Two horses in Maricopa County have been confirmed with Vesicular Stomatitis Virus (VSV) in the East Valley. VSV is a contagious virus which causes blister-like sores on the mouths, noses and sometimes feet of infected animals. The Department of Agriculture is testing animals from a total of eight locations in Maricopa County.

"Vesicular Stomatitis Virus mainly affects equine and to a lesser extent cattle and swine," said State Veterinarian Dr. Perry Durham. "It can be painful for animals and costly to deal with."

The blisters are most likely to affect the mouth, the tongue and around the nose/muzzle. Pain from the blisters can make it hard for the animal to eat and drink. If cattle are infected, often the hooves and teats are involved leading to severe economic impact in dairy cattle.

In cattle, this virus is basically visually indistinguishable from Foot and Mouth Disease (FMD), a highly contagious and devastating disease. Tests on the affected steer for Foot and Mouth Disease came back negative.

The affected horses seem to be sicker with this outbreak than the small outbreak Arizona saw earlier this year. 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 clinical signs of Vesicular Stomatitis are isolated until they are healed and determined to be of no further threat for disease spread. There are no USDA approved vaccines for Vesicular Stomatitis.

Though very unusual, people can be infected with the virus. In these situations, it is usually among those who handle infected animals (for example while inspecting a horse's mouth and the horse coughs in the person's face thereby delivering a large dose of virus onto the person's eyes and lips). Vesicular Stomatitis Virus can cause flu-like symptoms and only rarely includes lesions or blisters in people.

More information about Vesicular Stomatitis is available online.