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August 16, 2005     E-mail this page to a friend!

 (Helena, Mont.) – The first case of vesicular stomatitis (VS) in Montana since 1982 has been confirmed in a horse in Yellowstone County, according Dr. Tom Linfield, Montana State Veterinarian.

Wyoming also reported its first case today, which follows previously reported cases in Colorado, Utah, New Mexico, and Arizona. Although Texas had confirmed cases of VS this spring, the state no longer has any premises under quarantine.

“An epidemiological investigation is ongoing at this time to try and determine the potential source of infection,” Dr. Linfield said. “The attending veterinarian immediately recognized that the clinical signs of severe tongue lesions were suggestive of VS and blood samples were taken. Test results confirmed the diagnosis of VS.”

The premises of the animal is currently under quarantine.

This diagnosis will affect Montana horses and susceptible animals traveling out of state, and we would anticipate the export of susceptible animals to Canada, as well as other countries, may be prohibited, “ Dr. Linfield said. “Animal owners and veterinarians should be aware that interstate restrictions will apply, and veterinarians should check the destination state or country to comply with specific requirements.”

VS is a viral disease that primarily affects horses, cattle, and swine, but may affect goats, sheep, llamas and alpacas.

It is not fully known how the vesicular stomatitis virus (VSV) is spread. It is believed to be spread through insect vectors, such as the sand fly and the black fly, movement of infected animals, and contaminated objects such as water troughs and feed bins. Once introduced into a herd, the disease apparently moves from animal to animal by contact or exposure to saliva or fluid from ruptured lesions.

Montana import requirements will not be affected by this case of VS. “We will still require animals traveling from VS-affected states to have a Certificate of Veterinary Inspection issued within 72 hours of import into Montana,” Dr. Linfield said. In addition, shipments originating within 10 miles of an infected premises will require veterinary inspection within 24 hours of import.

The signs of VS are similar to those of foot-and-mouth disease (FMD); however, horses are not susceptible to FMD. In affected livestock, VSV causes blister-like lesions to form in one or several of the following locations: mouth, dental pad, tongue, lips, nostrils, on the coronary bands, or on the teats. These blisters swell and break, leaving raw tissue that is so painful that infected animals generally refuse to eat and drink and may show signs of lameness. Severe weight loss usually follows. VS rarely causes death, but an animal can suffer several weeks while the lesions heal.

Owners can help protect their animals from this disease by avoiding traveling to or congregating in areas known to be affected with VS. Good sanitation practices should be used, as well as isolating new additions to the herd or animals returning to the herd or premises.

Livestock owners and private veterinary practitioners should report suspected cases of VS to the Montana Department of Livestock at 444-2043 or USDA Animal and Plant Health Inspection Service regional office at 449-2220.

The Department of Livestock web site at has additional information on VS, including a link to USDA at where situation reports, maps and movement restrictions and requirements are posted.