UNASSIGNED: The etiology of @entity5815 also known as @entity5815 or ME/CFS has not been established. Controversies exist over whether it is an @entity347 or a @entity74 and even the existence of ME/CFS as a disease entity is sometimes denied. Suggested causal hypotheses have included @entity5539 , @entity166 , @entity1200 , @entity792 , @entity209 , toxins and @entity74 . Clinical, immunological and epidemiological evidence supports the hypothesis that: ME/CFS is an @entity166 ; the causal pathogen persists in @entity1 ; the pathogen can be transmitted by casual contact; host factors determine susceptibility to the illness; and there is a population of healthy carriers, who may be able to shed the pathogen. ME/CFS is endemic globally as sporadic cases and occasional cluster outbreaks (epidemics). Cluster outbreaks imply an infectious agent. An @entity683 resembling an @entity166 in outbreak @entity1 and many sporadic @entity1 . Immune responses in sporadic @entity1 resemble immune responses in other @entity166 . Contagion is shown by finding secondary cases in outbreaks, and suggested by a higher prevalence of ME/CFS in sporadic @entity1 ' genetically unrelated close contacts (spouses/partners) than the community. Abortive cases, sub-clinical cases, and carrier state individuals were found in outbreaks. The chronic phase of ME/CFS does not appear to be particularly infective. Some healthy @entity1 -contacts show immune responses similar to @entity1 ' immune responses, suggesting exposure to the same antigen (a pathogen). The chronicity of symptoms and of immune system changes and the occurrence of secondary cases suggest persistence of a causal pathogen. Risk factors which predispose to developing ME/CFS are: a close family member with ME/CFS; @entity74 ; female gender; age; rest/activity; previous exposure to stress or toxins; various @entity166 preceding the onset of ME/CFS; and occupational exposure of health care professionals. The hypothesis implies that ME/CFS @entity1 should not donate blood or tissue and usual precautions should be taken when handling @entity1 ' blood and tissue. No known pathogen has been shown to cause ME/CFS. Confirmation of the hypothesis requires identification of a causal pathogen. Research should focus on a search for unknown and known pathogens. Finding a causal pathogen could assist with diagnosis; help find a biomarker; enable the development of anti-microbial treatments; suggest preventive measures; explain pathophysiological findings; and reassure @entity1 about the validity of their symptoms.

@entity5815 , @entity5815 : An XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity5539 :: ('MESH:D011602', 'Disease') :: ['psychosomatic disorders'] @entity1200 :: ('MESH:D007154', 'Disease') :: ['immune dysfunctions'] @entity683 :: ('MESH:D007251', 'Disease') :: ['abrupt flu-like onset'] @entity792 :: ('MESH:D001327', 'Disease') :: ['autoimmunity'] @entity74 :: ('MESH:D030342', 'Disease') :: ['inherited genetic factors', 'psychological disorder'] @entity5815 :: ('MESH:D015673', 'Disease') :: ['chronic fatigue syndrome', 'myalgic encephalomyelitis'] @entity209 :: ('MESH:D008659', 'Disease') :: ['metabolic disturbances'] @entity166 :: ('MESH:D003141', 'Disease') :: ['infectious diseases', 'infectious illness occurs', 'infectious agents', 'infectious disease'] @entity347 :: ('MESH:D019965', 'Disease') :: ['organic disease']
@entity166 :: (MESH:D003141,Disease) :: ['infectious disease']
