outbreak might affect the two-week event in Denver, which is less than two months away. Thousands of horses are trailered to the stock show from across the country to compete in rodeos, jumping, reining, dressage and even horse dancing.
The show already has multiple “biosecurity” measures in place, including entry requirements that ensure horses are vaccinated and symptom free. Horses can transmit equine herpes by sharing water buckets, tack or feed. People can spread the virus from one horse to another if they have it on their hands or clothing.
The state veterinarian said she told Stock Show officials that it was too soon to say what more the show needs to do or how the outbreak could affect the event, which begins with a parade Jan. 8.
“We need a week or two to wrap our arms around this and make sure that we’ve got good control of the disease before they make any final decisions,” Baldwin said. “They’re being very proactive, and they are making sure they’ve got good biosecurity protocols in place.”
The hope is that fast action by animal health officials throughout the Southwest and beyond will quickly stop the spread, she said.
Events in other states have been canceled in the past few days, including the Barrel Futurities of American Championships, a premier barrel racing contest in Guthrie, Oklahoma. In New Mexico, officials canceled the Christmas de los Caballos Parade, and in Texas, they called off the Uvalde Rodeo Qualifier.
Equine herpes can lead to equine herpes myeloencephalopathy, which is sometimes fatal. The Colorado horse confirmed to have the virus spiked a fever after returning to Larimer County from Waco, Texas. The horse, which tested positive Nov. 20, has developed signs of the neurological condition, according to the state Department of Agriculture. The mortality rate of the disease is about 30%.
A major outbreak of equine herpes in 2011 stemmed from a superspreader event in Ogden, Utah, and heightened protocol nationwide for surveillance of the disease. The Western National Cutting Horse Event, attended by hundreds of horses, led to 90 herpes infections, including 33 that developed the associated neurological condition. Of those 33, 13 horses died.
The department asks that horse owners report any horses with signs of neurologic disease, including walking instability, lethargy and urine dribbling, to the state veterinarian’s office at 303-869-9130.
The virus is not treatable, though veterinarians will try to manage fever and other symptoms. There is a vaccine for equine herpes, which is recommended for horses that travel frequently, but that vaccine is not effective against this particular strain of the virus, Baldwin said. Equine herpes does not spread to other animals, she said.