List of enterovirus infection studies

Enteroviruses such as Coxsackie B have long been associated with myalgic encephalomyelitis, with nearly thirty positive studies finding evidence of enteroviral persistence in ME patients. The enterovirus theory of ME/CFS is the oldest and probably most researched. Early studies in the 1970s and 1980s focused on the elevated coxsackievirus B antibody titers often found in ME/CFS patients, but once molecular testing methods became available towards the end of the 1980s, studies were then able to directly detect enteroviral RNA in the muscle, stomach and brain tissues of ME/CFS patients, as well as detecting enterovirus VP1 protein in these tissues.

The majority of these enterovirus studies have been positive (finding enterovirus much more commonly in ME/CFS patients than healthy controls), and in the list below positive studies are indicated by a + symbol. However, there were also 4 negative studies (finding no difference between patients and healthy controls) and these are indicated by the − symbol. Note that two of these negative studies had small cohorts of only around 30 patients.

Early ME/CFS enterovirus research
This early period of enterovirus research from 1970 to 2003 (comprises mainly British studies).

Dr John Chia's ME/CFS enterovirus research
John Chia in California: his research papers on enterovirus in ME/CFS from 2005 to present.

Other investigations by John Chia
Dr Chia took more than 2500 blood samples from more than 510 ME/CFS patients, and in their peripheral blood lymphocyte (PBL) cells, 35% of these patients tested positive for enterovirus RNA, using a very sensitive test: the Chemicon RT-PCR EAI 3 primer test, with Qiagen 1-step RT-PCR enzyme.

Interestingly, for the more severe bedridden patients, Dr Chia found enterovirus RNA in 70% of the PBL cells. But for the less ill patients, enterovirus RNA was found in only 12%.

The sensitivity of the test was high, around 80 to 800 RNA copies per ml of blood, yet typically the same patient would not always test positive using this test (they would be positive on some occasions and negative on others), so Chia says it is clear that the enteroviral RNA present in the blood in ME/CFS is at very low levels. Dr Chia says any PCR tests which have insufficient sensitivity (above 1000 copies of RNA per ml of blood) will almost always give negative results in ME/CFS patients.