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Picture of a foal.Equine Herpesvirus Myeloencephalopathy

Equine Herpesvirus Myeloencephalopathy (EHM), a neurological disease of horses caused by Equine Herpesvirus-1 (EHV-1), 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. EHV-1 is not transmissible to humans.

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Equine Herpesvirus Myeloencephalopathy (EHM) - 2015

Monday, June 8, 2015
The quarantine on the Prince William County equine riding school facility has accomplished its purpose and was released on June 6, 2015. No additional horses were found to be EHV-1 positive during the 21 day quarantine/observation period.

Friday, May 29, 2015
All horses at the Prince William County equine riding school facility are being monitored. They remain afebrile and healthy. Also, a subsequent lab report on the index horse that tested as an EHM suspect indicated that the index horse also tested serologically positive for Equine Protzoal Myeloencephalopathy (EPM).

Thursday, May 21, 2015
On May 21, the epidemiological investigation was completed on a farm in Prince William County where a single horse was euthanized May 15 due to neurologic disease, and whose post-mortem test results were reported as suspect-positive for the neurologic strain of Equine Herpesvirus-1. The index horse had not traveled off of the farm recently, and no other horses on the farm have shown any signs of disease. All horses on the farm will continue to be closely monitored for 21 days past the date the index horse was euthanized. Horses will not be permitted to move on or off the farm during this monitoring period.

Friday, March 6, 2015
The Albemarle County equine premises containing 13 horses was released from quarantine following the required 21-day observation period after the index horse was removed from this premises. No horses became febrile or neurologic during this time. The index horse and his stable mate remain in quarantine at a nearby premises and their quarantine release is pending on March 13, 2015.

The Loudoun County farm remains under quarantine with twice a day temperature observations. The index horse remains in quarantine at the Marion DuPont Equine Medical Center. With the exception of that horse, the remaining 34 horses at the farm are pending release on Thursday, March 12.

Wednesday, February 18, 2015
Two horses remain quarantined at the Equine Medical Center and 33 horses are quarantined at the Loudon County farm. No horses have had any neurologic signs.  Two horses under quarantine at the farm have had fevers, and testing for EHV-1 is pending for these horses.

The affected Albemarle County horse continues to improve; no additional horses there have shown any signs of disease.

Friday, February 13, 2015
On February 12, VDACS learned that a horse from Loudoun County had tested positive for the neuropathogenic strain of EHV-1. The horse is quarantined in the isolation unit at the Marion duPont Scott Equine Medical Center (EMC) where it is recovering. A second horse from the same farm exhibited a fever but no neurological signs. As a precaution, it also is in quarantine at the EMC. VDACS began an epidemiological investigation today. Although they have shown no signs, 33 other horses also are quarantined on the farm. See news release here.

The Albemarle County horse continues to improve. No other horses on this premise have been febrile or neurologic.

Monday, February 9, 2015
A VDACS Veterinarian visited the Virginia EHV-1 equine premises again this morning to evaluate the current situation. Even though the index horse continues to drag his rear feet when walking, he is afebrile and is able to gallop. No other horses on the premises have been febrile (fever of 101.5° F) or neurologic.

Thursday, February 5, 2015
VDACS was notified of a positive result for Equine Herpesvirus Myeloencephalopathy (EHM) on a horse displaying neurologic signs in western Albemarle County, Northwest of Charlottesville. The affected horse is located at a boarding stable with 14 other horses at the facility. VDACS contacted the stable manager and placed the facility under quarantine – no horses are allowed to exit or enter the premises until the quarantine is released.

The affected horse is a 14-year-old gelding that showed symptoms on Saturday, January 31, became recumbent on Sunday, February 1, but is now stable. Samples were taken by a private veterinarian and the result was reported to VDACS February 5. An epidemiologic investigation is underway; initial findings indicate that only one exposed horse from the facility has left the premises within the last 14 days, and that horse went out of state.

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


Biosecurity Information for Horses Brochure
Horse Biosecurity Posters
Information from the USDA
Biosecurity Guidelines from the AAEP

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