Chronic fatigue syndrome is not linked to suspect viruses
The causes of chronic fatigue syndrome (CFS) have long eluded scientists. In 2009, a paper in the journal Science linked the syndrome—sometimes called myalgic encephalomyelitis (ME)—to infection with a mouse retrovirus called XMRV (xenotropic murine leukemia virus (MLV)-related virus). Given that affected patients often have symptoms consistent with a chronic infection, this viral connection seemed plausible, and the findings were celebrated as a major achievement for a complex disease that afflicts nearly 1 million in the U.S. Another study in early 2010 published in Proceedings of the National Academy of Sciences detected murine retrovirus-like sequences (designated pMLV: polytropic MLV) in CFS/ME patients, which provided further support for a viral theory.