10/26/2007 12:00AM

Churchill barn quarantined due to herpesvirus

EmailLOUISVILLE, Ky. - The Kentucky Department of Agriculture quarantined barn 47 at Churchill Downs on Friday after a horse trained by David Carroll tested positive for equine herpesvirus (EHV1), a contagious, potentially fatal disease that can cause upper respiratory problems and loss of coordination.

Carroll said the horse, a 3-year-old he declined to identify, began showing neurological problems Thursday and was shipped to Hagyard Equine Medical Institute in Lexington. Tests taken revealed the presence of the virus Thursday evening. He said the horse is "going to be fine, make a complete recovery."

The quarantine order - which confines horses stabled in barn 47 and prohibits them from being shipped, trained, or raced - affects approximately 35 horses, split between two trainers, Carroll and Al Stall Jr. A separate division of Carroll-trained horses at Churchill Downs Trackside are not under quarantine.

Horses trained by Carroll and Stall were scratched at Keeneland on Friday and others were to be scratched over the weekend.

Rusty Ford, the equine programs manager for the office of Kentucky State Veterinarian Dr. Robert Stout, DVM, said the implementation of the quarantine was ordered in an effort to contain and isolate any possible equine herpevirus cases to that barn and prevent any spread of the virus. Biosecurity measures have been added for the Churchill Downs fall meet, which begins Sunday, including restricting horses that ship in to race to the track's receiving and stakes barns. Disinfecting procedures also have been increased at the receiving and stakes barns, starting gate, and paddock.

Test results "suggest to us that we are dealing with an animal that has a low level of the virus in its system, and that works to our advantage," Ford said. "If that is the case, the infected horse would present a lesser risk of transmission of the virus to other horses in the barn or the general horse population."

The disease can be spread through the air when a horse coughs, although studies indicate that it is short-lived and susceptible to disinfectants. It poses no danger to humans. The recommended quarantine period is generally as many as 21 days after potential exposure. That period could be reduced if test results show a milder, neurological strain, not a mutant strain of the virus, Stout said.

The discovery of this latest case of equine herpesvirus comes 2 1/2 years after it was last found at Churchill Downs in May 2005. At that time, three barns were quarantined, and it immediately affected the shipping and racing of some horses that had been expected to go from Churchill Downs to Pimlico to race in Preakness-week stakes.

Cases of the equine herpesvirus have increased at racetracks in recent years, which Stout attributes to the spread of the mutant strain of the virus. Since the 2005 Churchill Downs equine herpesvirus outbreak, Calder Race Course, Turfway Park, Pimlico, The Meadowlands, Golden Gate, and Bay Meadows have had cases of horses testing positive for the virus.

During past discoveries of the equine herpesvirus in Kentucky, quarantined horses were allowed to train - separate from the general horse population - approximately a week after the start of the quarantine.