There are many illnesses that can leave you weak or unable to work. Some involve chronic pain. Others relate to fatigue. One in particular, Chronic Fatigue Syndrome, has left many frustrated, because it is notoriously difficult to diagnose and treat.

Even though the illness is more recognized in the medical community than it was 10 or 20 years ago, theories still abound about what causes it. New studies released recently, unfortunately, essentially eliminate one popular theory. It will likely bring researchers back to square one.

According to a Consumer Reports article, the theory was that Chronic Fatigue Syndrome is caused by a virus, XMRV, or xenotropic murine leukemia virus (MLV)-related virus. A 2009 study published in the journal Science apparently found the virus in over two-thirds of suffers of the illness who were examined. That was compared to just under four percent of people in good health.

However, new research seems to debunk that argument. Some disputed its methodology, and others speculated the results were skewed because of some sort of laboratory contamination. To top it off, three new studies show little or no link between the virus and the illness.

In two of the investigations, there was no detection of the virus in the white blood cells of patients, including some of the patients who were included in the 2009 study. Another study appears to support the idea that laboratory contamination affected the original study's results.

It's frustrating news for those who suffer from Chronic Fatigue Syndrome, because if a virus caused it, then patients could potentially be treated with antiviral drugs. Now the cause is still a mystery, and better treatment and prevention is not quite within reach.

Source: Consumer Reports, "For chronic fatigue sufferers, another blow," 22 June 2011