by US Equestrian Communications Department | Feb 25, 2022, 6:09 PM EST

Lexington, Ky - In conjunction with the California Department of Food and Agriculture (CDFA), USEF has created the following FAQ to provide our members with up to date information regarding the EHV-1 outbreak. The responses below are based on information available to USEF at the time of distribution. The situation in California is fluid. USEF will provide updates as additional information becomes available.

1. What is Equine Herpes Virus?
   Equine Herpes Virus-1 (EHV-1) is a virus that is present in the environment and found in most horses all over the world. Horses are typically exposed to the virus at a young age with no serious side effects.
   

2. Are there different strains of EHV-1?
   There are two strains of EHV-1:

   1. The wild-type (aka non-neuropathogenic) strain; and

   2. The mutant-type (aka neuropathogenic) strain of EHV-1.
      
      It is important to note that neurologic symptoms have been identified with both strains of the virus.
      

3. What is Equine Herpes Myeloencephalopathy (EHM)?
   EHM is the neurological disease syndrome caused by the EHV-1. In this syndrome, the EHV-1 virus damages blood vessels in the brain and spinal cord causing the various neurologic clinical signs.
   

4. How does the disease spread?
   EHV-1 is spread by direct horse-to-horse contact. The virus may also be spread indirectly through contact with objects contaminated with the virus, such as clothing, human hands, equipment, tack, trailers, feed, water buckets, and wash rags. The virus can become airborne but only for short distances.
   

5. How many horses have tested positive for EHV-1 that were on the grounds at DIHP or associated with horses that had been on the grounds of DIHP?
   To date, 18 horses have confirmed positive for EHV-1. Some of these horses tested positive after leaving DIHP.
   

6. How many horses have tested positive for EHM that were on the grounds at DIHP?
   To date, three (3) horses from DIHP have confirmed positive for EHM (EHV-1 infection with neurological signs). One of these horses had to be euthanized.
   

7. Is there a relationship between DIHP and the euthanized horse that competed at LAEC?
   At this time, there is no known direct link between the DIHP and the euthanized horse confirmed positive for EHM (EHV-1 infection with neurological signs) that competed at LAEC.
   

8. Did horses leave DIHP and within 7 days compete at LAEC against LAEC’s protocols?
   We have reports that 4 horses left DIHP and within 7 days competed at LAEC against their protocols. Those horses were removed when this became known to management. USEF is investigating these reports.
   

9. Is there a relationship between DIHP and the euthanized horse in San Juan Capistrano?
   The euthanized horse in San Juan Capistrano confirmed positive for EHM (EHV-1 infection with neurological signs) had not been to DIHP, but was exposed to other horses upon their return from DIHP. One of the returned horses confirmed positive for EHV-1.
   

10. Where can I find up-to-date information this?
    Updates on confirmed cases are reported on the California Department of Food and Agriculture and Equine Disease Communication Center websites. Please do not rely on information from social media or word of mouth.