Colo. livestock owners warned about virus

New Mexico has reported a second case of vesicular stomatitis (VS) that was confirmed on May 31 near the town of Peralta, just south of Albuquerque. This second case represents a northern movement of the virus that has been typical in past years. The primary spread of VS is thought to occur through insect vectors that migrate along river valleys. Colorado livestock owners are warned to take added precautions due to the proximity of the virus.

VS is a Foreign Animal Disease that occurs sporadically in certain areas of the western United States. Index cases are typically seen in Texas, New Mexico or Arizona. The last confirmed case of VS in Colorado was in 2006. Veterinarians and livestock owners who suspect an animal may have vesicular stomatitis or any other vesicular disease should immediately contact State or Federal animal health authorities. Livestock with symptoms of VS are isolated until they are cleared through the U.S. Department of Agricultureís diagnostic laboratory testing. There are no USDA approved vaccines for VS.

While rare, human cases of VS can occur, usually among those who handle infected animals. VS in humans can cause flu-like symptoms and only rarely includes lesions or blisters.

Vesicular Stomatitis (VS) Signs and Transmission

VS susceptible species include horses, cattle, sheep, pigs, deer and other species of animals. The clinical signs of the disease include vesicles, erosions and sloughing of the skin on the muzzle, tongue, teats and above the hooves of susceptible livestock. Vesicles are usually only seen early in the course of the disease.

As the disease progresses, the ruptured vesicles erode to produce areas where the epithelium sloughs. Animals with oral lesions may refuse to eat and/or drink due to discomfort which results in weight loss. Coronary band lesions can result in lameness in one or more feet. In severe situations, the hoof may slough or hoof growth may be permanently impacted.

The transmission of VS virus is not fully understood. Most cases are likely spread by insect vectors particularly along river valleys. Biting flies have been shown, both in natural and experimental infections, to be capable of transmitting VS. Sand flies (Lutzomyia spp.) and black flies (Simulium spp.) have been identified as important species in the transmission of VS.

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.

Colorado livestock owners should 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 veterinariansí offices is available at: www.colorado.gov/ag/animals.

Colorado fairs, livestock exhibitions, and rodeos may institute new entry requirements based on the extent and severity of the current VS outbreak. Be sure to stay informed of any new changes to event requirements.

For additional information, contact the Colorado State Veterinarianís office at 303-239-4161 or visit www.aphis.usda.gov/publications/animal_health/content/printable_version/fs_vesicular_stomatitis_07.pdf.