Montana Department of Livestock recommends extension of cancellation Flathead County horse events

5 horses in the Flathead euthanized due to Equine Herpes Virus
Horse virus
Posted at 2:56 PM, Feb 07, 2023
and last updated 2023-02-08 10:40:31-05

HELENA - The Montana Department of Livestock (DOL) has quarantined a horse event-boarding facility after Equine Herpes Virus 1 (EHV-1) was discovered.

The DOL has quarantined the facility and is extending the recommendation for limiting travel and canceling events in the Flathead Valley that bring horses from multiple sources together through Feb. 17, 2023, according to a news release.

The animal was euthanized in the latest case due to the severity of clinical signs and associated poor prognosis. DOL also notes the animal was boarded at a public facility, which prompted the additional actions.
“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 the disease, equine herpes myeloencephalopathy, is often fatal or leads to euthanasia.

DOL states the most recent positive case brings the case count to six (four confirmed and two suspected) at four 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.

DOL advises 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 Montana Department of Livestock 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. DOL advises that horse owners 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 attended 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. 

Additional information about the Montana Department of Livestock can be found at