Neurologic Horse at Maryland Track Positive for Herpesvirus

The Maryland Department of Agriculture (MDA) confirmed today that a 2-year old filly stabled in Barn 1 at Laurel Park has tested presumptive positive for equine herpesvirus type-1 (EHV-1). Results of confirmatory testing from the University of Kentucky are pending. The horse, which was unable to stand yesterday morning, was sitting up and eating this morning with no fever, according to a statement released by the MDA.

"We are working cooperatively with all involved parties using the most up-to-date science and best practices to manage this situation and are doing comprehensive tests to determine the nature of this outbreak," said Maryland State Veterinarian Guy Hohenhaus, DVM. "In the meantime, we urge everyone's diligence in continuing strong preventive measures such as keeping new horses separate from your general barn population for at least one week, disinfecting, and keeping vaccinations up to date."

A hold order has been placed on Barn 1 at the central Maryland track. This restricts all movement into and out of the barn, pending further testing. According to the MDA release, none of the other 29 horses stabled there are showing neurologic signs. Blood samples and nasal swabs on selected horses in barn were collected this morning. Preliminary test results should be available by Friday afternoon.

In January 2006, a filly at Laurel Park was euthanized due to neurologic EHV-1, and at least 11 horses at Pimlico showed clinical signs of the virus.

"Today's news is disappointing but we have already put the proper precautions into place to control the situation," said Maryland Jockey Club racing secretary Georganne Hale. "We learned a great deal from 2006 and now know to shut things down immediately if there is a possible case so as to reduce the possibility of it spreading. The one advantage to having this happen in Barn 1 is that it is already isolated from much of the backside."

Equine herpesvirus causes upper respiratory infection and can lead to severe neurological disease. There is currently no known method to reliably prevent the neurologic form of EHV-1 infection. The MDA recommends maintaining appropriate vaccination procedures to help reduce the incidence of the respiratory form of EHV-1 infection, which might help prevent the neurologic form.

Transmission occurs primarily by direct nose-to-nose contact or contaminated hands, equipment, feed, and water. It can also be spread by airborne droplets. This virus is not associated with any human health risk.

Regular updates regarding this investigation will be available on MDA's Web site  

Read more: "Neurologic Horse Reported at Maryland Track; Hold Order in Place."

See a special report on EHV-1.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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