(CBS/AP) Is chronic fatigue syndrome caused by a virus? It no longer appears to be the case.
The journal Science has decided to put that link to rest by officially retracting the original research paper that first suggested chronic fatigue syndrome was caused by the virus "XMRV" typically found in mice.
The original paper from scientists at the Whittemore Peterson Institute in Reno, Nev. - first published in 2009 - reported that XMRV was found in blood samples of patients with chronic fatigue syndrome. But since then other studies have not been able to replicate the findings.
The journalthat the paper's validity was "seriously in question" after two studies suggested the viral link may have been due to contaminated lab samples. Then in September, a new study found no link between XMRV and chronic fatigue syndrome and concluded lab tests used in the original study were unreliable, reported.
"The original findings that led to the concern and the excitement that this is real aren't reproducible," study author Dr. Michael P. Busch, professor of laboratory medicine at the University of California at San Francisco, said at the time. "I take that as an indication that those results are unreliable."
But researchers at Whittemore Peterson Institute still stood behind their original results, despite partially retracting some data,reported.
"Clearly things aren't over or they wouldn't be awarding grants for people like us to study this virus," Dr. Judy A. Mikovits, director of research at the Whittemore Peterson Institute, said at the time.
In Friday's issue, the journal says it has lost confidence in the report and so it is retracting it fully. In an unusual step, the retraction came from the editors rather than the authors, though editor-in-chief Bruce Alberts said most of the authors agreed in principle to retract the paper "but they have been unable to agree on the wording of their statement."
The news that scientists are no closer to finding a cause for the syndrome may disappoint some of the million-plus Americans who suffer from chronic fatigue. The disease is characterized by overwhelming fatigue for at least six months despite ample rest. The condition also causes weakness, muscle pain, impaired memory and/or mental concentration, and insomnia. Chronic fatigue syndrome can't be diagnosed with a simple test, so doctors diagnose it by ruling out other diseases. Women between the ages of 40 and 50 years old are most frequently diagnosed with the disease.
The CDC has more on chronic fatigue syndrome.