If you take care of children, you need the facts about hand, foot, and mouth disease. Hi, I'm Dr. Eileen Schneider, a medical epidemiologist at the CDC. Hand, foot, and mouth disease is a contagious illness caused by viruses. It mainly affects children younger than five, but older children and adults can get it, too. Hand, foot, and mouth disease is sometimes confused with foot and mouth disease, but the two have nothing to do with each other.