Additional horses at Keeneland Race Course’s Rice Road Training Center has tested positive for equine herpesvirus-1 (EHV-1), the State Veterinarian’s Office confirmed in an update late on Jan. 26.

“Testing of samples collected on Jan. 25 from horses in both barns (at Keeneland’s Rice Road Training Center) has been completed and … did identify a second positive horse in the first barn, bringing the total EHV-1 ‘wild strain’ positive horses in that barn to two,” said E.S. “Rusty” Ford, equine programs manager for the Kentucky State Veterinarian’s Office. “This most recent horse (from the first barn), a 3-year-old Thoroughbred colt was positive on nasal swab, negative on blood. The colt was moved from the barn to the secured isolation last night (Wednesday, Jan. 25).”

Also at the Rice Road Training Center, Ford said, “testing of horses in the second barn did identify three horses—all are 2-year-old Thoroughbred fillies—to be EHV-1-wild strain-positive by PCR from the nasal swabs. Testing of whole blood samples from each horse did not detect evidence of EHV-1. These additional positive horses were moved from the barn to secured isolation earlier tonight.”

Ford said both quarantined barns remain secured with high-level biosecurity protocols in place, and with access restricted to essential personnel only.

“In addition to the affected barns, heightened biosecurity has been implemented in the entire barn area that includes directing and restricting entrance into each barn, as well as requiring disinfecting upon entry and exit of each barn,” he said.

“Designated times have been established for the horses from the quarantined barns to gain access to the track for exercise following the normal training hours and after the general population of horses having returned to their barns,” he added.

Ford also provided updates on three other Kentucky premises at which horses tested positive for EHV-1.

Turfway Park—“The two positive horses identified … on 1/24/17 were moved offsite and are securely isolated on a private farm,” Ford said. “Monitoring of the general population (at Turfway) continues with no evidence of further cases developing. The previously established and described protocols for ship-ins, racing, training and monitoring remains in effect.”

Oldham County Premises 1—Ford said exposed horses residing at this premises—which was first quarantined on Jan. 5 after a filly was diagnosed with EHV—were tested again this week.

“Testing of the barn’s population of horses that had been exposed to EHV-1 was completed (Jan. 25) with each horse testing negative on both nasal swabs and whole blood,” he said. “Having been greater than 14 days post-exposure and each horse now having two negative sets (nasal and blood) of (test) results, the Kentucky Office of State Veterinarian has released the quarantine … and the horses are under no further restrictions.”

Oldham County Premises 2—The second Oldham County facility—quarantined Jan. 12 in an unrelated EHV outbreak—remains under quarantine, Ford said.

“Daily monitoring and assessment of the horses in the exposed quarantine barn continues with no evidence of further transmission of EHV-1,” he said. “Collection of samples (swabs and blood) from these horses has been scheduled to be completed next week to determine their eligibility to be released from restrictions, as well.”

[brightcove videoid="3027535698001" title="Health Alert: Equine Herpesvirus"]

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.