Nine cases of equine herpes virus have been detected this month at a property in Orange County. When the article below was written, the number of confirmed cases was fewer.
By Paula Parisi January 17, 2012
The five cases of EHV-1 diagnosed Jan. 11-15 in Orange County, CA, have been contained, according to sources close to the situation.
Although the California Department of Food and Agriculture has not given the official “all clear,” animal health branch chief Dr. Kent Fowler confirmed that the five cases were identified at a single facility and all affected horses have been quarantined. Movement to and from the facility has been halted except in emergency situations (for which a special permit must be obtained).
EHV-1 is a strain of Equine Herpes Virus. In its most serious form, neuropathogenic EHV, it can be fatal, but most forms produce only cold/flu-like symptoms. There are specific tests to determine whether an animal has neuropathic EHV-1. Of those who do, only a fraction suffer serious impairment or death.
Of the five current cases of neuropathogenic EHV-1 identified in San Juan Capistrano, only one is exhibiting neurological symptoms.
The Langer Equestrian Group’s Los Angeles Equestrian Center Opener horse show will go on as planned Jan. 20-22 in Burbank, CA. The Blenheim EquiSports Winter Classic show, which was scheduled Jan. 13-15 in San Juan Capistrano, was cancelled due to the proximity of the outbreak, which occurred at a private barn in the area.
California had an EHV-1 outbreak last year marked by three separate cases that resulted in 22 confirmed instances of neuropathogenic EHV-1, documented May through September, taking a devastating toll on the horse show business.
“This wasn’t like last year, [where the outreak] started at a show [in Utah] and spread when everyone went home,” LEG CEO Larry Langer said. “These horses never set foot out of their stalls.” Langer lauded BES president Robert Ridland for putting safety first and cancelling his show “as a precaution.”
Ridland said he was in Cincinnati attending the United States Equestrian Federation’s annual meeting when his wife, Hillary, heard EHV-1 had been detected locally. She contacted their barn manager, Lorraine Tathum, and BES show veterinarian Dr. Richard Markell, who was able to get confirmation that the CDFA had quarantined a nearby facility. The next morning, Jan. 11, Markell and BES show manager Stephanie Wheeler conferred and made the decision to cancel the weekend show.
“It was a 15 minute conversation,” Ridland recalled. “Even though there was no evidence any of the exposed horses had left their facility or would be coming to our show, Richard advised that the most responsible thing would be to cancel, so we did.”
Only 12 hours earlier Ridland had participated in a discussion with USEF president David O’Connor about implementing a national first alert system that would allow for rapid, accurate and efficient communiqués to disseminate vital health information.
“The idea would be for all 50 state veterinarians to have a hotline to the USEF, so when things like this happen, they can quickly look across all disciplines to see what shows might be affected, because showing and traveling horses are the most common way that this virus spreads.” The disease can be transmitted by touch ― not only equine-to-equine, but also human-to-equine and canine-to-equine. The most common transmission, however, is through shared water and feed sources, Fowler noted.
Ridland said he saw to it that every trainer scheduled to attend the Winter Classic received a personal phone call alerting them to the situation, but explained that BES purposely did not post notice on the BES website or blast it out via email, “because we felt might cause a panic. Often these situations are handled correctly but the panic gets out of hand. A system like the USEF is proposing would go a long way toward minimizing the health and economic exposure we as an industry face in situations like this.”
Prior to 2011, the last case on record in the state originated in 2006 and lingered into early 2007.
Fowler said U.S. data indicates there have been more cases of EHV-1 in the past 10 years than in the 30 prior, but that it is unclear whether this is because there are more outbreaks or because diagnostic tools have improved. It was only last year that the CDFA put neuropathogenic EHV-1 on the mandatory reporting list for labs. “Emergency conditions must be reported in the first 24 hours. EHV-1 falls into the second category, regulatory reporting, which is the first 48 hours. We moved it up from the third category, monitored reporting, which means they need to submit data on a monthly basis. Part of the reason we made that change is because we saw an increase in cases while becoming aware of how effective early intervention was in preventing spread of the disease.”
Ridland considers the industry lucky that this outbreak occurred in January – a slow month for horse shows – rather than in February, when things start heating up for the spring season and the HITS Desert Circuit in Thermal, CA.
The CDFA’s Fowler advised that concerned horse owners look for symptoms including a fever, cough, nasal discharge, listlessness or swelling in the lower limbs . In the more severe case of neuropathogenic impairment, horses appear imbalanced and lose motor coordination.
“The virus is always present in the equine community, but is mainly dormant, the way people carry the virus for cold sores,” Los Angeles equine vet Dr. Bruce Ramey said. “For virologists it’s a non-event. Occasionally a horse will have a very serious reaction and that’s what scares everyone. In fact, a minority of the horses develop neurological signs.”
Fowler recommends common sense vigilance. “If you have any possibility of exposure, we recommend taking the temperature twice a day, and if it’s up above 101.5 notify your private veterinarian.” There are nasal swab t and blood tests used to definitively diagnose the disease. While there are no “labeled vaccines” for the neuropathogenic strain of EHV-1, experts feel that some of the commercially available high-antigenic vaccines can offer protective benefits.
“That is something people should talk to their private vet about, getting on a good herd health program,” Fowler said.
If no new cases are diagnosed 21 days after the last reported incident the CDFA will release the quarantine.
For updates, visit www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html.