Single EHV-1 Positive Discovered at Keeneland

Following tests of horses quarantined at two Keeneland barns following a positive for equine herpesvirus "wild strain" reported Jan. 21 at Turfway Park, a single horse at the Lexington track tested positive for EHV-1.

According to the Kentucky Office of State Veterinarian, that horse, a 3-year-old male, was removed from the Keeneland barn located near Rice Road to secured isolation. Testing of nasal swabs collected from each horse at that barn is expected to be completed Jan. 25 and horses continue to be confined pending results of that testing.

Testing of samples completed on horses in the second quarantined barn have been reported negative on blood only and they also remain confined to the barn until testing of nasal swabs is complete.

The Keeneland barns were quarantined out of "an abundance of caution," according to Rusty Ford, equine programs manager for the office of Kentucky State Veterinarian, after the horse tested positive for EHV-1 was reported Jan. 21 at Turfway.

The sampling of horses in the affected barn at Turfway did identify two additional horses—a 4-year-old gelding and 9-year-old mare—positive for EHV-1 wild strain following nasal swabs. As of Jan. 24, there were no clinical developments in the horses currently housed in Turfway's Barn 27.

A statement from Ford said biosecurity measures continue at the highest level at each track. The office of the state vet believes that recognizing and responding to the disease risk early in this united manner has been effective at both tracks and provides the opportunity to resolve the disease threat in the coming weeks. 

According to TheHorse.com, there are several equine herpesvirus types and some can cause more damage than others. The type that has dominated headlines recently, EHV-1, can cause respiratory illness, abortion in pregnant mares, congenital infection (foals are born with it, displaying weakness), and sometimes the more severe equine herpesvirus myeloencephalopathy. It's also more common than many people might think. Most horses are latent carriers (not showing signs of active disease) that were infected early in life.

TheHorse.com notes different strains of EHV-1 exist in nature. Researchers have shown in a number of studies that neurologic disease is more frequently associated with EHV-1 strains of a certain mutant genotype rather than the "wild" type (or "normal" strain, which is less likely to cause neurologic disease), but in one survey scientists determined that 14% of all neurologic cases were associated with the wild strains.