Vesicular Stomatitis Virus Outbreak Affects Oklahoma Producers

I wrote this feature story for my agricultural communications classes at OSU.

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As you walk to the barn to feed your show steer, you notice he hasn’t eaten well since he came back from the show last weekend. Concerned, you start looking over your calf to see what is wrong.

After closer inspection, you discover blisters in his mouth and call the veterinarian. The

vet comes out right away, takes a swab of the blister, and tells you he thinks it is vesicular

stomatitis virus, but he needs to test the fluid to be sure.

VSV most commonly affects horses, but it also can affect other species including cattle, sheep, goats, swine and llamas, said Dr. Rod Hall, the Oklahoma Department of Agriculture, Food and Forestry state veterinarian.

“The symptoms of [the virus] are typically vesicular lesions, and that’s how it got its

name,” Hall said. “Vesicular means vesicle or blister-like lesions and stomatitis indicates the

inflammation of the mouth and the lips.”

Vesicle lesions also can occur around the ears and between hooves, Hall said.

“It can be spread directly from one animal to another, but more typically it is spread

through vectors, like flies, gnats and biting midges,” Hall said.

Once a client notices the lesions on an animal, the animal needs to be tested because virus is hard to diagnose by physical examination the animal, Hall said. To diagnose VSV, vesicular fluid or tissue around the lesions must be swabbed and tested, Hall said.

“Many times, the vesicles have already ruptured and are more of an erosive-type lesion

by the time clients notice it,” Hall said.

No vaccination exists to treat VSV, and Hall added he doesn’t know if one will be

developed, Hall said.

“Because it is considered to be a foreign animal disease, it is highly unlikely even if there was a vaccine it would be approved for use in the United States,” Hall said.

The virus causes animals to go off of feed for a few days but is not fatal, Hall said. After

an animal is diagnosed, the virus must run its course, since no medication exists to treat the

disease, Hall said. While this disease is not common in the U.S., producers can take steps to prevent their animals from contracting the virus, he added.

“Good vector control to prevent the flies, midges and the gnats from getting around the

livestock is the best way of preventing it,” Hall said.

In addition to vector control, biosecurity is also important if clients take their animals off

the farm, said Donna Patterson, the Rogers County agriculture extension educator.

“Any time you have an animal disease, [preventing] it comes back to good biosecurity,” Patterson said. “When your animal has been away from the farm, quarantine it for 14 days. If there is something [the animal] contracted, [then] they aren’t spreading it to the entire farm.”

If someone touches an animal, the individual needs to wash and sanitize their hands

before touching other animals to prevent the spread from animal to animal, Patterson added.

This year’s outbreak resulted in statewide travel and health certificate requirements, Hall said. This has only been the second outbreak of VSV Hall has seen since he assumed his role in 2006, he added.

“This summer, we started seeing multiple cases up in the northeastern part of the state,”

Hall said. “We felt like it was important to put those movement restrictions in place this summer.

"It's not something we would do unless we felt like there was a definite need for it given

the particular situation,” Hall added.

The reason for this year’s outbreak has not been determined, but some theories for the

severity exist, Hall said.

One theory is infected insects from Colorado’s outbreak last year laid eggs in the Arkansas River, he said. These eggs floated down the river and hatched near Tulsa, which is where the concentration of cases were this summer, Hall said.

The outbreak of the virus raised several questions for producers and communication with them was important during this time, Patterson said.

“My role and how I used my position in the VSV outbreak was basically the flow of

information,” Patterson said.

This included explaining travel restrictions to producers, working with the county fair

board to develop safety protocols for their livestock shows, and communicating with state

officials, Patterson said.

Rogers County was one of nine counties in Oklahoma with confirmed VSV cases,

according to a report released on Sept. 3 by the U.S. Department of Agriculture. A total of 22 confirmed cases were reported across the state, according to the report.

The restrictions in place to prevent the spread of the virus meant producers had added

time and expenses to attend livestock events, said Katsy Rohrbough, a horse trainer and barrel racer from Collinsville, Oklahoma.

“Health papers are normally current for 30 days, but because of VSV spreading so

rapidly, the Oklahoma Department of Ag[riculture] said they were only good for five days, so

you had to go back to the vet every five days,” Rohrbough said.

If she was going to more than one event in a weekend, she had to have multiple health

certificates for the same animal since health papers are location specific, Rohrbough said.

Even with the risk of her animals contracting VSV, Rohrbough said she wasn’t worried

about going to events while active cases were in the state because she practices biosecurity.

“I was only worried about the irresponsibility of other livestock owners who didn’t care

whether or not their animals contracted VSV or not,” Rohrbough said.

Many events were already canceled due to COVID-19, which likely helped keep case

numbers low, Patterson said.

No events canceled specifically because of VSV, Patterson said. The possibility was

discussed when planning the Tulsa State Fair horse show and the county fair, she added.

The VSV outbreak appears to be over for the year, but the risk isn’t gone until the entire

state has a hard freeze to kill all of the vectors, Hall said.

“We haven’t actually had a confirmed positive case since the end of July,” Hall said. “We removed all of the movement restrictions back in the middle of September.

"I think we are probably done with it for this year, but there is still some potential we

could see a few more cases,” Hall said.

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