Vesicular Stomatitis in Delta County, Colorado

Colorado has become the fifth state in the country to have a confirmed case of vesicular stomatitis virus (VSV) this year. A six-year-old horse in Delta County tested positive for the disease, and the premise has been placed under quarantine.

"VSV is not a human health issue, but it can have severe economic impact on livestock owners, especially in the dairy industry," said Wayne Cunningham, DVM, MS, state veterinarian at the Colorado Department of Agriculture. "The disease usually doesn't result in an animal's death, but the main reason we watch it closely is due to fact that the symptoms closely resemble foot-and-mouth disease, which is much more economically devastating."

In 2004, 148 horses, 119 cattle, four sheep and goats, and two alpacas were infected with the disease, involving a total of 107 premises across the Colorado.

Vesicular stomatitis is a viral disease that is usually not fatal but causes painful lesions around an infected animal's mouth, nostrils, teats, and hooves, with symptoms similar to foot and mouth disease (FMD). Only laboratory tests can differentiate between VSV and FMD. All disease samples from Colorado were sent to the National Veterinary Services Laboratory in Ames, Iowa, for testing.

Vesicular stomatitis virus primarily affects cattle, horses, and swine. The infected animals' blisters enlarge and break, leaving raw tissue that is so painful the animals generally refuse to eat or drink and they show signs of lameness. Severe weight loss usually follows.

Since the disease is believed to be spread by insects, preventive measures include keeping susceptible animals in dry corrals and stables, using insecticides and insect repellents daily, providing good nutrition, and practicing good management.

Prior to 2004, the last case of VSV in Colorado was diagnosed in 1998. Although vulnerable, humans are rarely infected with the disease and usually display flu-like symptoms if they contract VSV. In addition to those species mentioned, other susceptible animals include llamas, and wild animals such as deer, bobcats, and raccoons. For more information on VSV, visit


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