Many people with chronic fatigue syndrome are infected with an obscure virus that may cause, or at least contribute, to their illness.
The syndrome, which causes prolonged and severe fatigue, body aches and other symptoms, has long been a mystery ailment, and patients have sometimes been suspected of having psychiatric problems rather than physical ones. Worldwide, 17 million people suffer from the syndrome.
An recent study reports that 68 of 101 patients examined with the syndrome, or 67 percent, were infected with xenotropic murine leukemia virus-related virus, or XMRV. By contrast, only 3.7 percent of 218 people without chronic fatigue were infected. Continuing work after the study was published has found the virus in nearly 98 percent of about 300 patients with the syndrome.
XMRV is a retrovirus. These viruses carry their genetic information in RNA rather than DNA, and they insert themselves into their hosts’ genetic material and stay for life.