Vesicular Stomatitis Confirmed in Colorado

A Las Animas County, Colo., premises is under quarantine after a horse tested positive for vesicular stomatitis (VS); the horse had not recently traveled and is believed to have been infected by insects.

"While this is the first case diagnosed in Colorado in 2012, there have been several cases identified in the Rio Grande River valley of New Mexico," said Colorado State Veterinarian Keith Roehr, DVM. "This Colorado case represents a northern movement of the virus that has been typical in past years."

In response, the Colorado Department of Agriculture's (CDA) State Veterinarian's Office has issued a travel requirement for horses, mules, cattle, bison, sheep, goats, swine, and camelids entering the state from states with confirmed cases of VS. This requirement states that health certificates should include the following statement from the issuing veterinarian: "I have examined the animal(s) represented on this Certificate of Veterinary Inspection and have found no signs of vesicular stomatitis and they have not originated from a premises under quarantine for vesicular stomatitis."

"The purpose of this requirement is to ensure that veterinarians issuing health certificates are aware of the spread of vesicular stomatitis and are vigilant in looking for signs of the virus," Roehr said. "VS can be painful for the animals and costly to their owners. While this virus does not typically cause death, the animal can suffer from painful sores so it is important to monitor herds for symptoms."

A viral, foreign animal disease that occurs sporadically in the United States, VS usually appears in southwestern states. The disease, thought to be transmitted by sand flies and black flies, can affect horses, cattle, and swine and occasionally sheep, goats, and deer. It causes blisters to form in the animal's mouth, on teats, or along the hooves, resulting in excessive salivation, lameness, or oozing sores.

VS can incubate for two to eight days before clinical signs appear. It is rarely fatal and usually lasts about two weeks before clearing up. The last confirmed case of VS in Colorado was diagnosed in 2006.

The CDA has issued the following tips for livestock owners:

  • Strict fly control is an important factor to inhibit the transmission of the disease.
  • Avoid transferring feeding equipment, cleaning tools, or health care equipment from other herds.
  • Contact the state of destination when moving livestock interstate to ensure that all entry requirements are met. A list of contact information for all state veterinarians' offices is available at:
  • Colorado fairs, livestock exhibitions, and rodeos can institute new entry requirements based on the extent and severity of the current VS outbreak. Be sure to stay informed of any new changes concerning event requirements.

For additional information, contact the Colorado State Veterinarian's office at 303-239-4161 or visit To view the current location of cases, visit

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