Equine Herpes Virus-1 (EHV-1) Outbreak Information

20 cases of the disease have been reported nationally with 6 horses dying (or being euthanized) in US and 1 in Canada.  The states affected include Colorado, California, Washington, and Idaho and most likely several others.  The source of the outbreak remains a mystery.  Initial reports that a Canadian horse euthanized at the Ogden event was the index case are almost certainly false as he was confirmed to suffer from a different condition and was euthanized at the request of the owner (and tested negative for EHV-1).

A horse reportedly affected in southwestern Montana is also believed to be *negative*. (Updated 5/18/2011)  For the most current information, use links below.

General Information

http://www.aphis.usda.gov/vs/nahss/equine/ehv/equine_herpesvirus_brochure_2009.pdf

http://www.useventing.com/safety.php?id=2788

Montana information

http://liv.mt.gov/

Specific Control Measures

http://www.aaep.org/pdfs/control_guidelines/Equine%20Herpes%20Virus.pdf

Biosecurity Guidelines following potential exposure

Vaccination
Booster vaccination of healthy animals in primary and secondary contagion control perimeter may have some value, and is not known to lead to complications. If animals are unvaccinated prior to the outbreak there is unlikely to be time to administer an effective vaccination series during the risk period.

If your horse has been on Headwaters Veterinary's vaccination protocol, an intranasal vaccination is available which can provide a potentially rapid booster.  EHV protection is short lived, so frequent booster vaccination (every 2 months) is recommended for horses traveling to events.

General biosecurity

Quarantine possible affected horses for 28 days following potential exposure.  No direct contact.  No shared water or equipment.

Take horses temperature twice daily.  If temp exceeds 102 F call your veterinarian.

Clinically normal horses housed within the primary perimeter may be permitted segregated exercise periods outside the perimeter. Precautions should be taken, and may include:

Exercise scheduled after general population’s exercise period to avoid potential
virus transfer to unaffected horses/barns by exercise riders

Access to starting gate or similar equipment denied

Restricted use of ponies/outriders’ horses—horses housed within the primary perimeter may only be escorted by horses housed within the same facility.

Direct horse-to-horse contact is to be avoided.

Prompt post-contact use of hand sanitizer by individuals having contact with horses during
exercise

Biosecurity Issues for Receiving Animals

Horses having been housed within primary perimeter:

Isolate from general population for 28 days

Horses having been housed within secondary biosecurity perimeter:

After having determined its level of risk-aversion, the recipient facility may consider the following:

Vaccination requirements for entrance into facility

Update vaccination for animals at recipient facility before arrival of potentiallyinfected/exposed animal.