OLYMPIA – Over the weekend, the equine community in Spokane County was met with unfortunate news as two horses succumbed to the neuropathogenic strain of Equine Herpes Virus (EHV-1) otherwise known as Equine Herpesvirus Myeloencephalopathy (EHM). This contagious, often fatal disease of horses has prompted the Washington State Department of Agriculture veterinarians to issue a warning for those who recently visited a local arena where other horses were present.

Two Spokane equine premises are under official quarantine with veterinary oversight. Horse owners who have commingled horses are encouraged to self-quarantine their horses and refrain from any transportation for the next three weeks to prevent the potential spread of the virus. The arena has closed temporarily to ensure a decreased risk in spreading this deadly virus.

Washington Assistant State Veterinarian, Dr. Ben Smith, emphasized the importance of vigilance during this period, stating, “The virus incubation period is highly variable and can be as long as 14 days.”

Precautionary measures such as isolating newly purchased horses or those returning from shows and seeking veterinary assistance if a horse exhibits a temperature of 101.5 or higher are strongly recommended.

Additionally, practicing good biosecurity measures, such as avoiding nose-to-nose contact between horses and not sharing equipment, is essential to protect all horses in clinics, races, and competitions. It is vital for horse owners and enthusiasts to remain vigilant and cooperative in implementing these protocols to prevent further outbreaks within the equestrian community.

EHV-1 is a common respiratory virus of horses, but the neurologic form causes Equine Herpes Myeloencephalopathy (EHM) that can present with various symptoms, including fever, decreased coordination, hind limb weakness, and lethargy. These signs should not be taken lightly, and immediate veterinary attention is crucial. Taking temperatures twice a day can help with early detection and improve outcomes for exposed or infected horses.

The state veterinarian has approved the use of an experimental immunomodulator drug that has shown promising results to prevent the shedding of EHV-1 virus and protect exposed horses. Horse owners should contact their veterinarian for more information.

Work with your veterinarian to keep your horses up to date on vaccination.  Although there is no vaccine for EHM, EHV-1 vaccines may be cross protective. Horse owners are urged to remain observant and proactive in safeguarding the health and well-being of their animals during this challenging time.

For more information on EHM visit the Equine Disease Communication Center  and the Equine Disease Association for more information on biosecurity.