EHV-1 Case Leads to Maryland, Virginia Restrictions; NYRA Imposes Ban

By Erin Ryder
A confirmed case of neurologic equine herpesvirus-1 (EHV-1) at an equine hospital in Leesburg, Va., has resulted in numerous hold orders at farms in Maryland and Virginia as horses released from the hospital after being exposed to the sick horse are tracked back to their home farms.

"All the horses that are still here are now quarantined and isolated," said Dr. Nat White, director of the affected hospital, Virginia Tech's Marion duPont Scott Equine Medical Center. "Horses that were discharged before we knew what the situation was have gone back to their farms. The state veterinarians in both Maryland and Virginia are contacting those farms and making a decision about quarantining and or monitoring."

Although there are no suspected positive cases in Maryland, state officials there have placed 13 facilities under investigational hold orders, restricting equine movement onto or off the property.

Ten private facilities in three Virginia counties have also been quarantined. According to the Virginia Department of Agriculture, these restrictions cover approximately 175 horses.

Meanwhile, the New York Racing Association joined the list of tracks placing restrictions on entry of horses from some states in the Mid-Atlantic region.

NYRA announced Feb. 24 that horses from Virginia, West Virginia, Maryland, and Delaware would be denied entry to any NYRA track until further notice. That action followed similar steps taken previously by Charles Town in West Virginia, which banned entry of any horses that had been in Virginia or Maryland since Feb. 1, and by Penn National in Pennsylvania.

Three horses at the equine medical center in Leesburg, Va., have shown neurologic signs consistent with EHV-1 and are in isolation. The entire hospital has been quarantined with 15 horses remaining at the facility. No new patients will be admitted until officials release all of the horses. This is the first time the center has been quarantined since it opened in 1984.

According to White, the index case was admitted to the hospital in early February for colic surgery. This horse recovered in the hospital for several days before exhibiting a fever, at which time it was immediately isolated from other horses.

EHV-1 is a strain of herpesvirus that can cause respiratory disease, abortions, fevers, and neurologic signs that range from incoordination and weakness in the hind limbs to paralysis.