Colorado becomes third state to report vesicular stomatitis

The Colorado Department of Agriculture has issued a notice that Colorado has become the third state in the U.S. to have confirmed cases of vesicular stomatitis, also known as VSV.

On July 3, the National Veterinary Services Laboratory reported positive test results on samples submitted from two horses in Weld County. The two horses reside on separate locations in Weld County and have been placed under quarantine. The initial Colorado disease investigation was completed by a field veterinarian from the State Veterinarian’s Office at the Colorado Department of Agriculture.

Previous positive cases of vesicular stomatitis in 2019 have been diagnosed in Kinney and Tom Green counties in Texas and in Sandoval County, New Mexico.

Vesicular stomatitis can be painful for animals and costly to their owners,” said Colorado State Veterinarian, Dr. Keith Roehr. “The virus typically causes oral blisters and sores that can be painful causing difficulty in eating and drinking.”

The Weld County epidemiological investigation indicates that VSV-infected insects were the likely source of infection. Biosecurity measures and mitigation have been instituted on both locations to reduce the potential spread of the virus.

The animals are being monitored daily and the premises will remain under state quarantine until at least 14 days from the onset of lesions in the last affected animal on the premises. There are no USDA approved vaccines for VSV.

Vesicular stomatitis is a viral disease that primarily affects horses and cattle, and occasionally swine, sheep, goats, llamas, and alpacas. The transmission process of VSV is not completely understood, but includes insects such as black flies, sand flies, and biting midges.

The incubation period ranges from 2-8 days. Clinical signs include vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats, and coronary bands. Often excessive salivation is the first sign of disease, along with a reluctance to eat or drink. Lameness and weight loss may follow.

Humans may become infected when handling affected animals, but this is a rare event.  To avoid human exposure, individuals should use personal protective measures when handling affected animals.

Livestock owners are advised that strict fly control is an important factor to inhibit the transmission of the disease. They also should avoid transferring feeding equipment, cleaning tools or health care equipment from other herds.

Colorado veterinarians and livestock owners should contact the state of destination when moving livestock interstate to ensure that all import requirements are met. Contact information for all state veterinarian offices is listed here: link