September 13, 2011: Nine (9) horses displaying compatible clinical signs
Nine additional horses displaying compatible clinical signs are in isolation at the facility and are awaiting confirmatory test results from nasal swabs and blood collected yesterday. The initial confirmed positive mare has shown improvements and has been moved back to the quarantined premises in Tuolumne County for recovery. Epidemiologic investigation is ongoing and the premises owner and CDFA have contacted owners of potentially exposed horses that visited the affected premises over the past two weeks. On September 14, 2011, UCD veterinary school staff collected samples from 150 animals on the premises, including the nine (9) demonstrating compatible clinical signs. Test results are anticipated within the next few days. CDFA will continue to monitor the situation.

·         Potential Exposure to EHV-1 at the September 10, 2011 ACTHA Ride for Mustangs
A horse participating in this ride was exposed to the positive confirmed case on the Tuolumne County premises.  The exposure occurred prior to the ride and the exposed horse has not displayed any signs of disease. However, out of an abundance of caution, CDFA has contacted all ride participants to recommend isolation and temperature monitoring of horses which participated in the ride for 14 days from the last exposure. A temperature greater than 102F or other compatible clinical signs should be reported to a veterinarian who can collect samples for diagnostic testing.

September 13, 2011: New EHV-1 Case
On September 12, 2011, a mare from Tuolumne County has been confirmed positive for the neuropathogenic strain of Equine Herpes Virus-1. The mare is isolated, quarantined and undergoing treatment at a veterinary referral hospital. The premises of origin have been quarantined and the potentially exposed animals on the premises are being monitored. A full epidemiologic investigation at the affected premises has been initiated by CDFA Animal Health Branch field personnel. CDFA will continue to monitor the situation and provide updates as the situation warrants.

Sonoma County September 2011 Outbreak
September 13, 2011: Quarantine Release
On August 23, 2011, a 15-year-old Oldenburg mare from Sonoma County was confirmed positive for the neuropathogenic strain of Equine Herpes Virus-1. Two (2) additional horses on the affected premises were confirmed positive by nasal swab for the neuropathogenic strain of EHV-1. The only clinical sign displayed by these two horses was a fever. Epidemiologic investigation conducted by CDFA reveals minimal disease risk based on lack of animal movement on and off the affected premises. The affected premises were quarantined and the thirteen (13) other horses on the property were temperature monitored twice daily and observed for clinical signs for 21 days. No additional horses have demonstrated a fever or any other compatible clinical signs. On September 13, 2011, the quarantine was released.

May 2011 Outbreak
The National Cutting Horse Association (NCHA) Western National Championship held in Ogden, Utah April 30-May 8, 2011 had 400 competitors. On May 13, 2011, California Animal Health Officials were notified by the NCHA that fifty-four (54) California horses that competed in the event may have been exposed to the neuropathogenic strain of the EHV-1 virus. Some of these same horses were entered in the Kern County Cutting Horse event in Bakersfield, CA on May 13, 2011. One horse, that competed in Ogden, UT, was euthanized at the Kern County Cutting Horse event after showing severe neurological signs; EHM was the final diagnosis for this horse. All horses at the Ogden, UT and Bakersfield, CA events were potentially exposed to the disease. A total of 22 California horses were confirmed positive for the neuropathogenic strain of EHV-1. On June 20, 2011, California declared containment of the EHV-1 Outbreak.

 

Additional information at the California Department of Food and Agriculture website.

http://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html