The most common cause of hand-foot-and-mouth disease is infection with the coxsackievirus A16. The coxsackievirus belongs to a group of viruses called nonpolio enteroviruses. Other types of enteroviruses sometimes cause hand-foot-and-mouth disease.
Oral ingestion is the main source of coxsackievirus infection and hand-foot-and-mouth disease. The illness spreads by person-to-person contact with an infected person's: