NEW YORK (AP) — A prestigious scientific journal is retracting a controversial 2009 report that linked chronic fatigue syndrome to a virus.

In an unusual move, the journal Science is taking that step on its own. Normally, authors retract their own research papers when serious problems arise after publication.

But Science has lost confidence in the report and the validity of its conclusions, editor-in-chief Bruce Alberts writes in Friday's issue. He said most of the authors have agreed in principle to retract the paper "but they have been unable to agree on the wording of their statement." A retraction signed by all the authors "is unlikely to be forthcoming," Alberts wrote.

The original paper, from scientists at the Whittemore Peterson Institute in Reno, Nev., and the National Cancer Institute, reported finding a virus called XMRV in blood cells of patients with chronic fatigue syndrome. That raised hope that a cause of the mysterious illness had been found.

But follow-up studies by other scientists found no evidence of such a link. Last May, Science published two reports suggesting the original finding was due to lab contamination.

At the time, Alberts published a statement declaring that the validity of the study was "now seriously in question."

Then in September, the authors retracted some of the data, citing contamination.

In his statement on the full retraction, Alberts said the authors had also acknowledged omitting important information about the study's procedures in an illustration of some lab results.

The Whittemore Peterson Institute is preparing a statement about the retraction, a spokeswoman said Thursday.