Looks like the CDC’s chronic fatigue syndrome research group, led by Dr. William C. Reeves, may have some ‘splaining to do today in Washington. A possible research breakthrough — the discovery of a correlation between CFS and a retrovirus related to the AIDS virus — has fired up the medical community in recent weeks. “This is going to create an avalanche of subsequent studies,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University, told the New York Times this month. But will the Centers for Disease Control and Prevention play a role in that research? It hasn’t so far.