The horse community is on high alert due to an outbreak of a contagious and potentially deadly equine virus that has prompted regulatory and industry organizations to institute quarantines and travel restrictions in Arizona and other western states.
The Arizona Department of Agriculture confirmed the first case of Equine Herpes Virus (EHV-1) in an Arizona horse on May 17. The horse was exhibiting symptoms of severe neurological disease, adding to the numerous recent reports of EHV-1 among horse owners across the U.S. and Canada.
“In an outbreak of EHV-1 neurologic such as we are experiencing now, the disease can reach high morbidity and case fatality rates,” said William Moyer, president of the American Association of Equine Practitioners.
To date, one horse fatality and three confirmed cases of EHV-1 have been reported in Arizona.
EHV-1 is a highly contagious airborne virus that spreads quickly among horses, but is not dangerous to humans.
According to the United States Department of Agriculture (USDA), the current outbreak can be traced to horses attending the National Cutting Horse Association (NCHA) Western National Championship event held April 29-May 8 in Ogden, Utah.
A report issued by USDA on May 19 indicated 21 Arizona horses were exposed at the Ogden event, with 67 Arizona horses secondarily exposed.
Dr. John Hunt, Arizona’s state veterinarian, said that all of the horses and premises in Arizona known to have been exposed through the Ogden event are under close observation, and as of press time, no new cases of neurological disease have been observed.
The incubation period after exposure to EHV-1 is one to two days, with fever then setting in. Neurologic symptoms typically manifest eight to 12 days after exposure.
Early symptoms of the virus can mimic many other illnesses, explained Dr. Abbie Reidhead, owner of Holbrook Veterinary Clinic. It’s when horses begin to exhibit neurologic symptoms, indicating that the horse has the more serious neurological form of the virus, that horses may begin a rapid decline.
Reidhead encourages horse owners to promptly seek medical advice if their animals show symptoms such as runny nose, lack of appetite and fever.
More serious symptoms include poor coordination, hind end weakness, lethargy and urine dribbling.
There is not a vaccine or a specific treatment for EHV-1, although antiviral drugs may be of some help prior to neurological symptoms setting in. Anti-inflammatory drugs are also widely recommended.
“Memorial Day weekend is one of the biggest horse event weekends of the year and kind of kicks off the rodeo season, but we’re encouraging people not to take their horses anywhere,” said Reidhead.
Her advice is echoed by regulatory and industry organizations across the country, with Hunt emphasizing that it’s at events where horses are brought together from different places that the virus is more likely to spread. In response to the outbreak, several horse-related events in Arizona have been cancelled and some horse parks have temporarily closed.
Locally, the Navajo County Fairgrounds is responding to biosecurity guidelines that call for a 21-day quarantine of all horses in boarding facilities, directing facility managers to not let boarded horses leave the premises until the quarantine, which is currently in effect until June 10, is lifted.
“We can’t let the horses that are already here leave the area, and we can’t receive overnight travelers unless owners have written clearance from a vet, dated no more than two days prior, that says their horses do not have the virus,” said Leia Barbea-Haro, secretary at the Navajo County Fairgrounds.
Reidhead said that the situation needs more monitoring before it can be said for sure when quarantines will be lifted and the danger declared over.
“The Department of Agriculture needs more time to determine where all the confirmed cases are and how the outbreak is spreading before it can say when the health alert will be lifted,” she noted.
Reidhead explained that owners aren’t likely to find the virus among their horses if they haven’t traveled recently or allowed other horses to visit their premises.
As of press time, she had not seen any cases among her patients, nor had she heard of any cases in the area.
“Keeping your horses home is the best bet until the outbreak passes,” Reidhead concluded. “It’s not worth losing your horse over one rodeo. ”
Resource: AZ Journal