Seven quarter horses have been euthanized at Los Alamitos Race Course following an outbreak of a potentially fatal infectious virus, according to state officials.
The California Horse Racing Board, which oversees the state’s racetracks, was notified of the first case of equine infectious anemia on Sept. 24.
The California Department of Food and Agriculture is monitoring the ongoing investigation at Los Alamitos, officials said in a CHRB advisory posted Thursday, Oct. 3.
“Under the order of the CDFA and dictated by state and federal standards, that first infected horse was euthanized and the biosecurity measures were put in place,” the advisory states. “Nine additional horses were placed in a quarantined cohort group and subsequent testing identified six additional confirmed positives.”
Those six additional horses were subsequently euthanized on Wednesday and Thursday, according to the advisory. All of the euthanized horses belonged to the same trainer, Heath Taylor, according to the CHRB.
The other three horses, which tested negative, will remain quarantined and must be retested in 60 days.
Equine infectious anemia is a virus in the same category as HIV, feline immunodeficiency virus (FIV) and bovine immunodeficiency virus (BIV) and persists in the animal’s white blood cells, according to the CDFA. The virus can be spread by biting flies and contaminated needles. There is no cure and an infected horse that survives an infection becomes a lifelong carrier.
Due to the infectious nature, horses with EIA must be euthanized, or quarantined at least 200 yards from other horses for the rest of their lives under USDA rules.
The CDFA is attempting to trace the virus’ origin at Los Alamitos and believes, at this time, that the transmission likely happened during a medical treatment prior to the first horse arriving in California.
There have been several EIA outbreaks in Southern California in recent years. In March, two quarter horses were euthanized and 10 others were quarantined until testing negative in Los Angeles County.
An outbreak originating in San Bernardino County in January 2022 led to the euthanization of eight quarter horses and the quarantining of 11 more.
