REGULATORY SERVICES

Equine Herpes Virus-1

Equine rhinopneumonitis virus (EHV-1 or equine abortion virus) is a highly infectious disease that usually affects the respiratory system. Occasionally, the virus may also cause neurological disease. Transmission likely occurs by inhaling infected droplets or ingesting material contaminated by nasal discharges or aborted fetuses. Clinical symptoms may include a fever, difficulty urinating, depression, and stumbling or weakness in the hind limbs. Supportive therapy is often used to treat these cases. In severe cases, horses will be unable to stand; these cases have a very poor prognosis.

Notice to Virginia’s Horse Owners and Accredited Veterinarians Regarding Neurological Equine Herpes Virus -1 in Florida -
March 1, 2013

A horse participating in a horse show in Ocala, Florida, exhibited neurologic signs and tested positive for the Equine Herpesvirus-1 (EHV-1), wild-type strain, on February 20, 2013. Currently, the horse is in stable condition and continues to be treated at the University of Florida.

Some additional exposed horses have also tested positive for EHV-1, although they have not exhibited neurological signs. As a result, there are currently 12 premises under quarantine in Florida. The Virginia Department of Agriculture and Consumer Services (VDACS) encourages Virginia horse owners to be mindful of the situation and to continue to observe strict biosecurity when traveling with their horses. 

VDACS is monitoring the situation in Florida closely and has the following guidance:

• Horses from Florida are not permitted to travel to Virginia if they originate from a quarantined premises in Florida.
• Healthy horses from Florida not under quarantine are able to move from Florida to Virginia at this time on a valid Certificate of Veterinary Inspection or Equine Interstate Event Permit.
• Body temperatures must be recorded on the Certificate of Veterinary Inspection or Equine Interstate Event Permit before travel. Horses with elevated temperatures are not allowed to travel to Virginia.
• Biosecurity is extremely important in reducing the transmission of this disease.  This includes isolation of new positive horses.
• Horse owners and veterinarians may want to bookmark the Florida Department of Agriculture’s website for updates.

VDACS will post updates on the situation here as needed, as well as on its Facebook page and on Twitter.

Equine Herpesvirus Myeloencephalopathy Outbreak Update
An outbreak of Equine Herpes Virus-1 (EHV-1) apparently originated at the National Cutting Horse Association (NCHA) Western National Championships, held April 29 through May 8 in Odgen, Utah. According to a USDA situation report, as of May 19, 2011, a total of 997 horses were reportedly exposed to EHV-1 (either at the NCHA event or through contact with horses exposed at the event); 21 cases of EHV-1 infection and 12 cases of Equine Herpes Virus Myeloencephalopathy (EHM) have been confirmed; and 7 horses died or were euthanized.

To limit the potential spread of EHV-1 and to alleviate horse owners' fears of exposure, a number of events in many states have been postponed or canceled and two veterinary teaching hospitals have closed to non-emergency equine and camelid cases.

The American Association of Equine Practitioners (AAEP) has developed resources about EHV-1, EHM and the current outbreak, including FAQs and resources for horse owners.

Important information about EHV-1:

• Equine herpesvirus myeloencephalopathy (EHM) is caused by equine herpesvirus-1 (EHV-1). The virus most commonly causes respiratory infection, and not all infected horses will develop EHM;
• EHV-1 is a normally occurring virus found in the equine population; this outbreak is not being caused by a new virus or a new strain of a virus;
• Signs of EHM in horses may include nasal discharge, incoordination, weakness of the rear limbs and hind end, lethargy, urine dribbling, and decreased tail tone;
• Llamas and alpacas can also be infected with EHV-1 and may develop neurologic disease;
• Currently, there is no equine vaccine that has a label claim for protection against EHM;
• There is no specific treatment that has been proven effective for EHM;
• If your horse has potentially been exposed to an infected horse (or through contact with people or equipment that have been in contact with an infected horse), or is showing signs that could indicate EHM, quarantine your horse and other potentially exposed horses and contact your veterinarian.

For more information, please refer to AVMA@Work blog post on this subject.