Chronic fatigue syndrome (CFS) is an emerging illness characterized by debi=
litating
fatigue (experienced as exhaustion and extremely poor stamina), neurologica=
l
problems, and a variety of flu-like symptoms. The illness is also known as =
chronic
fatigue immune dysfunction syndrome (CFIDS), and outside of the USA is usua=
lly
known as myalgic encephalomyelitis (ME). In the past the syndrome has been =
known
as chronic Epstein-Barr virus (CEBV).

The core symptoms include excessive fatigue, general pain, mental fogginess=
, and often
gastro-intestinal problems. Many other symptoms will also be present, howev=
er they
will typically be different among different patients. These include: fatigu=
e following
stressful activities; headaches; sore throat; sleep disorder; abnormal temp=
erature; and
others.

The degree of severity can differ widely among patients, and will also vary=
 over time
for the same patient. Severity can vary between getting unusually fatigued =
following
stressful events, to being totally bedridden and completely disabled. The s=
ymptoms will
tend to wax and wane over time. This variation, in addition to the fact tha=
t the cause of
the disease is not yet known, makes this illness difficult to diagnose.