A federal study has found that there is no link between viral infection and chronic fatigue syndrome, bringing a three-year saga to a close.

In 2009, a paper in the journal Science found a connection between chronic fatigue syndrome, also called myalgic encephalomyetis (ME), and a mouse retrovirus called XMRV, xenotropic murine leukemia virus (MLV)-related virus. A retrovirus copies its own genes into the DNA of the host.

The study created excitement that researchers would be able to develop therapies for the disease, which has no known cause or cure for the 1 million people who suffer from the disease. Many CFS patients feel that their condition is not taken seriously by the medical community.

But, in a study published today in the scientific journal mBio, researchers from the National Institutes of Health, the Centers for Disease Control and Prevention, and Columbia University said that they found no evidence of infection in the blood of 293 participants, half of whom had CFS and half of whom were matched controls. The participants ranged in age from 18 to 70, and controls were matched with the disease sufferers according to age, gender, race and geographical location.

The results of the study were expected.

Many in the scientific community saw the writing on the wall when Science retracted the paper in December because the results were unable to be replicated by numerous laboratories. It is now believed that the findings of the original, controversial paper came about due to lab contamination.

The initial findings led to the American Red Cross barring people with CFS from donating blood. That ban still stands, but may be reconsidered.

Though researchers were unable to find the cause of chronic fatigue syndrome with this study, they are content that they have a huge bank of blood samples from people with the disease - something doctors and scientists did not have before. They believe that they will be able to study the disease more.

CFS is characterized by muscle and joint pain, severe fatigue, as well as memory and concentration problems.