Sixth case of deadly equine virus confirmed in Flathead County

A sixth confirmed case of equine herpesvirus myeloencephalopathy in Flathead County has prompted state officials to extend their recommendation that area horse owners and event coordinators limit travel and cancel events in the area.

The recommendation, which originally covered events through Feb. 6 has been extended through Feb. 17.

Equine herpesvirus myeloencephalopathy is a form of a potentially serious type of equine herpes virus, which can cause respiratory or neurologic disease in affected horses, but does not affect other animals or humans. The neurologic form, equine herpes myeloencephalopathy is often fatal to horses.

The new case, diagnosed at a local event/boarding facility, resulted in the euthanization of the horse, the fifth animal to be put down since the outbreak began.

While the Montana Department of Livestock declined to name the affected facility, it confirmed the location had hosted rodeo events in the past few weeks.

“All of them (infected horses) have attended events at this event arena in the past month and a half. They have had some horses coming in from the outside and have tried to mitigate the risks, but ultimately one of their own horses broke,” Montana State Veterinarian Martin Zakuski said. “This arena has some resident horses and a boarding facility. We became concerned that we have not yet been successful in breaking the cycle of infection and it looks as if there are a fair number of potential additional exposures.”

According to Zaluski, the facility where the new infection was detected has been quarantined for the next 21 days, but that might not be enough to contain the contagion.

“We think the primary way this disease is spread is not necessarily horse-to-horse. We believe that human traffic plays a strong role,” he said. “That means things like moving horses back and forth and carrying shared tack and other equipment. Any common areas or shared surfaces can be contaminated. Horses do not have to be nose-to-nose to spread this.”

While Zaluski said the Department of Livestock has not received a list of horse owners who attended events at the arena, event organizers are contacting those who might be affected.

Despite the effort, he said it may be nearly impossible to track down “every client or person that has gone to one of the events.”

Despite the severity of the disease, Zaluski said area horse owners should remain calm.

“I want to make sure people have this situation in perspective. This can be a very devastating disease for the animals that are impacted, but we are talking about six horses in a population of several thousands,” he said. “People with animals that have not traveled to events or been around horses that have traveled in the past 14 days are probably not at increased risk. That being said, in half of these cases so far, the horses have not been traveling, which is concerning. This disease seems to be spread quite readily and we are really just trying to find a way to break that cycle right now.”

Zaluski recommends that horse owners who have attended events in the Flathead Valley in recent weeks should monitor their animals for fever (temperature greater than 101.5 degrees Fahrenheit) or development of any neurologic signs for two weeks after their last travel.

Neurologic signs can include incoordination, difficulty walking, weakness, paralysis, inability to stand, poor tail tone and difficulty urinating.

Horses infected with the virus may also have respiratory signs such as cough, nasal discharge, lethargy and decreased appetite.

Horse owners who see signs of infection and are concerned about the health of their horses should contact their veterinarian. Suspected cases should also be reported to the department and horse owners should work with their local veterinarians on biosecurity recommendations to help reduce disease spread.

Reporter Jeremy Weber can be reached at jweber@dailyinterlake.com.