Vesicular stomatitis is a viral disease that can affect horses, swine, cattle, and other ruminants. It causes affected livestock to develop blisters in the mouth and on the dental pad, hooves, and teats. These blisters swell and break, leaving raw tissue that causes affected animals to become lame and to refuse food and water. The disease also is of concern because its symptoms are similar to those of foot-and-mouth disease, a devastating foreign disease of clovenhoofed animals that was eradicated from the United States in 1929. The only way to diagnose and