Ague is an old-fashioned term for a FEVER or illness, usually accompanied by CHILLS and fatigue. It is often used to describe MALARIA, which is caused by a parasite and is characterized by recurring fevers, CHILLS, and sweating. Other illnesses associated with ague include the FLU, which is caused by a virus and is characterized by FEVER, body aches, and fatigue; and FEBRILE, which is a feverish state caused by an infection or other medical condition. Ailed is another term for being sick or ill.