Coxsackievirus A16 as a subtype of Hand, Foot, & Mouth Disease. Hand, Foot, & Mouth Disease (medical condition): Common contagious viral infant or child condition. Hand, Foot, & Mouth Disease: Hand, foot, and mouth disease (HFMD) is a common illness of infants and children.It is characterized by fever, sores in the mouth,... (Source: excerpt from Facts About Hand, Foot, & Mouth Disease: CDC-OC).HFMD is a different disease than foot-and-mouth disease of cattle, sheep, and swine.and, Foot, & Mouth Disease: Hand, foot, and mouth disease (HFMD) is a common illness of infants and children. It is characterized by fever, sores in the mouth,... (Source: excerpt from Facts About Hand, Foot, & Mouth Disease: CDC-OC). HFMD is a different disease than foot-and-mouth disease of cattle, sheep, and swine.