Vesicular stomatitis has made its appearance once again in Kansas. The virus was first found in Butler County on June 16 and now has been confirmed on more than 30 premises in Butler, Cowley, Sedgwick and Sumner counties. The viral disease primarily affects horses and beef cattle, occasionally swine, sheep, goats, llamas and alpacas, Butler County Extension Agent Charlene Miller said June 25 during a webinar to discuss the disease.
“Butler County would much rather be known for its oil and gas industry,” Miller said. “Unfortunately, we were the first confirmed county in the state to have positive VS cases.”
Miller felt it was important to partner with a couple of agencies to host the webinar to provide factual and timely information regarding the virus.
Justin Smith, state animal health commissioner, Kansas Department of Agriculture, Department of Animal Health, detailed the disease and how his department is working to trace and quarantine animals and premises. The first case of VSV was confirmed in horses in Butler County, Kansas. Kansas became the fourth state in 2020 to have confirmed cases, behind New Mexico, Arizona and Texas. Nebraska was added to the list June 24.
VSV has now been confirmed on a number of premises in Butler, Cowley and Sedgwick counties in Kansas. The most current national situation reports from the U.S. Department of Agriculture Animal and Plant Health Inspection Service can be found at www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/cattle-disease-information/vsv-reports.
As of noon on June 29, according to the Kansas Department of Agriculture, Division of Animal Health, there are 29 total confirmed premises, 23 suspect and pending premises, 52 premises under quarantine and seven released from quarantine.
“Honestly, the size of outbreak that we’re having now is kind of a novel issue here in the state of Kansas,” Smith said. “We haven’t been impacted like we have been so far this year up to this point.”
Smith is taking lessons from many neighboring states, especially Colorado, which had nearly 900 cases for 2019.
VSV is viral disease with two serotypes—Indiana and New Jersey. Smith said there’s a key point to remember.
“They’re indistinguishable as far as the animals concerned, our response is the same no matter what serotype we’re dealing with, and honestly the lesions that you’re going to see on the animals are going to be the same,” he said. “It just so happens this year we’re dealing with the Indiana serotype.”
It’s probably more important to remember how VSV is transmitted. It’s primarily passed through insect vectors—flies, midges, possibly mosquitoes.
Those insects are considered biological vectors, Smith said. “They have the ability to overwinter and then we see this massive hatch that happens out in nature, much like we have this year.”
The virus is passed from parent to the insect larvae. Most of the vectors have what Smith calls “different lifestyles.” Some are nocturnal, while others are active during the day. Some lay larva in the mud, while others like dry areas. Some even use rocky crevices.
“The important thing is we’ve got enough insect vectors here that it’s really hard to manage this virus because these vectors present problems on how do you handle your horses?” Smith said. “Do you stall them at night and let them out during the day? Do you let them out in the night and stall them during the day?”
Choices like this make management problematic because depending on the vector in your particular region, control options could take more care and consideration.
Transmission of VSV can happen a couple of ways, but nose-to-nose contact of animals is the most common way. Next is mechanical. Smith said things like sharing feed and water sources are discouraged when there’s an outbreak.
“Anything that can carry that live virus from horse to horse can be indicated in passing this virus,” he said. “Biosecurity is a huge thing when we talk about this virus and how we can prevent it from moving from horse to horse or from farm to farm.”
VSV primarily affects horses, but it can also be found in other species. For Smith that’s troubling because the blister-like sores are hard to visually distinguish from other diseases—foot-and-mouth disease in particular.
“The only distinguishing characteristic is foot-and-mouth disease doesn’t affect horses,” he said. “But when we get in cattle, sheep, goats and swine, the first thing we have to consider is are we dealing with FMD and we can’t afford to miss that.”
It’s obviously impactful to the animals, and that’s one of the reasons KDA responds the way they do, Smith said. Some clinical signs include:
—Reluctance to eat. This is a pain response mostly because of the blisters in the mouth.
—Drooling or frothing, maybe teeth chomping. Initial response because of pain.
—Lameness. Lesions sometimes appear at coronary band where hoof meets leg.
—Decreased milk production. Lesions are sometimes on the udder and decreased nursing leads to decreased milk production.
—Lesions in ears.
“A lot of that just has to do where that fly tends to be and where we don’t get fly spray typically and get preventative out there,” Smith said. “So where these individual flies will tend to feed on is kind of where some of these lesions may show up.”
