These patients all suffered from an infection similar to a herpes-type virus that produces mononucleosis.

What set the Incline Village patients apart from others, however, was the fact that they did not appear to get better after they recovered from the initial infection. In fact, they continued to have bone-weary fatigue, sleep disturbances, mood swings, lymphadenopathy, and intolerance to exercise. This series of symptoms was not characteristic of normal recovery from flu. As a consequence, Dr. Cheney coined the term “chronic fatigue syndrome” to describe this condition. An ensuing report described similarities between this condition and myalgia encephalitis, or ME, as it was called in England.*
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Research ensued, along with heightened interest that was further fueled by a number of veterans returning from the Gulf War Campaign with a similar constellation of fatigue, and CFS- and FM-related symptoms called “Desert Storm Syndrome.”
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CFS symptoms can fluctuate, vary in intensity and appear either suddenly or gradually. Many patients complain of “brain fog.” This is described as slow thinking, difficulty focusing, and forgetfulness."