Foot-and-mouth disease, highly contagious disease almost exclusive to cattle, sheep, swine, goats, and other cloven-hoofed animals. It is caused by a virus that was identified in 1897. Among its symptoms are fever, loss of appetite and weight, and blisters on the mucous membranes, especially those of the mouth, feet, and udder. Discharge from the blisters is heavily infected with the virus, as are saliva, milk, urine, and other secretions. Thus the disease is readily spread by contact; by contaminated food, water, soil, or other materials; or through the air. Humans, who seldom contract the disease, may be carriers, as may rats, dogs, birds, wild animals, and frozen meats.
They actually use Labradors at ports to sniff out meat infected with foot and mouth coming in from abroad (don't think they would do that if the dog could catch it!).