Among such names are postviral fatigue syndrome, Icelandic disease, neurasthenia, chronic mononucleosis and even "yuppie flu."

(Today, chronic fatigue syndrome also is known as myalgic encephalomyelitis, postviral fatigue syndrome, and chronic fatigue and immune dysfunction syndrome.)

Behan PO, Behan WM, Horrobin D. Effect of high doses of essential fatty acids on the postviral fatigue syndrome.

The proposed U.S. classification ICD-10-CM (2010 Update replaces July 2009 version) separates CFS and Postviral fatigue syndrome into mutually exclusive categories.

The clinical symptoms have been described in the medical literature for at least half a century under such names as epidemic neuromyasthenia, myalgic encephalitis, Iceland disease, Royal Free disease and postviral fatigue syndrome.

As our defence systems against pathogens improve, so does the adaptability of the pathogens to each new environment we provide, a point which is amply illustrated by the emergence of apparently 'new' diseases such as Legionnaire's disease, myalgic encephalomyelitis,(postviral fatigue syndrome) and acquired immune deficiency syndrome (AIDS).