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Several of the more common alternative names used to describe what most believe to be the same condition or subtypes include myalgic encephalomyelitis ( ME ) , chronic fatigue immune dysfunction syndrome ( CFIDS ) , and post-viral fatigue syndrome ( PVFS ) .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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