Mucosal Viruses in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Missing Piece of the Puzzle?
Perera, Krishani Dinali, Cameron, Paige, Sarwar, Tayyibah et al. · International journal of molecular sciences · 2025 · DOI
Quick Summary
Many people with ME/CFS report that their illness started after a viral infection, but scientists haven't found clear evidence of viruses in their blood. This review suggests researchers have been looking in the wrong places—focusing on blood instead of mucosal tissues (like the throat and gut lining) where viruses naturally enter the body and may hide. The authors propose that viruses could be persisting in these mucosal sites and occasionally reactivating, potentially triggering the ongoing inflammation and symptoms that characterize ME/CFS.
Why It Matters
This perspective highlights why many viral studies in ME/CFS have produced conflicting or negative results—they may have been sampling the wrong biological sites. Understanding whether viruses persist in mucosal tissues could eventually lead to better diagnostic tests, targeted treatments, and explanation of why some patients experience post-viral illness onset.
Observed Findings
Most ME/CFS studies to date have focused on detecting viruses in blood and circulating immune cells rather than mucosal tissues
Mucosal tissues serve as primary entry points for most pathogens and commonly act as viral reservoirs
Emerging evidence from saliva and other mucosal samples in ME/CFS patients is consistent with latent viral persistence and periodic reactivation
Most ME/CFS patients report post-viral illness onset, yet findings on specific viral triggers remain conflicting
Latent viruses persisting in mucosal tissues could potentially contribute to immune dysregulation and chronic inflammation characteristic of ME/CFS
Inferred Conclusions
Mucosal tissues represent a critical and previously understudied site for identifying persistent viral infections in ME/CFS
Viral persistence and reactivation in mucosal tissues may explain the post-viral symptom onset reported by many ME/CFS patients and the chronic immune dysregulation observed in the condition
Future ME/CFS viral research should prioritize mucosal sampling sites alongside or instead of blood-based investigations
Both single persistent viruses and multiple mucosal viral reactivations may contribute to ME/CFS pathophysiology
Remaining Questions
What This Study Does Not Prove
This editorial does not provide original experimental evidence that mucosal viruses cause ME/CFS or definitively prove viruses are present in mucosal tissues of ME/CFS patients. It is a hypothesis-generating review proposing future research directions, not a definitive demonstration of causation. The connection between mucosal viral persistence and the specific symptoms of ME/CFS remains to be rigorously established.
Which specific viruses, if any, persist in mucosal tissues of ME/CFS patients and how frequently do they reactivate?
Does mucosal viral presence or reactivation directly cause the immune dysregulation and symptom severity seen in ME/CFS, or is it a secondary consequence?
How should mucosal viral persistence be detected reliably and systematically across different patient populations to establish prevalence and specificity?
What mechanisms allow mucosal viral persistence to trigger systemic immune activation and chronic fatigue if viremia is not consistently detected?