Chronic fatigue syndrome may be caused by a virus

The connection viral gained notoriety when researchers from Nevada said they discovered a specific strain in the blood of two thirds of the 101 chronic fatigue patients studied.
A U.S. government study found a family of viruses that affects mice with chronic fatigue syndrome, which raises questions about whether the complicated disease may be related to an infection.
The study does not prove to have any of these viruses cause damage, said co-author Dr. Harve Alter of the National Institute of Health. But it reinforces that suspicion, and the government is conducting further investigations to determine if the link is real or not.
Meanwhile, a group of French and Canadian scientists said it was time to investigate whether new antiviral drugs such as those used for HIV can be treated at least some chronic fatigue patients and viruses.
The viral connection gained notoriety when researchers from Nevada said they discovered a specific variety, called XMRV, in the blood of two thirds of the 101 chronic fatigue patients studied. But several other studies, including one of the Center for Disease Contro and Prevention, did not detect the virus in patients XMRV, prompting researchers to ask whether it was a false alarm.

Chronic fatigue is caused by a virus

The study is published in the Proceedings of the National Academy of Sciences, thickens the mystery. This time, scientists from the National Institutes of Health (NIH) and the Food and Drug Administration (FDA) examined the blood of 37 patients with chronic fatigue and also found no XMRV, but instead found a group of a family of viruses MLV in 86% of cases.
Tests to 44 healthy blood donors, by contrast, found evidence of such viruses by almost 7%.
Several viruses have been linked to chronic fatigue over the years only to be ruled out as possible culprits of mysterious disease affecting a million people in the U.S.. It is characterized by at least six months of severe fatigue, memory impairment and other symptoms, but does not have a screening test or specific treatment.

These MLV, an acronym in English of "virus of mouse leukemia related to" cause some varieties of cancer in mice and has found the relative of XMRV in some prostate tumors in humans.
But there is no simple way to detect it, which means that studies of a possible link at this point to be made in research laboratories and in doctors' offices, researchers at the FDA and the NIH on Monday.
No one knows how to infect humans, but Alter said it is conducting a large study to see if there is evidence of transmission through blood.
Meanwhile, federal regulators require that blood donors are healthy, said Dr. Hira Nakhasi, the FDA.