Here are the current updates from the CDFA website:

Riverside County Incident

Background: On January 25, 2012, a large, multi-discipline facility in Riverside County was quarantined after a horse displaying neurologic signs was confirmed positive for Equine Herpes Virus -1 (EHV-1).

• To date, only one positive confirmed case on this premises and that horse was euthanized on Monday, January 23, 2012.
• Exposed horses are monitored and temperatures are taken twice daily.
• Owners of exposed horses which left the property prior to the quarantine have been contacted and asked to isolate, monitor for signs, and take exposed horse temperature twice daily.
• Epidemiologic investigation reveals no link to any previous CA EHV-1 incidents
• CDFA continues to monitor the situation

Orange County Incident

Background: On January 11, 2012, a large, multi-discipline facility in Orange County was quarantined after a horse displaying neurologic signs was confirmed positive for Equine Herpes Virus-1 (EHV-1)

• To date, a total of 16 horses have been confirmed positive for EHV-1.
• Only one horse has displayed neurologic signs and all others displayed compatible clinical signs such as fever, nasal discharge, and/or limb edema.
• The initial neurologic horse is recovering and has subsequently tested negative on two sets of samples.
• The last clinical onset date of a confirmed positive case was January 24, 2012.
• All infected horses are isolated and enhanced biosecurity measures implemented.
• Exposed horses are monitored and temperatures are taken twice daily.
• Owners of exposed horses which left the property prior to the quarantine have been contacted and asked to isolate, monitor for signs, and take exposed horse temperature twice daily.
• Epidemiologic investigation reveals no link to any previous CA EHV-1 incidents.
• CDFA continues to monitor the situation.

Recommendations for Participants at Horse Events

CDFA Animal Health Officials continually monitor the Equine Herpes Virus-1 situation.  Currently, CDFA is not aware of any transmission from the quarantine premises to any other premises or group of horses.  Based on the current status of the EHV-1 situation, CDFA has not made any recommendations for the cancellation of any equine events.  Horse owners traveling to an equine event are reminded that there is always risk when horses of unknown health status are commingled at one location for a show or competition.  CDFA strongly recommends horse owners practice proper biosecurity when traveling to or stalled at an equine event.  Consistent basic biosecurity practices play an important role in reducing risk of exposure to all contagious equine diseases when attending an event.  The following basic biosecurity measures should be followed at horse events to decrease potential disease spread:

• Limit horse-to-horse contact.
• Limit horse-to-human-to-horse contact.
• Avoid use of communal water sources.
• Avoid sharing of equipment unless thoroughly cleaned and disinfected between uses.
• Monitor your horse for clinical signs of disease and report any temperature over 102F to your veterinarian.

A gelding displaying hind limb incoordination and urine dribbling from Empire Polo Club, a Riverside County premises, was confirmed positive for the neuropathogenic strain of Equine Herpes Virus-1 (NEHV-1). The gelding became recumbent and was euthanized. The premises is under quarantine and CDFA has initiated an epidemiologic investigation. At this time the CDFA (California Department of Food and Agriculture) is not aware of any links to the Orange County incident.

As of today, January 26, 2012, there are no new EHV-1 cases on the Riverside County quarantined large multi-discipline equine premises.

In order for a horse to become infected with EHV-1 he/she must be in direct contact with the infected horse and/or the nasal discharge.

For excellent information on EHV-1 and the quarantine process, please click here.

For full details on this outbreak as well as the Orange County outbreak, both of which are confined to their respective stables, please click here for the CDFA website.

There are 5 new cases in the outbreak of Equine Herpes Virus-1 (EHV-1) in Orange County at Rancho Sierra Vista Stable in San Juan Capistrano. A total of 16 Neuropathogenic Equine Herpes Virus -1 (NEHV-1) positive cases have been confirmed at the quarantined Orange County premises. Only the initial confirmed positive horse displayed neurologic signs and he is currently recovering. All other confirmed NEHV-1 positive horses displayed respiratory symptoms, limb edema and/ or fever. A confirmed positive horse became recumbent and was euthanized on January 18, 2012; the necropsy results indicate that it is highly unlikely that the recumbency was due to the NEHV-1 infection. The single premises remains under quarantine and CDFA continues to monitor the situation.

The large multi-discipline facility has been quarantined with no movement of horses on or off the property. The potentially exposed horses on the premises are being monitored. A full epidemiologic investigation at the affected premises has been initiated by the CDFA Animal Health Branch.

In order for a horse to become infected with EHV-1 he/she must be in direct contact with the infected horse and/or the nasal discharge. All of the horses currently infected, are located on the Orange County facility and there has been “no movement of horses on or off the property”.

For information about EHV-1 from AAEP (American Association of Equine Practitioners) click here.

For information about EHV-1 from UC Davis, click here.

For all the details of this outbreak and the previous three outbreaks in California, click here.

For the BioSecurity Basics Brochure, click here.

The next time you see Dr. Catt.  Ask him to take your picture.  You might show up in one of his photos.

“I want to thank California’s horse owners and veterinarians for their prompt and thorough actions to isolate and monitor exposed animals and contain this outbreak of EHV-1,” said State Veterinarian Dr. Annette Whiteford. “We also owe the success of this project in part to the outstanding isolation biosecurity measures implemented by horse facility managers, show/event managers and other professionals who work with and care for horses.”