Besides the places Smith mentioned earlier, his office has seen some cattle have lesions on their noses. The incubation period is any where from two to eight days. The other thing is, once the lesions show they will excrete viral particles for up to 10 days.
“We don’t see a lot of virus shedding during the incubation period, which is very, very fortunate honestly,” he said. “So most of the viral shedding is once those blisters, once those vesicles come up and break.”
The animal could potentially be shedding for up to 10 days.
“That’s a lot of the reason why we respond the way we do in our quarantines,” Smith said.
Treatment wise, there’s not a lot that can be done to treat VS. It’s mostly supporting care—treatment of the wounds as necessary, anti-inflammatories and antibiotics.
“That’s where you need to have a great relationship with your local veterinarian,” Smith said. “You need to talk about this, and how you can alleviate some of the conditions and secondary infections that these horses might come up with.”
Smith said horses who develop vesicular stomatitis, don’t necessarily develop immunity, and aren’t protected from future infection. And the unfortunate thing is there’s no vaccine to protect animals from VSV.
“We’re finding with these horses, that actually if we’re not doing the right thing as far as fly control and trying to prevent exposure to it [the horse] can become infected multiple times during the same season,” Smith said. “So they do have the ability to become re-infected.”
It is also considered zoonotic, and can be passed from animals to humans. Although transmission is not common, it can still happen.
“But if you happen to have an animal or a horse that is positive for vesicular stomatitis and you are either diagnosing it or you are in the process of trying to treat that, take some precautions,” Smith said.
The lesions will excrete the virus and it provides an opportunity for infection. In humans, the symptoms include influenza-like symptoms, and not as much of the lesions.
“I’ve heard from people that have had vesicular stomatitis. It is a nasty flu-like illness,” Smith said. “It’s more than the flu. They say you’ll run a fever. You’ll have muscle aches, headaches, you just don’t feel good.”
Smith recommends the proper protective equipment—gloves, mask and face shield. Washing thoroughly after handling the animal, including clothing and shoes.
“It’s nothing to be totally fearful of,” he said. “Just with proper precautions, you can protect yourself.”
KDA response
Smith said when his department is responding to an outbreak like VSV, they look at two different things—non-positive counties and positive counties. A non-positive county is one where they haven’t diagnosed a case yet within its borders. If they do get a suspicious case in a non-positive county, that’s called the index case. It must be examined by a Kansas regulatory veterinarian.
“We will go out, we will pull tests and we’ll put you under a suspect and will put you under a quarantine based on clinical signs,” he said. “But then we will send those samples in for laboratory confirmation.”
If the suspect comes back negative, the quarantine is pulled and the premise is back to normal. If it returns a positive, and in the instance of a non-positive county, that now becomes the index case. This does two things.
“One is that allows us to implement some other things that we can leverage our accredited veterinarians that are out there in the field. We can utilize your local veterinarian to help us collect those samples at that point in time,” Smith said. “We will manage at that premises as a suspect until we get lab confirmation.”
The other thing is if the livestock aren’t going to move for 14 days, the premise can be managed as a suspect premises and the animals don’t have to be tested.
“We just assume that you have it based on clinical signs,” he said.
If there’s multiple susceptible species on a premises, they’ll have to come out and do a quarantine release inspection by a veterinarian before the quarantine is released.
“The reason is if you have subsequent animals become infected or start showing clinical signs after that first one, we will have to extend that quarantine out,” Smith said.
KDA has the ability to establish a quarantine, and according to Smith, “there’s some teeth behind it.”
“We know that movement of these horses, movement of these animals that are infected, has the ability to spread that virus,” he said. “We have the opportunity to find that person guilty and it’s up to a level seven non-person felony.”
There are some ramifications of a violation of a quarantine, but Smith and his department hasn’t had any issues with violations. Research has shown the shortening of a quarantine period to 14 days does still create some impact to the facilities. Smith doesn’t anticipate having to cancel events because of VSV this summer and into fall. But if there’s a positive case near by, Smith said to be vigilant.
“If you have a positive on your animal, just increase the vigor of your biosecurity, separate those animals out, do some fly control, do some insect management,” he said. “Common sense—practice some really good biosecurity measures such as washing, disinfecting everything that might come in contact with that positive animal.”
For more information about VSV, visit agriculture.ks.gov/divisions-programs/division-of-animal-health/animal-diseases/vesicular-stomatitis.
Kylene Scott can be reached at 620-227-1804 or [email protected].