Maryland Alert After Pennsylvania Horse Tests Positive for Equine Herpes Virus

Horse competed in Maryland before becoming ill

On March 31, 2015 the Maryland Department of Agriculture issued a public equine herpes virus (EHV) announcement about a horse from Pennsylvania that had competed in Maryland. After the competition, the Pennsylvania horse tested positive for the virus.

No public announcement from Pennsylvania has been found, so, for your information, the Maryland announcement is posted here in its original language.

Elsewhere, in the country, The Ohio State University College of Veterinary Medicine is reminding horse owners in that state that there have been two recent cases of EHV in Ohio and one in Michigan. One case is responding to treatment as an isolated patient at the Ohio State equine hospital in Columbus.

From Maryland:

A horse from Pennsylvania that appeared in a Maryland horse show on March 15 has tested positive for the equine herpes virus (EHV); however, none of the horses that were in the Maryland show and none of the horses that live with the sick horse in Pennsylvania are currently exhibiting any signs of illness. One horse that was reported to the Maryland Department of Agriculture (MDA) with a fever on March 29 tested negative for EHV.

The horse that is sick did not exhibit any symptoms until March 22 and did not exhibit any signs of illness while in Maryland. The officials of the Maryland show have contacted all trainers of horses in the division that the sick horse was shown in to alert them of the risk and recommend they monitor their horses through April 5, which is the end of the 21 day incubation period for equine herpes.

MDA’s Animal Health Program is monitoring the situation closely. Owners should contact their private veterinarians to arrange for EVH testing if a horse exhibits significant temperature elevations or neurologic signs. Veterinarians are required to report equine neurologic syndrome to MDA.

As of right now, there is no indication that any other horses that had contact with the sick Pennsylvania horse are ill. The Pennsylvania horse is reportedly improving.

Using strict biosecurity measures in day-to-day procedures, even when disease is not suspected, is a key strategy in preventing the introduction and spread of infectious diseases. APHIS Veterinary Services has developed a brochure titled Biosecurity – The Key to Keeping Your Horses Healthy, which can be found at

(end of announcement)

 The announcement can be found at this link and on the website of the United States Eventing Association.




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