It is important that the California horse owners remain vigilant as there is always risk of disease when horses of unknown health status are commingled at one location. Consistent, basic biosecurity practices play an important role in reducing risk of exposure to diseases such as influenza, strangles, pigeon fever, or equine herpes virus.

By implementing the biosecurity measures below, you can minimize disease risk:

• Minimize horse nose-to-nose contact with horses of unknown disease status.
• Don’t share equipment including buckets, tack and grooming equipment.
• Avoid using communal water troughs.
• Fill water buckets directly from the faucet to eliminate potential hose contamination.
• Limit human contact between horses or wash hands or use hand sanitizer between horse contacts.
• Prior to returning home from an event, clean and disinfect all equipment, including trailer, clothing, tack grooming supplies.
• Isolate all new horses or horses returning home for a minimum of three weeks. Isolation means no direct  contact with other horses or humans and no indirect contact via shared equipment.
• Consult your veterinarian to establish appropriate vaccination for your horse(s).

Horse owners are strongly encouraged to consult their veterinarian regarding these steps and others to determine how best to reduce the risk of your horse acquiring an infectious disease.

(Following this Fact Sheet are several links for up to date information about the EHV-1 virus outbreak in California and general facts about the disease.)

A recent disease outbreak of Equine Herpes Myeloencephalopathy (EHV-1) has been traced to horses who attended the National Cutting Horse Associations’ Western National Championships in Odgen, Utah on April 30 – May 8, 2011. California horses who participated in this event may have been exposed to this EHV-1 virus.

The California Department of Food and Agriculture encourages owners of horses who participated in the Odgen, Utah event to isolate and monitor their horses for clinical signs of disease. A rectal temperature in excess of 102F commonly precedes other clinical signs. Therefore, we are urging owners to take temperatures on each individual horse(s) twice a day. If a temperature above 102F is detected contact your private practitioner immediately. Laboratory submission of nasal swabs and blood samples collected from the exposed horse can be utilized for virus detection and isolation.

The EHV-1 organism spreads quickly from horse to horse and the neurologic form of the virus can reach high morbidity (illness) and mortality (death) rates. The incubation period of EHV-1 is typically 2-10 days. In horses infected with the neurologic strain of EHV-1, clinical signs may include: fever, nasal discharge, incoordination, hind end weakness, recumbency, lethargy, urine dribbling and diminished tail tone. Prognosis depends on severity of signs and the period of recumbency. There is no specific treatment for EHV-1. Treatment may include intravenous fluids, anti-inflammatory drugs and other appropriate supportive treatment.

Currently, there is no equine vaccine that has a label claim for protection against the neurological strain of the virus.

The strain of EHV-1 causing neurological symptoms is a mutation of the EHV-1 virus most often associated with abortion in pregnant mares. There is NO vaccine for this strain. The commonly used 5-way or Flu/Rhino vaccine has EHV-1 antigens (the sensors that alert the body to produce antibodies to a specific disease) in the vaccine but the “load” of antigens is too low for protection in horses challenged by the virus. However, the Pneumobort-K vaccine and Rhinomune vaccine have a high antigen “load” against EHV-1, but still does not protect against the mutated strain of EHV-1. There is some thought that giving the Pneumobort-K vaccine or Rhinomune vaccine with a high “load” of EHV-1 antigen may be of benefit, but this is purely antidotal, and there is no research to support this protocol. Information suggest that both vaccines create similar immune response to EHV-1, however neither vaccine create direct protection to the mutated strain of EHV-1.

The disease is a virus and requires direct contact from horse to horse, or perhaps more commonly owners are contaminating their hands, and then contaminating others horses. Also, the virus can be airborne and transmitted as an aerosol to other horses. Common sense regarding direct contact with other horses should be used.

Horse-to-horse contact, aerosol transmission, and contaminated hands, equipment, tack, and feed all play a role in disease spread. However, horses with severe clinical signs of neurological EHV-1 illness are thought to have large viral loads in their blood and nasal secretions and therefore, present the greatest danger for spreading the disease. Immediate separation and isolation of identified suspect cases and implementation of appropriate management measures (contact your veterinarian for proper management, if you suspect you have a neurological EHV-1 horse) are key elements for disease control.

CONCLUSION: Monitor your horses for illness and/or neurological symptoms. Avoid contact with horses that you may suspect have had contact with the disease, and wash your hands between horses that you are not familiar with. Common sense and contacting your veterinarian if you have symptoms or concerns is the best approach. We encourage you to contact your veterinarian with specific questions.

California Department of Food and Agriculture Daily Update

UCDavis Center for Equine Health White Paper on EHM

EHM Owner Update

EHV-1/EHM FAQ’s

USDA Resources

USDA Equine Herpes Myeloencephalopathy Brochure

American Association of Equine Practitioners Fact Sheet

TheHorse.com Equine Herpesvirus-1 Myeloencephalitis (EHV-1/EHM) Resources

CDFA Equine Herpes Myeloencephalopathy Fact Sheet

USDA Biosecurity Brochure

Link to United States Veterinarian’s Directory

National Cutting Horse Association Website

Basic BioSecurity Brochure