BELLE FOURCHE — A nationwide outbreak of a common horse virus is getting in the way of some rodeo events in the Black Hills.
Equine Herpesvirus (EHV), a viral infection that can cause death in horses but poses no threat to humans, was recently diagnosed in dozens of horses that attended the National Cutting Horse Association Western National Championship Event in Ogden, Utah, held from April 29 to May 8.
As of June 2, 84 cases of EHV had been confirmed across the U.S. in connection with the cutting horse competition, according to a study from the Animal and Plant Health Inspection Service. Four South Dakota horses went to the competition, but South Dakota State Veterinarian Dustin Oedekoven said none were showing signs of EHV. One horse in Gregory County was diagnosed with EHV-1 in late May, but that horse had not gone to the competition and has since been quarantined to prevent the spread of infection.
Still, some local event groups aren't taking any chances with the virus. Deadwood's all-cowgirl Showdeo, originally scheduled for June 18, was recently postponed because of the virus scare, and a junior high rodeo event at the Seven Down Arenas in Spearfish was also postponed.
Seven Down Arenas employee Sam Martinez said no cases of EHV had been reported, but the event organizers didn't want to risk a possible outbreak at this time, so they postponed it until the virus situation gets a little more under control.
Sandy Bucholz, southwest region secretary for the South Dakota High School Rodeo Association, said the upcoming regional high school rodeo in Sturgis is moving forward as scheduled, with no additional restrictions set for EHV precautions. The Fort Pierre region, however, will require a valid health certificate dated within 72 hours prior to entering the rodeo. Both events are set for Friday through Sunday.
Hank Franzen, of the Powder River Rodeo Company, will be bringing 50-60 head of horses to the upcoming Black Hills Roundup in Belle Fourche, scheduled for July 2-4. Franzen said the virus is definitely something ranchers need to be aware of.
“It's not good,” he said. “Once you get it there's no way to really treat the animal. When (the horses) get it, it's bad - but it's weird. It'll go into a stable and get three horses, and then it's gone and you never see it again. It's not like the whole herd gets it; it might get one, might get three and then it's gone. It's so weird.”
There are nine strains of EHV, with EHV-1 and EHV-4 being the most commonly involved in clinical disease. EHV-1 can cause respiratory disease, abortion in pregnant mares and neurologic disease. In severe cases, an infected horse will die or need to be euthanized because of the symptoms.
Vaccinations and booster shots to protect a horse against EHV are available through local veterinarians, but there is currently no immunization shot that can eliminate the threat entirely.
Franzen said Powder River Rodeo Company has stayed in contact with state veterinarians in South Dakota, Wyoming, Utah and others to make sure they are in full compliance with regulations before bringing their animals to events like the Roundup.
By South Dakota regulation, anyone importing a horse needs to have a valid health certificate for the animal within 30 days prior to crossing the state line, and also negative Coggins test dated within 12 months prior to import. A Coggins test is a sensitive diagnostic test developed in the 1970s for identifying infectious anemia in horses.
Every state has its own set of regulations for horse transportation, including travel permits, temperature readings and veterinarian statements. Keeping up with the regulations can get complicated very quickly, so anyone transporting a horse is encouraged to check with their veterinarians before traveling.
Glen Lammers, the coach for the Black Hills State University Rodeo Team said he and six qualifying student athletes will attend the College National Finals Rodeo June 12-18 in Casper, Wyo.
“The event is still taking place. However, event planners are taking a cautious approach to the situation,” Lammers said.
He said that could change if any more cases are identified.
In the meantime Lammers said everyone involved is taking additional precautions to minimize the risk of any viral outbreaks.
He said each student athlete will be required to take the temperature of their horses for five days prior to attending the event to make sure they don't have a fever. Additionally, they will need to have a veterinarian inspect their horse to verify that they have no symptoms of the virus. During the event, he said student athletes would also make sure there is no nose-to-nose contact.
While the virus should be a concern among horse owners, Franzen said a lot of its actual danger has been somewhat overblown by the amount of news coverage the Utah outbreak has received.
“You have to be cautious, but right now there's just a lot of scare,” he said. “Uncertainty is probably the worst part about it, since a lot of people didn't know about the disease till it went public. But it's sure enough been around for years.”
Dustin Oedekoven, South Dakota state veterinarian, echoed Franzen's appraisal.
“The disease is probably no greater threat now than it has been in the past years,” he said. “I don't think we're facing an increased risk right now. If there is any benefit to the outbreak, it's increased public awareness of the disease and how to prevent and manage (it).”
Elizabeth Boos, associate veterinarian at the Belle Fourche Veterinary Clinic, said there have yet to be any reported cases of EHV in the Hills, but she and her fellow staff aren't taking any chances. Veterinarians at the clinic have been taking temperatures on horses whether the states into which the horses are being moved require it or not, so EHV can be identified before it becomes a bigger problem.
“There were only four horses in state of South Dakota that were in Utah (for the Cutting Horse competition). The risk from that is somewhat low, but the virus is still in the horse herds,” she said.
Most horses are actually exposed to the virus at a young age, she added. Like the human herpes virus that causes cold sores, the virus lies dormant until it is triggered by stress. Also like the human virus, there is no immunization shot that will eliminate it.
To prevent the spread of EHV, Boos and Oedekoven said vaccinations and booster shots are available that will increase a horse's resistance to the disease. Good biosecurity is also effective. Keeping horses isolated at competitions, not sharing water troughs and cleaning horse trailers all help in stopping EHV from infecting other horses.
“Good biosecurity will protect against a lot of diseases beside just the herpes virus,” Boos added.
Oedekoven said the West Nile virus is still around, and cases of Eastern and Western Encephalitis are not uncommon. Good biosecurity will help keep a herd healthy from all such viruses, he said, and he suggested checking with local veterinarians about what options are available for shots and vaccinations.
Heather Murschel contributed to this article.