EHV-1 Quarantine Lifted in Northern Cal; 3 New Cases at Los Alamitos

Quarantine restrictions at Golden Gate Fields, Bay Meadows and the Alameda County Fair at Pleasanton due to the presence of Equine Herpes Virus-1 were lifted Jan. 10, but three new cases of EHV-1 at Los Alamitos Race Course have been confirmed, according to a California Horse Racing Board advisory.

"There have been no additional clinical cases of (EHV-1) at Golden Gate Fields since the quarantine was established on December 29, 2006," said Dr. Rick Arthur, the CHRB's equine medical director, in the advisory. "The restriction, isolation procedures, and extensive use of PCR testing for EHV-1 among exposed and high-risk horses allowed for the rapid resolution of the quarantine."

Under the quarantine, horses could be transferred between Golden Gate in Albany, Bay Meadows in San Mateo and Pleasanton, but no horse could leave any of the tracks except to travel to another quarantined track.

Horses could enter the three tracks from another facility, but they were then subject to quarantine conditions. Racing continued as scheduled at Golden Gate.

Arthur credited Dr. David Wilson, the University of California-Davis' large animal clinic's director, his colleagues and students, as well as Dr. Diane Isbell, the morning association veterinarian at Golden Gate Fields, for their work on the EHV-1 control program and close monitoring of horses during the quarantine. Dr. Joan Hurley was the CHRB's Official Veterinarian.

"Horsemen are encouraged to continue prudent hygiene practices and to check the temperature on all horses twice a day," Arthur said.

At Los Alamitos, Arthur said the three clinical cases are confined to one barn. Similar restrictions and testing protocol are now in place there that were employed at the Golden Gate previously.
 
The CHRB has scheduled educational seminars on EHV-1 for owners and trainers at Santa Anita on Jan. 16 and at Golden Gate Fields on Jan. 17. Wilson and Dr. John Madigan from the equine medical staff at UC Davis will be the main speakers.

Last year, similar outbreaks affected tracks in New Jersey, Maryland and Kentucky.

The equine herpes virus strain produces flu-like symptoms such as upper respiratory infections and a high fever. In severe cases, it can attack a horse's nervous system and affect coordination and balance and can lead to the horse being euthanized. It does not affect humans. It is transmitted through contact between horses, similar to a human cold.