CHRONIC FATIGUE SYNDROME

Chronic fatigue syndrome (CFS) has emerged as a public health concern over the past decade. A working case definition was created in 1988 an d revised in 1994, and this has been used to establish prevalence esti mates using physician-based surveillance and an a random digit dial te lephone survey. Although CFS has some characteristics of an infectious disease, so far no infectious agent has been associated with the illn ess. Studies of immune function in CFS patients failed to detect diffe rences between cases and healthy controls. However, when cases were su bgrouped according to whether they had a sudden or gradual onset, diff erences in immunologic markers were detected between cases and their m atched controls.