Montana Department of Livestock Recommends Extension of Cancellation of Equine Events in Flathead County |

Montana Department of Livestock Recommends Extension of Cancellation of Equine Events in Flathead County

Helena, Mont. – Following the diagnosis of a fourth premises with Equine Herpes Virus 1 (EHV-1) in Flathead County, the Department of Livestock has quarantined an equine event/boarding facility and is extending the recommendation for limiting travel and cancelling events in the valley that bring horses from multiple sources together through February 17th, 2023.

Horses at three private premises and a single equine event/boarding facility have now been diagnosed with EHV-1, with exposed horses on these premises quarantined. In the latest case, the clinical animal was euthanized due to the severity of clinical signs and associated poor prognosis. The animal was boarded at a public facility, prompting the additional actions by the Department.

“We recognize the substantial disruption when an event facility is quarantined, however, previous measures have not stopped additional cases,” said Montana State Veterinarian, Dr. Martin Zaluski.

EHV-1 is a potentially serious disease of horses that can cause respiratory or neurologic disease in affected animals. The neurologic form of disease, equine herpes myeloencephalopathy, is often fatal or leads to euthanasia. The most recent positive case brings the case count to 6 (4 confirmed and 2 suspected) on 4 separate premises. Five of the confirmed and suspected cases have been euthanized. Exposed horses from affected premises are subject to quarantine for 21 days beyond the last date of potential exposure. 

Horse owners who have attended events in the Flathead Valley in recent weeks should monitor their animals for fever (temperature greater than 101.5˚ F) 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 EHV-1 may also have respiratory signs such as cough, nasal discharge, lethargy, and decreased appetite. Horse owners concerned about the health of their horses should contact their local veterinarian. Suspected cases of EHV-1/EHM should be reported to the Department immediately.

The disease is primarily spread through aerosol transmission by inhalation of droplets from coughing and snorting. In several instances, affected horses had no travel history off premises. Instead, herd mates who never exhibited clinical signs attended outside events and appear to be responsible for spreading the virus.

Additionally, the virus can be viable for several weeks in the environment and spread indirectly between horses. Common water sources, feeders, tie-outs, and shared equipment and tack can all contribute to spread. Additionally, people can carry the virus between animals, typically through inadequate washing of hands or equipment. Horse owners should work with their local veterinarians on biosecurity recommendations to help reduce disease spread.

General recommendations for equine travel include:

  • Keep any horses exhibiting signs of disease, including fever, at home.
  • Avoid shared water sources, equipment, tie out locations, and trailering.
  • Consider isolating horses that travel off premises away from their resident population of horses.
  • Horses that have attend events should be monitored for 14 days beyond their last event.
  • If an animal develops a fever, shows signs of respiratory illness, or neurologic disease, please isolate the animal and contact your local veterinarian.

The mission of the Montana Department of Livestock is to control and eradicate animal diseases, prevent the transmission of animal diseases to humans, and to protect the livestock industry from theft and predatory animals. For more information on the Montana Department of Livestock, visit

–Montana Department of Livestock