Scientists have uncovered a strong link between an unusual virus and chronic fatigue syndrome, which affects more than 1 million people in the United States. Researchers found that two-thirds of people with chronic fatigue are infected with a retrovirus called XMRV, according to a new study in the journal Science Express. XMRV has also been found in the tumors of some prostate cancer patients. Scientists say it's too soon to say whether XMRV actually causes chronic fatigue. People with the syndrome feel tired even after a good night's sleep. Many also have debilitating pain in their muscles or joints, trouble concentrating and immune problems.
The story is on NPR here.