Two more horses released from EHV-1 quarantine in California

Two Monterey County, Calif., horses that tested positive for a non-neurologic strain of equine herpesvirus-1 (EHV-1) have been released from quarantine, according to an April 4 statement from the California Department of Food and Agriculture (CDFA).

The affected horses had participated in the HITS Horse Show in Thermal, Calif., on March 5-11, 2012, and tested positive for EHV-1 after exhibiting mild neurologic signs after the event. A third horse in San Diego County displayed similar clinical signs after attending the show and also tested positive for EHV-1. That horse had been quarantined and was released last week after resolution of clinical signs and two negative EHV-1 test results, according to the CDFA.

At this time, the CDFA is monitoring a fourth case involving a mare in Los Angeles County that tested positive for EHV-1 on March 30. That horse is currently quarantined and under veterinary care. The CDFA states that the horse may be a secondary exposure to other horses from this facility that attended the HITS Thermal Horse Show in March.

Additionally, four cases of non-neurologic EHV-1 have been reported in Snohomish, Wash., according to the Washington state veterinarian. Three of the affected horses also attended the HITS Thermal Horse Show in March, and the fourth case is believed to be a secondary exposure. All four cases are under quarantine and the facilities are being monitored for further outbreaks.