· January 12, 2012: Two additional horses displaying fever and respiratory signs have been confirmed positive for the neuropathogenic strain of Equine Herpes Virus- 1, on the Orange County Premises. All horses on the premises remain under quarantine and being monitored for disease.

· January 13, 2012: Two additional horses displaying a fever have been confirmed positive for the neuropathogenic strain of Equine Herpes Virus-1. There are a total of five confirmed positive cases on the Orange County premises. All horses on the property continue to be monitored.

· January 18, 2012: Three new cases of neuropathogenic Equine Herpesvirus-1 (EHV-1) have been confirmed on the Orange County quarantined premises. There are a total of 8 confirmed positive horses on the premises. At this point in time, only one of the eight cases has displayed neurologic signs. All exposed horses on the property are being monitored and enhanced biosecurity measures have been implemented. The source of the outbreak has not been identified. The initial epidemiologic investigation reveals no link to the three 2011 California neuropathogenic EHV-1 incidents.

While these cases seem far away in southern California, they remind of the need to constantly observe biosecurity precautions when travelling with our horses or bringing new horses onto a horse property. There is a nice primer covering quarantine and other biosecurity precautions within the Equine Herpes article which appears on the Health Page of this website. Above all avoid nose to nose contact between your horse and outside horses, do not use common water tanks, and if you have touched other horses (especially on the head), wash your hands before handling your horse.

October 5, 2011: Quarantines released on Tuolumne and San
Joaquin County premises.

NO CURRENT OUTBREAKS

Tuolumne EHV-1 Outbreak Updates

September 15, 2011: Seven Confirmed Cases on Tuolumne Premises
Seven of the eight horses displaying compatible clinical signs at the
quarantined premises have been confirmed positive for neuropathogenic
strain of EHV-1. Five of the confirmed cases have displayed neurologic
signs and two of the cases have only demonstrated a fever. One of the
severely affected neurologic confirmed cases has been euthanized. The
initial horse confirmed positive on September 12, 2011 is recovering
on the premises. All confirmed cases are in isolation and all exposed
horses on the quarantined premises continue to be monitored.

September 15, 2011: Two Confirmed Cases on Secondary Exposed Premises
in San Joaquin County

Two horses displaying compatible clinical signs were confirmed
positive for the neuropathogenic strain of EHV-1. These two horses
were exposed to the virus on September 4-10, 2011, while visiting the
Tuolumne county premises. Both horses have been isolated and the
premises has been quarantined. CDFA is conducting an epidemiologic
investigation.

September 14, 2011: Eight horses displaying compatible clinical signs
Eight 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 13, 2011, UCD
veterinary school staff collected samples from 150 animals on the
premises, including the eight 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 in Martinez
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.

LBEMC Editor’s note: The Sonoma County outbreak was quickly
identified and horse movement to and from the premise prohibited.
That outbreak was rapidly quelled and is declared at end. The
Tuolumne County outbreak is complicated by infection discovered in a
large string of pack and saddle horses to which some privately owned
horses were exposed. The large string is now under quarantine and
CDFA is actively tracing the outside horses to their orgin and
isolating them if appropriate. To date, no cases have been traced to
the practice area of LBEMC. The random appearance of this disease is
a good reminder for horse owners and managers of stables and horse
events to review biosecurity precautions recommended in articles
within past items in “Breaking News” or in the Equine Herpes Virus PDF
on the Health page of our website.

“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.

California EHV-1 Causing EHM Disease Update as of 12PM 6/17/11

California has no new confirmed cases of EHV-1. There are a total of 22 confirmed EHV-1/ EHM cases in the state.

The last three positive confirmed horses are located in Glenn County and had a clinical onset date of June 3, 2011.
Fourteen (14) of the confirmed horses have been released from state quarantine.
Eight (8) of the confirmed horses remain under state quarantine in the following counties : Colusa (1), Glenn (6), and Shasta (1).

California Confirmed EHV-1 Cases Summary

• Confirmed Cases – 22
• Counties with Confirmed Cases – 12
• Premises with Confirmed Cases – 14
• Confirmed Horses that died/ euthanized – 2
• Confirmed Cases with neurological signs – 8
• Confirmed Cases with fever only – 13
• Confirmed Cases with respiratory only – 1

New Materials:

EHV-1/EHM Frequently Asked Questions

EHV-1/EHM California Situation Report

EHV-1/EHM CDFA Brochure

UCDavis Center for Equine Health : White Paper on Equine Herpes Myeloencephalopathy (EHM) PDF File (also on the LBEMC Equine Health page)

A rattlesnake vaccine has been available for dogs for at least two years, but this is the first time a vaccine for horses has been made available.  If your horse is located in a high risk area for rattlesnakes, call the clinic and ask to speak with an LBEMC veterinarian about the details.   Also see more details about rattlesnake risk and treatment on the LBEMC website on the Health page.

Download certificates here