Studies on enterovirus in patients with chronic fatigue syndrome.
Gow, J W, Behan, W M, Simpson, K et al. · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 1994 · DOI
Quick Summary
Researchers tested muscle tissue from 121 ME/CFS patients and 101 people with other muscle disorders to look for enterovirus (a common virus). They found the virus in about 26% of ME/CFS patients and 20% of the comparison group—a difference too small to be meaningful. This contradicts their earlier, smaller study which had found much higher rates in ME/CFS patients, suggesting enterovirus may not be a major ongoing cause of the illness.
Why It Matters
For decades, researchers have investigated whether viral infections trigger or maintain ME/CFS. This study addressed whether enterovirus—a virus known to cause post-viral illness—is persistently present in muscle tissue of ME/CFS patients. Understanding potential viral contributions remains important for developing targeted treatments and understanding disease mechanisms.
Observed Findings
26.4% (32/121) of ME/CFS muscle biopsies tested positive for enterovirus by PCR
19.8% (20/101) of other neuromuscular disorder muscle biopsies tested positive for enterovirus
The difference between groups was not statistically significant
Results contrasted with authors' previous study showing 53% positivity in CFS vs 15% in controls
Large sample size (121 CFS patients) compared to previous smaller study (60 CFS patients)
Inferred Conclusions
Persistent enterovirus infection in muscle is unlikely to play a primary pathogenic role in CFS
An initiating role for enterovirus in disease onset cannot be excluded based on these findings
The discordance between this study and the authors' earlier work raises questions about methodology and reproducibility
Enterovirus may not be a common feature of established ME/CFS despite potential involvement in disease initiation
Remaining Questions
Why did this larger study show such different results than the authors' previous smaller study, and which findings are more reliable?
Could enterovirus involvement be limited to specific ME/CFS subgroups rather than the general CFS population?
What This Study Does Not Prove
This study does not prove that enterovirus plays no role in ME/CFS—it only suggests persistent infection in muscle may not be widespread. The negative findings don't exclude enterovirus involvement in the central nervous system, initial disease triggering, or other tissue compartments. The contradiction with their earlier positive findings raises questions about reproducibility and study design rather than definitively settling the question.
Tags
Symptom:Fatigue
Biomarker:Blood Biomarker
Phenotype:Infection-Triggered
Method Flag:PEM Not DefinedWeak Case DefinitionSmall Sample