The Maryland Department of Agriculture placed investigative "hold orders" on at least 15 locations Feb. 20-23 after a Maryland horse being treated at Leesburg, Virginia's Marion duPont Scott Equine Medical Center (EMC) tested positive for the equine herpesvirus (EHV-1). By the morning of Feb. 23, however, MDA officials said that no horses in Maryland had tested positive for the virus.
The hold orders were reportedly placed on locations in Howard, Baltimore, and Harford counties, as well as multiple facilities in St. Mary's, Montgomery, Carroll and Charles counties. Although additional locations were being evaluated at press time, the investigations centered on horses suspected of having indirect contact with the socalled "index" animal. Th e latter is a horse from St. Mary's County that was reportedly shipped to EMC on Feb. 7 for colic treatment but later developed neurological symptoms, was immediately isolated, and then tested positive for herpes. "The information we have is that the animal lived on the farm and had not traveled recently," said MDA communications director Sue duPont. At press time, the index horse remained at EMC, which was quarantined by the Virginia Department of Agriculture on Feb. 20 after two additional horses being treated there developed fevers and neurological symptoms.
The horses under MDA investigation had been hospitalized at EMC during the same time as the index horse but were discharged before that horse showed signs of herpes. Test results on most of them were expected back by Feb. 26, according to state veterinarian Dr. Guy Hohenhaus.
At press time, the Virginia Department of Agriculture had reportedly placed at least two other Loudoun County locations and one Fauquier County location under quarantine. Th e Virginia state veterinarian had also reportedly ordered the cancellation of all area equine events (including the Casanova Hunt Point-to-Point) for the weekend of Feb. 24/25.
Restrictions & Precautions
As the MDA's duPont explained, a hold order "does the same thing as a quarantine: prevents the movement of horses on or off of the properties until they are lifted. We take this very seriously and our policy is NOT to wait for test results to place a hold order."
She went on to say, "Based on our animal health staff 's visits and evaluations of the farms [and] horses... we feel this is a minimal risk situation." The reasons for this, she said, included the fact that the facilities under investigation were generally small, private farms with a "general lack of movement on and off the farms prior to the hold orders."
Still, the MDA advises horsemen unaff ected by the hold orders to conduct business with a heightened sense of awareness. If preparing to move a horse, question the destination farm and shippers about the health of horses at their facilities or on their vehicles, MDA officials said. In addition, they advise farriers, feed truck operators and other service personnel to ask their clients whether they are under hold orders.
"Always report any signs of illness to a private veterinarian," du-Pont stressed. "With EHV-1, we are particularly interested in fevers over 103 degrees, unexplained respiratory disease, and any neurologic conditions."
Equine herpes is a highly contagious virus that can cause respiratory problems and abortions, but can also take a deadlier neurologic form. It is this form that caused the loss of six horses in Maryland last year; the virus has also struck Florida and Connecticut this winter.