As I understand it, CFS will disappear and the patient pool will be split into two groups:
1) XMRV positive patients will be diagnosed with XAND disease and be placed under new leadership with increased public awareness and funding, sparking lots of research and epidemiology studies. Treatment trials with retroviral drugs will be initiated for patients.
2) Patients not XMRV positive will be diagnosed with a new major DSM IV psychiatric disorder; "Ideopathic Reeves Disease". They will still fall under Reeves purview and be shifted away from the CDC into a backwater program with absolutely no funding. It will have a catchy name like "Women's Hysterical Group for Unwellness Research"
But if another definition was used, say the Canadian ME/CFS definition, to be called ME/CFS for the rest of the E-mail.
There would XMRV+ ME/CFS and XMRV- ME/CFS. Scientists could probably still find interesting things in the XMRV- ME/CFS group.
But if a CFS (Reeves criteria) group is used, there would be:
XMRV+ CFS (Reeves criteria) and XMRV- CFS (Reeves criteria). The second group is going to be an extra huge mess for scientists to study.