While we are eagerly awaiting new research on the XMRV-CFS connection... It is often noted that it is not currently possible to "cure" retrovirus infections. It gets integrated into a persons DNA and they are stuck with it. At least for now. I found this interesting. In short, they corrected genetically caused color blindness in monkeys by infecting them with a custom-designed virus that changed the relevant portion of the monkeys' DNA. This makes me hopeful that someday, if XMRV is the real problem, there will be an unqualified "cure".