Considering how similar Gulf War Syndrome is to CFS, it leads me to postulate that time will reveal they are the same illness - different identity. How do I come up with this hypothesis - a large number of soldiers who served in Iraq during Desert Storm have been diagnosed and treated for Leishmaniasis - a sandfly borne disease. The tagline in the movie Casablanca reads "Round Up The Usual Suspects" - Mosquitoes and Ticks are not endemic in the desert - so what is left - Sandflies! Maybe even Leishmania is a vector for XMRV?
Battle fatigued soldiers are often immunocompromised from stress - and then a bite from an infected sandfly - you've got the perfect storm to set XMRV related disease in motion. Out the window goes the hypothesis of spent uranium, exposure to toxins, and prophylactic use of Pyridostigmine Bromide as an antidote. Most chemical warfare agents are Organophosphates, which also include common pesticides such as Diazinon, Malathion, Guthion - the effects of poisoning which do not resemble CFS symptoms at all, and Pyridostigmine Bromide is used as a treatment for Myastenia Gravis and to treat orthostatic hypertension - a complaint of CFS patients!