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Equine virus: Wyo vets say EHV-1 poses no long-term threat

by Wyoming Livestock Roundup

Over the past couple weeks, members of the horse industry in the West have been concerned about Equine Herpes Virus, but Wyoming’s health officials say it won’t have a long-term affect on this summer’s horse events.

The most recent outbreak of the virus surfaced after the National Cutting Horse Association (NCHA) Western National Championships in Ogden, Utah in early May. When the disease was discovered after the competition the NCHA notified state animal health officials, and those officials then contacted owners of potentially affected horses.

There are two main strains of the virus that have come out of the Utah event. The first is Equine Herpes Virus (EVH-1), the respiratory form of the virus, and the second is Equine Herpes Virus Myeloencephalopathy (EHM), which is the neurologic strand.

Symptoms of the strains are abortions in mares, especially late in the pregnancy, and runny noses, high temperatures, loss of tail tone and bladder control and, in extreme stages, the animals can lose control of its limbs. The virus is transmitted through respiratory discharge or even saliva, either through direct contact or through the air.

Of the 308 horses that were directly exposed in Ogden, there have only been 21 confirmed cases of the EVH-1 strand and 12 confirmed cases of EHM. Of the horses exposed, seven horses have died or have been euthanized.

“As of this week there have been no confirmed cases or suspect cases found in Wyoming,” says Wyoming State Veterinarian Jim Logan.

Following first word of the outbreak, and subsequent precautions taken in states surrounding Wyoming, much concern about the virus’s effects on summer equine events arose after with the cancelation of the high school rodeo in Casper scheduled for May 21 and 22.

Despite that cancelation, the rest of the high school rodeo season looks to be a go, says Dixie Huxtable of the Wyoming High School Rodeo Association (WHSRA).

“We deal with horse viruses all the time, it’s not anything new. Yes, it is something that we want to take care of, but we’ve dealt with West Nile and a variety of other diseases over the years. We will just continue to monitor it and do the best that we can,” says Huxtable.

According to Logan, 10 states had confirmed cases of the Equine Herpes Virus, and that led to concern and rumors over the upcoming College National Finals Rodeo (CNFR), scheduled to take place in Casper June 11-18.  

“You can hear rumors, you can hear anything you want to hear. As far as I’m concerned, this is absolutely no different in any respect, form or fashion to the CNFR than the outbreak we had in 2007 in the south,” says CNFRVeterinarian Don Cobb of Casper. “We went ahead and had the CNFR, there was no problem.”

However, additional safety precautions are being implemented for the CNFR this year, in addition to the customary health inspections to prevent the spread of any disease.

“As for the horses coming in for the CNFR, we are requiring a vet inspection within the 72 hours prior to arriving in Casper. There is the possibility that we will be using some fairly sophisticated equipment to determine horse temperatures upon arrival, as well,” says Logan.

“The EHV-1 outbreak has attracted much attention throughout the country, but it’s something that shouldn’t necessarily send up the red flag on traveling or confinement. This outbreak of herpes isn’t anything new to the horse industry,” says Cobb.

“If you were to take test samples from 100 head of horses, between 75 and 80 of them would test positive for a herpes virus. Once they get herpes, they always have it. The herpes virus lays dormant, and when you put the horses under stress such as traveling long distances and competing in rodeo or horse shows, the virus acts up,” added Cobb.

With any outbreak comes fear, but Cobb says the fear and panic that this epidemic has sparked, and the media attention it has received, might be slightly overblown.

“To put this into perspective, the only thing that I can compare this degree of panic that is associated with this is the same degree of panic that Orson Wells produced when he went on the radio and broadcasted the War of the Worlds,” jokes Cobb. “The reaction to this has been absurd.”

Nevertheless, horse owners should take caution if traveling with their horses. Logan suggests keeping horses isolated, monitoring their temperatures and ensuring that their temperatures don’t get above 101 degrees. He also suggests looking out for runny noses and anything that may appear to be paralysis of the limbs.

Tressa Lawrence is an editorial intern for the Wyoming Livestock Roundup and can be reached at

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