Vesicular Stomatitis (VS) is a contagious disease caused by a virus. It is seen mainly west of the Mississippi, especially in the Rocky Mountains and Southwest regions. VS is prevalent in Mexico, Central and South America. In horses, VS appears as blisters in the mouth and nose which may lead to crust formation on the muzzle and excessive drooling. Most horses will become depressed and lose appetite. Ulcers may also form on the genitals, udder, and coronary bands of the feet. The symptoms last about 10 days. VS rarely causes death in horses, and most recover fully without any long-term complications.
Transmission of VS is by exposure to respiratory and oral secretions (or any other bodily fluid), sexual contact, and possibly by biting insects (unproven in the field). Fomites are also possible routes of infection. Fomites are inanimate objects like clothing, tack, equipment, grooming supplies, troughs, and feed buckets that may carry the virus from one horse to another. No approved vaccine for VS is available, so proper sanitation, quarantine procedures, and insect control measures are all required to prevent an epidemic.
Vesicular Stomatitis is a reportable disease, meaning a suspected case must be brought to the attention of a veterinarian immediately. The veterinarian must in turn notify the state health department within 24 hours. This is because the clinical symptoms associated with VS are very similar to those seen in Foot and Mouth Disease (FMD) which affects swine and cattle. FMD has been eradicated from many parts of the world, and it is strictly monitored for resurgence into these areas because of its economic impacts on the meat industry. Even though VS is not a huge threat to horses, it is a huge threat to the cattle and swine industry.
USDA inspectors will verify VS in the laboratory and assist with proper quarantine measures if the disease is suspected. Quarantine remains in place for 30 days beyond the resolution of any clinical symptoms seen in affected animals.