The death toll over a serious equine virus at Los Alamitos grew to 12, with five more horses euthanized after an outbreak of equine infectious anemia (EIA) in the barn of quarter horse hall of fame trainer Heath Taylor.

The first horse that was infected and euthanized was Bullet Train V on Sept. 24, according to the California Horse Racing Board website. Then six more horses were euthanized Oct. 2 and 3. All were quarter horses, meaning they wouldn’t be racing at Santa Anita or Del Mar. The five who were euthanized Wednesday also were quarter horses.

There were six other deaths among Taylor’s horses reported at Lone Star Park in Texas. There are six other horses in the Taylor barn who are under quarantine but have not tested positive for the virus and will be monitored.

If a horse tests positive for EIA, they can be quarantined for life or euthanized. It is costly to keep the horse limited to quarantine alive.

“After EIA was detected among Taylor horses in other states as well, CDFA (California Department of Food and Agriculture) and United States Department of Agriculture initiated epidemiological tracing of the disease,” the California Horse Racing Board said in a statement. “As such, all of Taylor’s horses at Los Alamitos were tested by CDFA. Those tests identified two additional positives in the Taylor barn, resulting in their euthanasia. The other horses tested by CDFA have tested negative but six remain in quarantine. The six are identified as ‘close contacts’ while in another state.”

Taylor is considered one of the sport’s most prestigious trainers, having won almost 2,000 races from about 9,000 starts. In an interview with the Paulick Report, Taylor said he was “absolutely devastated” by the deaths.

Los Alamitos, which runs almost year-round, has had an abnormal amount of fatalities. The track also has had five musculoskeletal deaths this month.

This outbreak has put more scrutiny on horse racing in Southern California. The sport is languishing locally, with lower attendance, mutuel handle and foal crop (number of horses born).