In the last few days, three horses in California have been confirmed positive for Equine Herpes Virus (EHV-1.) The first horse was part of a group of 15 warmbloods that were imported from Germany through the USDA Animal Import facility in New York. This horse was shipped to Lexington, Kentucky via Tennessee, and from there flew to Ontario airport in San Bernardino County, California. The horse was taken to Del Mar, where he soon began exhibiting symptoms, including a high fever and ataxia of the hind limbs. He died within 72 hours of his arrival. Along with the horses that perished in Florida, this brings the total number of EHV-1 deaths to six.
Because the sick horse was transported along with other horses while he was in a highly contagious state, California horsemen are worried about the possibility of a larger outbreak. So far, two yearlings shipped with the sick horse and brought to the Fresno area have been confirmed positive for EHV-1. Both are doing well as of this writing. Several other California horses that shared travel accommodations with the gelding that died are reportedly exhibiting fevers. So far, none is seriously ill. (Read more about it here.) In addition, a mare that shipped with the gelding from New York to Kentucky has been declare healthy and released from quarantine.
Equine rhinovirus is not a reportable disease in California, which means (among other things) that all quarantines there are voluntary. Since the winter season in California (like the winter season in Florida) is a time when many horses are moving to different competition venues, there is the possibility of a serious outbreak. Officials at various horse hot spots (such as El Dorado Polo Club) are asking those shipping in to take extra precautions to ensure that they do not introduce infected horses to the local population.