The Blood-Horse and The Horse have learned that three barns at Churchill Downs have been put under quarantine because of a possible outbreak of an equine viral respiratory disease. Rusty Ford of the Kentucky State Veterinarian’s Office confirmed Tuesday night an “indication” of equine herpesvirus as the reason for the quarantine and said he was awaiting test results Wednesday morning that could determine the presence of the disease.

Ford did not say whether any of the barns under quarantine contained horses scheduled to ship to Pimlico racecourse in Baltimore, Md., for Saturday’s Preakness (gr. I) or other stakes run there this weekend. Three planeloads of horses were scheduled to leave Louisville, Ky., Wednesday morning. Included in those shipments is Kentucky Derby (gr. I) winner Giacomo. Ford also did not say whether the presence of equine herpesvirus in horses at barns under quarantine would affect shipping to Maryland of horses from other barns stabled at Churchill Downs.

According to veterinarian Nancy S. Loving, writing in the June 2005 issue of The Horse magazine, Equine herpesvirus is classified into five different strains. EHV-1 and EHV-4 are the strains associated with viral respiratory disease. EHV-1 is the most prevalent concern in horse populations not only because its respiratory disease is more virulent than that caused by EHV-4, but also because it can lead to viral abortion in mares or neurologic disease.

Fever and an upper respiratory infection are the most common signs of EHV-1. Infected horses may show signs of lethargy, poor appetite, nasal discharge, and a cough. An infected horse can spread the virus up to 35 feet, with a cough or snort. The virus is short-lived and susceptible to disinfectants.

Detection of EHV-1 in three horses at Turfway Park in 2003 just days before that track’s major event, the Lane’s End Stakes (gr. II), did not disrupt the race, though track officials took several precautionary steps to ensure the health of the horses at the Northern Kentucky track.

The Turfway incident involved just one barn, which was put under quarantine for 21 days. Horses shipped in to the track during that period were housed only in the receiving barn or stakes barn, and all stalls in those barns were stripped and thoroughly sanitized.

In January and February of 2003, an outbreak of EHV-1 at the University of Findlay in Ohio led to the death of 12 horses. In a separate outbreak, two horses were euthanized as a result of EHV-1 at Penn National racecourse in Pennsylvania.

More information on equine herpesvirus:
Equine Herpesviruses 1 & 4
All TheHorse.com articles on equine herpesvirus