The Colorado Department of Agriculture has confirmed new detections of Vesicular Stomatitis (VSV) in La Plata and Archuleta counties in 2026, bringing the disease to two additional Colorado counties.

Both newly affected premises are private residences where equids are the only livestock present. On one premises, one of three horses is presenting with lesions on the lips and tongue. On the second premises, two horses living with several mules are also presenting with lip and tongue lesions. Both infections are believed to have been locally acquired.

Cases were examined by accredited veterinarians who collected samples, reported to the State Veterinarian's Office, and submitted samples for testing to Colorado State University. Both premises have been placed under state quarantine.

The previously quarantined premises in Montezuma and Montrose counties have been released from quarantine.

Colorado remains one of three states with confirmed VSV cases since October of 2025, along with Arizona and New Mexico. Arizona's last quarantine was released on April 20, 2026. New Mexico still has two affected counties with quarantined premises.

Veterinarians should report any cases with clinical signs suggestive of VSV to the State Veterinarian's Office at (303) 869-9130. Reporting quickly benefits clients and reduces negative implications for other owners.

Colorado veterinarians and livestock owners moving animals interstate should contact the destination state before movement to confirm all import requirements are met. States may impose restrictions on horses and livestock from VSV-affected states, including timed certificates of veterinary inspection or additional requirements. Some states may disable the eeCVI function in Global Vet Link and may not allow equines to move on a trip permit.

If a destination state requires certification that livestock do not originate within a specified distance of a VSV-quarantined premises, contact the State Veterinarian's Office at (303) 869-9130.

Canada restricts movement from VSV-affected states. Equine and livestock may not move directly from a VSV-affected state to Canada. Animals must remain in an unaffected state for a minimum of 21 days before becoming eligible for export to Canada. Canada does not lift these restrictions for at least 30 days following release of the last VSV quarantine in an affected state.

Updated guidance documents and case information are available on the Colorado Department of Agriculture's VSV webpage. The full situation report can be found at the USDA-APHIS VSV website.