UPDATED: Virus Outbreak Infects 11 Local Horses

EDITOR'S NOTE: Latest update today says two more horses with fevers have tested positive, bringing the total to 11. 

State officials have confirmed 11 cases of a contagious and deadly equine virus at a San Juan Capistrano equestrian center.

The disease, Equine Herpes Virus-1, poses no risk to humans. But it may have already claimed the life of one local horse. 

According to the California Department of Food and Agriculture, the outbreak began last week when a gelding started displaying signs of the neuropathogenic strain of the virus.

The state agency would not identify the stable, but local equine veterinarian Janice M. Posnikoff said it was .

Posnikoff attended a meeting held at Stone Field today, hosted by state animal health officials to answer any questions the equestrian community had. At first, she could really feel the anxiety among the crowd.

But. Dr. Kent Fowler, animal health branch chief at the Food & Agriculture agency, handled the meeting "expertly," Posnikoff said.

"As soon as he started answering questions, I could feel all the tension really ease up," she said.

About 100 people attended the meeting. 

• See video of the meeting here.

That first gelding was quarantined Jan. 11, and the equestrian center was not allowed to move horses on or off the property.

“A full epidemiologic investigation at the affected premises has been initiated by the CDFA Animal Health Branch,” reports the state agency's website.

Two more horses displayed signs of the virus the next day, according to the state agency. A total of nine cases have been confirmed.

Equine Herpes Virus-1, or EHV-1, is a serious disease involving inflammation of small blood vessels in the spinal cord and/or brain. It can be airborne and transmitted by touch, close contact between horses or by sharing feed, brushes, bits and other equipment, according to a press release from the city.

Symptoms include fever, sneezing, staggering and partial paralysis. Horses with symptoms should be isolated and kept 40 feet or more from other horses. Owners should contact their veterinarian, according to the city.

On Wednesday, one of the positive-testing horses which initially displayed a fever and swelling of the legs became recumbent and the decision was made to euthanize this horse, the state reported. A necropsy, an autopsy for an animal, is scheduled.

The last outbreak of Equine Herpes Virus-1 in California occurred in September in Tuolumne County. The state said there was no connection between those cases or a multistate outbreak earlier in the year and the new outbreak in San Juan Capistrano.

Each time a new horse is confirmed positive, the state places it in a 21-day quarantine, the city press release states. Owners and handlers do have access to the unnamed equestrian center.

The time between an initial EHV-1 infection of the respiratory tract and the onset of neurological signs is about eight to 12 days, according to the city. The neurological symptoms appear suddenly and reach peak intensity within 48 hours.

The key to disease control is the immediate separation and isolation of identified suspect cases. The city is asking residents who have contact with horses to take these precautions:

• Do not work with healthy horses after caring for a sick horse – people can easily transmit this virus on their hands and clothing
• Wash your hands thoroughly with soap and hot water between contacts with horses to reduce risks of disease spread
• Wear disposable gloves and change them between horses or use hand sanitizers between contact with horses
• Thoroughly clean and disinfect boots and footwear between entry into barns and stalls to help minimize the spread of disease

Currently, no vaccine exists to protect horses, according to the state. Animal health officials suggest infected horses be treated with intravenous fluids, anti-inflammatory drugs, anti-viral drugs and other supportive measures.

Posnikoff has several clients with horses at Rancho Sierra Vista, but so far, they are infection-free. She has been keeping her clients and horse trainers updated by email.

She's confident word is spreading throughout South County, especially in communities that have concentrations of horse enthusiasts, such as Coto de Caza and Lake Forest.

"Because this disease has happened in other parts of the state and country, the information has gotten out," Posnikoff said.