What is vesicular stomatitis?
Vesicular stomatitis is a zoonotic viral disease that primarily affects equines, cattle and swine. The virus can also infect sheep and goats as well as wildlife and other mammals. Humans can, but rarely do, become infected by handling infected animals or contaminated equipment.
The disease is considered endemic to warmer regions of the Western Hemisphere, with outbreaks occasionally occurring in temperate regions. In the U.S., VS is most likely to occur during warm months in the southwest, particularly along river ways and in valleys.
How vesicular stomatitis spreads is not fully understood. It is believed to be spread through insect vectors, the movement of infected animals, and using contaminated objects. Once introduced into a herd, the disease can also be spread from animal to animal by contact or exposure to saliva or fluid from ruptured lesions.
Clinical Signs & Symptoms
While infected animals generally clear the virus within two weeks, VS is extremely painful and can cause weight and production losses. In affected livestock, VS causes blister-like lesions in the mouth and on the tongue, lips, nostrils, coronary bands above the hooves, and teats. These blisters swell and break, leaving raw tissue that is so painful infected animals generally refuse to eat and drink. Severe weight loss can follow.
The incubation period for VS in livestock ranges from two to eight days, and it takes about that long for vesicles to appear. In addition to the painful blisters and lesions described above, VS can also cause a temporary spike in body temperature. Slobbering may precede the onset of vesicles.
VS is particularly significant because it is clinically indistinguishable from foot-and-mouth disease (FMD), a serious foreign animal disease (FAD) eradicated from the U.S. in 1929, as well as swine vesicular disease and vesicular exanthemia of swine. Because of similarities to these FADs, it is essential to quickly confirm a diagnosis with laboratory testing. If you suspect VS in your animals, contact your veterinarian immediately.
Of the vesicular diseases, VS is the only one that affects horses, and the presence of lesions is suggestive of VS.
Any vesicular lesions on livestock should be immediately reported to MDOL and/or USDA-APHIS. Disease investigations of FADs can only be performed by trained clinicians.
There is no specific treatment or vaccination for VS. Treatment strategies include mild antiseptic mouthwashes and good sanitation to prevent secondary bacterial infections.
Owners can protect their animals by avoiding vicinities where VS has occurred. Good sanitation and quarantine practices on affected farms usually contain the virus until it dies out. When a definite diagnosis is made, the following procedures are recommended:
- Separate animals with lesions from healthy animals, preferably by stabling.
- Do not move animals from premises affected by vesicular stomatitis, unless they are going directly to slaughter, for at least 30 days after the last lesion has healed.
- Implement on-farm insect control programs that include elimination or reduction of insect breeding areas and the use of insecticide sprays or insecticide-treated ear tags on animals.
- Use protective measures when handling affected animals to avoid human exposure.
- Frequently disinfect potentially contaminated objects, such as milking machines. Effective disinfectants include 2% sodium carbonate, 4% sodium hydroxide, 2% iodophore disinfectants, chlorine dioxide disinfectants, ether and other organic solvents, and 1% formalin.
Vesicular Stomatitis is a reportable disease. Any suspected or confirmed cases should be immediately reported to the Montana State Veterinarian at 406/444-2043 or USDA-APHIS Veterinary Services at 406/449-2220.