The foot and mouth disease (FMD) virus is one of the most infectious animal disease viruses known. It causes blisters on the mouth, teats, and soft tissues of the feet of cloven-hoofed (split-hoofed) animals such as cattle, sheep, pigs, and goats as well as some species of wildlife. Infected animals have difficulty eating and walking and lose weight rapidly. They suffer production loss from which they rarely recover.

The FMD virus may be brought into a country when meat products such as sausage, jerky, or ham made from animals with the virus are fed to pigs or other animals. The virus spreads very easily by animal contact, such as at livestock markets or county fairs and through trucks, utensils, and clothing that have been in contact with infected animals. The virus can travel long distances from an infected farm on wind currents and infect animals many miles away.

The disease is feared because it spreads so rapidly, making it very difficult and costly to control. Any country that suffers from foot and mouth disease immediately loses its export markets for animals, meat and meat products, and dairy products.