Many studies on enterovirus infections in ME/CFS patients looked at muscle tissue biopsies, and found enterovirus present in the muscle tissues. The muscles are not the only tissues or organs that enterovirus likes to infect, but it makes me wonder whether the muscle pain might be caused by this enterovirus infection of the muscles.
All the following ME/CFS studies found enterovirus infections in the muscle tissues:
Enteroviral RNA sequences detected by polymerase chain reaction in muscle of patients with postviral fatigue syndrome
Gow JW, Behan WM, Clements GB, Woodall C, Riding M, Behan PO.
BMJ. 1991 Mar 23;302(6778):692-6.
➤ This study found 20% of ME/CFS patients had high titers to coxsackievirus B, compared to 14% of controls. Furthermore,
53% of these ME/CFS patients had enteroviral RNA sequences in their muscles, compared to 15% for health controls.
Amplification and identification of enteroviral sequences in the postviral fatigue syndrome
Gow JW1, Behan WM. Br Med Bull.
1991 Oct;47(4):872-85.
➤ This study found that
ME/CFS patients were 6.7 times more likely to have enteroviral RNA in their muscle tissue, compared to healthy controls.
Persistent virus infection of muscle in postviral fatigue syndrome
Cunningham L, Bowles NE, Archard LC.
Br Med Bull. 1991 Oct;47(4):852-71.
➤ This study found
enteroviral RNA in 24% of ME/CFS patients' muscle biopsy samples, and Epstein-Barr virus DNA in a further 9% of these biopsy samples.
Persistence of enterovirus RNA in muscle biopsy samples suggests that some cases of chronic fatigue syndrome result from a previous, inflammatory viral myopathy
Bowles NE, Bayston TA, Zhang HY, Doyle D, Lane RJ, Cunningham L, Archard LC.
J Med. 1993;24(2-3):145-60.
➤ This study found
enteroviral RNA in 26% of ME/CFS patient's muscle biopsy samples, compared to 1% in healthy controls.
Studies on enterovirus in patients with chronic fatigue syndrome
Gow JW, Behan WM, Simpson K, McGarry F, Keir S, Behan PO.
Clin Infect Dis. 1994 Jan;18 Suppl 1:S126-9.
➤ This study found
enteroviral RNA in 26.4% of ME/CFS patient's muscle biopsy samples, and found enteroviral RNA in 19.8% the muscle biopsies of patients other neuromuscular disorders. From these results the authors concluded that "
it is unlikely that persistent enterovirus infection plays a pathogenetic role in CFS." However, this conclusion may not be a logical, since enterovirus is associated with a wide range of diseases, and thus might also be playing a role in these other neuromuscular disorders.
Enterovirus in the chronic fatigue syndrome (full text
here)
McGarry F, Gow J, Behan PO.
Ann Intern Med. 1994 Jun 1;120(11):972-3.
➤ This study details an autopsy of a deceased ME/CFS patient. Enteroviral RNA was found in the heart,
muscles, hypothalamus and brainstem of this patient, and this RNA showed an 83% similarity to coxsackievirus B3. Control tissue samples taken from four patients who died of cerebrovascular diseases, and another four who had depression and committed suicide, showed no evidence of enteroviral RNA.
Enterovirus related metabolic myopathy: a postviral fatigue syndrome
Lane RJ, Soteriou BA, Zhang H, Archard LC.
J Neurol Neurosurg Psychiatry. 2003 Oct;74(10):1382-6.
➤ This study found
enteroviral sequences by RT-NPCR in 20.8% of ME/CFS patient's muscle biopsy samples, while all the 29 control samples were negative for such sequences.