The Arizona Department of Agriculture (ADA) has confirmed vesicular stomatitis virus (VSV) in horses on a premises in Cochise County.

ADA has quarantined the case-positive premises.

The disease causes blister-like lesions to form in the mouth and on the dental pad, tongue, lips, nostrils, hooves, and teats. The blisters swell and break leaving raw tissue that is so painful that infected animals generally refuse to eat or drink and show signs of lameness.

Severe weight loss usually follows, and in dairy cows, a severe drop in milk production commonly occurs. Affected dairy cattle can appear normal and will continue to eat about half of the regular feed intake.

While VSV can cause economic losses to livestock producers, it is a particularly significant disease because its outward signs are similar to (although generally less severe than) those of foot-and-mouth disease, a foreign animal disease of cloven-hoofed animals that was eradicated from the United States in 1929.

The clinical signs of VSV are also similar to those of swine vesicular disease, another foreign animal disease. The only way to tell the diseases apart is through laboratory tests.

Humans can become infected with VSV when handling affected animals. ADA reports no human VSV cases.

Horses, swine, and cattle are most at risk. Other animals can also contract the disease.

Last year Texas and New Mexico had several cases of VSV. This year Arizona is the first state to detect the disease, which occurs sporadically on five to eight year cycles.

VSV is most likely to occur during the warm months in the Southwest, the ADA reports, particularly along river ways and valleys.

Arizona’s last confirmed case of VSV was in the spring of 2005.

ADA recommends the following actions:

• Separate animals with lesions from healthy animals preferably by stabling. Animals on pastures apparently are affected more frequently with this disease.

• As a precautionary measure, do not move animals from premises affected by VSV for at least 30 days after the last lesion found has healed.

• Implement on-farm insect control programs to eliminate or reduce insect breeding areas and use insecticide sprays or insecticide-treated ear tags on animals.

• Use protective measures when handling affected animals to avoid human exposure to the disease.

For more information, contact a veterinarian or the Arizona State Veterinarian’s office at (602) 542-4293.