Photo Courtesy of Wisconsin Equine Clinic

March 6, 2013 – According to a local veterinarian, two horses were euthanatized Monday after developing fevers on Friday and subsequently developing neurologic signs. They were found to be PCR positive for Herpes. Several other horses (6-7) at the same barn, Double W in Gurnee, IL, have developed fevers and neurologic signs and are under medical treatment. No other barns are affected at this time. The State Veterinarian has quarantined the barn.

The State Veterinarian, Dr. Mark Ernst, placed the quarantine because of the size of the farm. No other quarantine is in effect and there are no changes in requirements for horses entering or leaving the state at this time.

Two horses from the barn attended a clinic at Sunflower Farm in Bristol, but over three weeks ago according to manager Phil May. The two horses that attended have tested negative for the virus. “As a precaution,” said May, “we are monitoring all horses for the next ten days and taking daily temperatures. All temperatures are within normal ranges at this time.” 

The attending clinic, Bristol Veterinary Services, made this statement today:

Once again the neurological variant of Equine Herpes Virus Type 1 (EHV-1) has shown its ugly head. As of early March, 2013 multiple cases of EHV-1, including two deaths , have been confirmed at one location in Lake County, Illinois. The media is concurrently reporting positive cases in Florida. At this point in time, we have only confirmed information on one stable and that facility is under quarantine. Bio-security procedures have been implemented to contain the potential spread from this stable. As you can imagine, episodes like this are fluid and the information flow changes rapidly between fact, speculation, and rumor while waiting for test results and response to treatment. As this situation evolves, we at Bristol Veterinary Service will continue to provide updates and additional recommendations if warranted.

Bristol veterinarian, Steve Graham, DVM, indicated that they did not know the source of the virus and may never be able to pinpoint a source.  This outbreak has no relation to the Florida outbreaks at this time. 

Pat Boyle of Showplace Productions, has cancelled the Ledges A Horse Show for this weekend as a precaution. Next weekend will go on as planned. They have established biosecurity measures including requiring horses arriving in the area or returning to the area from Florida to layover at a location outside Florida for at least 10 days and have fresh Health Certificates issued before arriving at the competition.

All horses arriving on the show grounds must have a health certificate issued within the last 7 days and a current negative Coggins test is required for all horses arriving from outside Illinois.

Dr. Chuck Johnson of Wisconsin Equine Clinic stated, “The EHV-1 outbreak in Florida has raised several questions from our clients regarding vaccinations.  We at WECH in conjunction with the American Association of Equine Practitioners and the American College of Veterinary Internal Medicine recommend vaccination with an EHV (Rhino) vaccine two times a year.  

I personally feel there is some cross protection from the current vaccines even though they are not specifically labeled for the neurologic form.  This was evident after the outbreak of EVH during the horse show in Utah in 2011, the exposed horses I saw that had been vaccinated showed no fever or clinical signs.  One of these included a gelding that had shared a bit with the first clinical case.

As always we recommend sound biosecurity protocols. I have attached two links that provide more information from the AAEP.”

EHMEHV1FAQ2013.pdf              EquineHerpesvirusFinal022513.pdf

The outbreak seems to be a confined outbreak with horses not involved in the hunter/jumper community. ChicagoEquestrian.com will keep everyone posted if there is any additional information available.