An equine herpes outbreak could impact the National Western Stock Show in January.

Stock Show officials said they are monitoring the situation closely.

The Colorado State Veterinarian’s Office announced the outbreak on Nov. 21, following barrel racing and rodeo events in Texas and Oklahoma over the past several weeks. Horses traveled to or from the events to Colorado, and the owners of the exposed horses have been informed and put under hold orders, according to a news release from the Colorado Department of Agriculture.

Equine Feline Herpes Virus (EHV-1) is a highly contagious virus that can be fatal and cause a serious neurological disease in horses called Equine Herpes Myeloencephalopathy, authorities said.

One of the trace horses from an event in Waco, Texas spiked a mild fever after returning to Larimer County, the release said. The horse tested positive for EHV-1 on Nov. 20. The horse then started having additional neurological symptoms, authorities said.

“This outbreak serves as a reminder of the potential disease risks associated with large commingling equine events,” Colorado State Veterinarian Maggie Baldwin said. “It highlights the need for all horse owners to practice strong biosecurity and report any concerning signs to their veterinarian quickly.”

The news of the outbreak comes less than two months out from Colorado’s National Western Stock Show, which is scheduled for Jan. 10 to 25. The event draws hundreds of horse, cow, sheep and other cattle owners from around the United States – some internationally – to Colorado .

A Stock Show spokesperson told The Denver Gazette that organizers “recently enhanced protocols already in place” and will implement “additional security measures if necessary.”

“We are working in coordination with our veterinary partners, state animal health officials, and the Colorado Department of Agriculture to stay informed and prepared,” the spokesperson said in an email. “NWSS is working to develop a response plan should conditions change and will continue to monitor the situation in the coming weeks.”

There are no current reported cases of EHV-1 associated with NWSS facilities, the spokesperson added.

“We encourage exhibitors to follow best practices for animal health and safety management. NWSS is dedicated to transparency and high standards of animal care for a successful 2026 Stock Show,” the spokesperson said.

Tickets to the 2026 NWSS can be found on the organization’s website.

It’s the 120th year of the event that draws thousands of visitors, exhibitors, business representatives, cowboys and cowgirls to the Mile High City. Last year’s show drew 658,109 visitors over its 16-day run. It was one of the top-10 attended show in its history.

Though it was the 119th year of the Stock Show, it was technically the 118th because government-ordered COVID pandemic shutdowns stopped the 2021 show, the only to be canceled in its entirety.

The kickoff parade is scheduled for Jan. 8 at noon in Downtown Denver.