Colorado has confirmed a second case of Vesicular Stomatitis (VSV) in 2026, with a horse in Montrose County testing positive July 30, 2026, and the affected premises placed under quarantine.

CSU's Veterinary Diagnostic Laboratory reported the positive test results on samples submitted from one horse. The positive horse is the only symptomatic animal among three horses on the premises; no other susceptible species are present. An accredited veterinarian examined the horse, collected samples, reported the case to the Colorado Department of Agriculture, and submitted testing under the department's guidance.

This is the second affected county in Colorado following the index case in Montezuma County. The Montezuma County premises was released from quarantine on May 29th.

Colorado is 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 cases quickly benefits clients and reduces negative implications for other owners.

Colorado veterinarians and livestock owners moving livestock interstate should contact the destination state to confirm all import requirements are met. States may impose restrictions for horses and livestock coming from VSV-affected states, including a timed certificate 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. Always check with the destination state prior to movement.

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

The full situation report is available at the USDA-APHIS VSV website. Additional guidance documents and case information are maintained at the Colorado Department of Agriculture VSV webpage.