Katzourakis, Aris, Hué, Stéphane, Kellam, Paul et al. · Journal of virology · 2011 · DOI
This study examined whether a virus called XMRV, found in some ME/CFS patients' samples over 15 years apart, could have naturally evolved within patients' bodies. Using genetic analysis, the researchers found that the virus sequences were actually different types of mouse viruses, not the same virus changing over time. This suggests the virus detections were likely due to laboratory contamination rather than evidence of an actual persistent infection.
This study addresses a critical concern in ME/CFS research regarding the validity of XMRV findings, which generated significant attention and debate in the field. By providing rigorous evidence against true viral persistence and evolution, it clarifies that previous XMRV detections in CFS samples were contamination artifacts, helping redirect research efforts toward more reliable etiological investigations. Understanding what did not cause ME/CFS is as important as identifying what did.
This study does not prove that no virus is involved in ME/CFS, only that XMRV specifically is not a persistent, evolving infection in these patients. The findings refute the longitudinal XMRV persistence hypothesis but do not address whether other viruses might contribute to ME/CFS pathogenesis. The study also does not explain why initial XMRV amplifications occurred or what role viral contamination in research samples played in prior conflicting results.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Katzourakis, Aris, Hué, Stéphane, Kellam, Paul, & Towers, Greg J (2011). Phylogenetic analysis of murine leukemia virus sequences from longitudinally sampled chronic fatigue syndrome patients suggests PCR contamination rather than viral evolution.. Journal of virology. https://doi.org/10.1128/JVI.00827-11
BibTeX
@article{mecfsatlas-katzourakis-2011-phylogenetic-analysis,
author = {Katzourakis, Aris and Hué, Stéphane and Kellam, Paul and Towers, Greg J},
title = {Phylogenetic analysis of murine leukemia virus sequences from longitudinally sampled chronic fatigue syndrome patients suggests PCR contamination rather than viral evolution.},
journal = {Journal of virology},
year = {2011},
doi = {10.1128/JVI.00827-11},
note = {PubMed: 21849443},
url = {https://www.mecfsatlas.com/evidence/katzourakis-2011-phylogenetic-analysis},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/katzourakis-2011-phylogenetic-analysis
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