Veterinarians suspect the recent deadly outbreaks of equine herpesvirus-1 (EHV-1) in Maryland have subsided. The Maryland Department of Agriculture (MDA) reported EHV-1 outbreaks at two Maryland tracks, a race training facility, and a private sport horse boarding farm in Kent County. The last new neurologic sign of the disease in the state was detected at the Kent County Farm on Feb. 3, and the last new non-neurologic sign (a fever) was logged at Fair Hill Training Center (FHTC) in Cecil County on Feb. 7.

As of March 2, all affected barns had been released from quarantine except for the Kent County farm and one barn each at Pimlico Race Course (in Baltimore), Laurel Park (in Laurel), and FHTC. A notice posted March 1 on the MDA web site stated, “Everything remains quiet with no new indications of EHV-1 at any of the Maryland locations involved. Samples were taken from all 17 horses at the Kent County farm on Monday (Feb. 27).”

Six horses were euthanatized during the Maryland outbreaks.

The EHV-1 organism can cause three different forms of disease, including rhinopneumonitis (“rhino,” a respiratory disease often affecting young horses), abortions, and neurologic disease. The first signs of EHV observed in the current outbreak included unexplained fever and mild to severe ataxia (incoordination)