The spread of vesicular stomatitis continues across the Southwest with a new case reported in a horse in Las Animas County Colorado, resulting in new Colorado travel rules to be issued for New Mexico horses, mules, cattle, bison, sheep, goats, swine and camelids entering the state.

As of July 25, more than 20 New Mexico premises have had horses test positive for VS. Counties with confirmed cases include Rio Arriba, San Miguel, Sandoval, Socorro, Valencia and Lincoln. In addition, other counties in the state are under observation.

The latest case in Colorado has animal health officials concerned as the horse had not recently traveled to or from New Mexico and is believed to have been infected by insect bite.

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