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Vesicular Stomatitis Outbreak!

Vesicular Stomatitis, or VS, is a viral disease that primarily affects horses and cattle. It may occasionally affect other hooved animals, such as pigs, goats, sheep, llamas, and alpacas. Rarely, humans handling affected animals can experience flu-like symptoms. Although rarely fatal, VS can have a personal and economic impact on livestock owners.

I decided to write a blog about this because apparently, outbreaks have already started this summer. On June 15th, I received an email from the Kansas State Veterinary Diagnostic Lab that Arizona, New Mexico, and Texas had confirmed cases of VS in horses. Two days later, a second email added Kansas to that list.

In the United States, horses appear to be more affected than cattle. In 2014, Colorado, Nebraska, and Texas reported more than 400 VS-positive equine facilities. Between April 2015 and March 2016, another 823 premises were affected in 8 states (Arizona, Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, and Wyoming). That year-long outbreak was the worst recorded incident of recent years.

How Might VS Impact You and Your Plans?

Before I describe the virus and the symptoms, how might this reportable disease impact you? For one thing, you should be aware of what states are experiencing outbreaks. It is critical that you travel with health papers. This outbreak might affect where you can travel. Cattle producers experience loss of revenue when affected animals don’t eat well or require veterinary care. Horse owners lose riding time, experience veterinary bills, and worry a great deal about their uncomfortable animals.

Colorado experienced a VS outbreak last year. In the past, I had been able to trailer my horses to the livery in Rocky Mountain National Park, as I knew the owners and had ridden with them in past summers. It was a great place to park my trailer and have access to different trails. Due to the VS outbreak, my friends had closed the herd and were not allowing contact with outside horses. Thus far, Colorado doesn’t have any cases, but I wonder how long that will last?

Symptoms of VS

VS causes blisters and sores in the mouth, tongue, and muzzle, around the coronary bands, ears, and sometimes teats and sheaths. Usually, the area most often affected is the muzzle, tongue, and mucus membranes of the mouth. This causes excess salivation and, of course, difficulty eating. Loss of appetite, weight loss, and lameness are common symptoms. The first thing a horse owner is likely to notice is excessive salivation and drooling.

Researchers believe the location of the lesions has a great deal to do with the feeding preferences of the insect vectors that carry this disease. VS can be directly transmitted (from horse to horse) or indirectly (through equipment or shared water sources, etc.) However, the real problem is flies. Researchers have isolated Vesicular Stomatitis Virus from sand flies, black flies, biting midges, horse flies, deer flies, house flies, mosquitoes, and eye gnats!

The incidence of this disease is extremely variable. As little as 5% or as many as 90% of exposed animals may become infected. The incubation period is 2-8 days.


There is no treatment for this disease. Affected horses usually recover within 2-3 weeks. They may need supportive care if they are lame, unwilling to eat, or dehydrated. Your vet may recommend cleaning the lesions with a mild antiseptic solution. Additionally, your vet may recommend anti-inflammatory medications to improve your horse’s level of comfort. If secondary bacterial infection occurs, affected horses may need antibiotic therapy.

Control and Prevention

Because flies are such an important component of this disease, fly masks are strongly recommended during outbreaks. Consistent and effective fly control around the barn is critical, including manure removal. Owners should isolate affected animals and not share any equipment between horses. For a very informative and comprehensive list of suggestions on how to limit the spread of VS, please read this article from New Mexico State University.


Vesicular Stomatitis is a reportable disease. An article from Colorado State University states:

VSV is federally listed as a foreign animal disease, meaning it is among several animal diseases that are highly infectious, are reported to state and federal health agencies, and are monitored closely by health officials because of the potential for widespread illness and devastating economic consequences..

Vesicular Stomatitis is considered a high-impact equine diseaseThat means it possesses one or more of the following qualities:

  • High morbidity (infection rate) or mortality (death rate). As stated above, the morbidity can vary from 5-90%!
  • There is potential human infection. Humans exhibit flu-like symptoms.
  • It is a foreign animal disease or a domestic disease with unexpected virulence.
  • Owners and veterinarians have few intervention or treatment options.
  • There is a severe impact on trade or livestock sales and transport. For instance, horse shows and events are often canceled during VS outbreaks.
  • An outbreak impacts a large number of horses/owners/facilities.
  • Any disease which creates a large degree of concern or panic in the equine industry.
What does all of this mean for me?

Your biggest takeaway from this post should be that you need to be aware of where VS is occurring in the United States. If you plan to travel to one of the affected states, you will absolutely need a health certificate. Health certificates may need to be issued closer to departure than is normally required. Additionally, you might find yourself quarantined away from home if your horse is exposed. The quarantine period is 21 days.

Don’t share buckets with other people when you travel or stay overnight at a horse B & B. Apply all of the safety information you have learned about COVID-19 to reducing your horse’s exposure to VS!

If your horse does become ill with this disease, remember that it is rarely fatal. My guess is that horses that do succumb to this disease probably had other issues before becoming ill with VS. (That sounds like some of the COVID reported deaths, doesn’t it? How does one determine if COVID-19 caused a person’s death when they were already compromised by one or more serious health issues?) While this virus will make your horse very uncomfortable, he will survive.

strongly encourage you to read the article from New Mexico State University that I linked above. It is a very good article.

Update on Past Blogs

In The Week From Hell, I wrote about rain in the kitchen of the lakehouse. I said the sale was likely to go through. I was wrong. The buyers wanted a ridiculous amount of money from the insurance company. They backed out of the deal. So we are back to Square One.

Sadie’s head is healing nicely. We just spent another bunch of money to construct TWO dry lots, so Kadeen can no longer beat up on his lady love.

No such luck on getting a filling instead of a crown. I needed a crown. Cha-CHING!

As of June 23rd, the word was that the horse I wrote about in NetPosse Alert has not been found. So very sad…

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