EHV Confirmed in Northern Kentucky Horses

EHV Confirmed in Northern Kentucky Horses

In many horses, fever is the only sign of EHV-1 infection, which can go undetected.

Photo: Alexandra Beckstett, The Horse Managing Editor

The Kentucky State Veterinarian’s Office and the Equine Disease Communication Center have reported that equine herpesvirus-1 (EHV-1) has been confirmed at a Northern Kentucky facility.

A 2-year-old filly residing at an Oldham County facility was brought to an equine hospital in Lexington on Jan. 4 for evaluation of a neurologic condition.

“The examining veterinarian noticed evidence of urine dripping, suspected an infectious disease, and reported the concern to the Kentucky Department of Agriculture (KDA),” the EDCC said. “The filly was isolated and samples were collected which were confirmed positive for the neuropathogenic strain of EHV-1 that same evening”

The KDA placed the filly’s home facility under quarantine.

Subsequently, on Jan. 5, investigators collected nasal and blood samples from 14 horses in the “affected wing,” as well as from three horses in a second wing that were preparing to ship interstate, the EDCC said. Equine Diagnostic Solutions, in Lexington, received those samples on the evening of Jan. 5.

On morning of Jan. 6, the KDA received notice that a horse in the second wing had spiked a fever of more than 103°F. Nasal swabs and whole blood samples were collected and transported to the laboratory. That evening, the laboratory reported that two of the 14 horses sampled from the “affected wing,” as well as the febrile horse from the second wing, were positive for neuropathogenic EHV-1.

“The remaining horses on the premises were sampled with results expected sometime on Monday,” the EDCC said.

The KDA has traced and located all equids that have left the index facility since mid-December, and those horses are being assessed and tested following the agency’s defined protocol. Two horses that left the facility in late December and traveled to a track outside of Kentucky are isolated and samples have been collected and submitted for EHV-1 testing. There has been no movement to any Kentucky racing or training facility.

The State Veterinarian’s office said there is no evidence connecting this event to the recent EHV activity associated with Fair Grounds Race Course in Louisiana.

As of Jan. 7, the index case was reported as improved and was preparing to be discharged from the hospital. When released, the horse will be moved to a private facility and remain in isolation. The positive horses on the index facility have been moved to a designated isolation area.

The EDCC said the horses on the index facility continue to be monitored closely and have their temperatures taken multiple times throughout the day. There have been no fevers or other abnormalities reported as of Jan. 7.

The EDCC said the facility’s management “is cooperating fully and is committed to containing and effectively managing the disease.”

Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy (the neurologic form). In many horses, fever is the only sign of EHV-1 infection, which can go undetected.

In addition to fever, other common signs of EHV-1 infection in young horses include cough, decreased appetite, depression, and a nasal discharge. Pregnant mares typically show no signs of infection before they abort, and abortions usually occur late in gestation (around eight months), but can be earlier. Abortions can occur anywhere from two weeks to several months following infection with EHV-1.

Horses with the neurologic form usually have a fever at the onset of the disease and might show signs of a respiratory infection. A few days later, neurologic signs such as ataxia (incoordination), weakness or paralysis of the fore- and hind limbs, urine retention and dribbling, loss of tail tone, and recumbency (inability to rise) develop.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More