News Release from Idaho Equine Hospital regarding the Equine Herpes Virus (EHV-1) outbreak

Posted by on May 14, 2011 in Articles, Bulletins, In The News | 6 comments

Idaho Equine Hospital is participating in an investigation of an outbreak of Equine Herpes Virus 1 (EHV-1) infection in some of our local horses that were exposed at a show in Utah. This outbreak has extended to horses in California, Utah, Colorado, Wyoming, Montana, Washington, and Arizona. Any horse that was at the show in Ogden is potentially exposed.

EHV-1 is a common viral infection of horses that is highly contagious. Symptoms can range from no clinical signs, to mild upper respiratory disease, or abortion. In a small percentage of horses it can cause neurological disorders (weakness or loss of balance unable to urinate or defecate, unable to stand). The highly contagious nature of this disease makes isolation and quarantine of exposed horses critical for containment.

EHV-1 does not affect humans, dogs, cats, cattle, sheep, goats, pigs or birds; although llamas and alpacas (camelids) can be affected.

There have been confirmed EHV 1 cases in horses from the Ogden show at Washington State University and Colorado State University. California has issued a statement concerning the multistate outbreak of EHV 1 associated with this event. Idaho Equine Hospital has seen 2 horses in the treasure valley from the Ogden show with signs of EHV 1. There are also horses exhibiting signs of EHV 1 at other facilities in Idaho. Horses that could have been exposed have been identified and quarantined for observation. Isolation and serial temperatures are the best safety and monitoring guidelines. Vaccination post exposure and the use of anti-viral medication can be considered. Idaho Equine Hospital is working with State Health officials to get accurate information out to all horse owners.

Anyone that has concerns about exposure of their horse should use the following guidelines and contact their veterinarian or state veterinarian for additional precautions:

-Segregate potentially exposed horses from any non exposed horses by at least 50 feet. The exposed horse should not have direct contact with other horses for 3 weeks. Stall cleaning and husbandry practices should be separate for the potentially exposed horses.

-Take your horses temperature rectally twice a day for 21 days. If the temperature is over 102 degrees F please contact us immediately.

- The preferred testing method is PCR analysis performed on a nasal swab. This is only effective to identify horses that are actively shedding the virus.

Idaho Equine Hospital is urging people that may have been exposed at the Ogden show or subsequently to voluntarily isolate and observe those horses. It is in the best interest of all our horses to contain this outbreak if possible. If you have any questions or concerns regarding this matter please feel free to contact one of our veterinarians at 208-466-4613. We will continue to post updates as this situation as it develops.


  1. I have two horses and am concerned about the Equine Herpes Virus. I live in Kuna, Idaho. I do not show or compete with my horses, but wonder there is a vaccine for this virus and if I should give it to my horses. I do trail and pleasure riding.

    Thank you for your time. Linda

  2. Thanks for the great information. We appreciate your detail to information that you share.

  3. Thanks for your question Linda! We ALL need to be concerned. We feel that your best resource for this information would be to contact Idaho Equine Hospital. or 208-466-4613. They will be able to answer your questions. We feel that if we ALL stay home for 30 days we will be able to minimize the contamination from this terrible disease.

  4. My family doctor said this is (rairly) transferable to humans, is this accurate?

  5. Judie,

    This is NEVER transferable to humans as far as we know. Humans CAN transfer the disease to horses with their clothing and hands after working with a contaminated horse.

  6. Hi, I was wondering where I can find out exactly how many horses in Idaho have actually been infected. There are so many rumors running amuck that it is hard to determine. I would like to have the actual facts. We have our arena on lockdown and also our boarding facility. I am getting phone calls every day to see if we have reopened yet.
    Also, what is a realistick time line that I can give people as to when we can safely reopen. Nobody has a crystal ball on that, so that is why I am wanting to know the actual count infected in Idaho and the date of the last horse confirmed with this virus.
    Thank you for any information

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