Hypothesis I got (not facts).
I am actually beginning to think (emphasis on think) more and more that we're dealing with a virus which primarily resides in the gut. It could very well be exceptionally hard to detect in blood, because it's reservoir is in the gut. The reason why these illnesses the virus is causing (FMS, CFS, MS, RA etc) have begun getting prevalent in the last part of the previous century is the radical change in diet. Because of the diet change, we now have a gut flora which makes it possible for these viruses to break out, previously the people of US/Europe and other Western countries had a protective gut flora prohibiting it from happening (because the diet was totally different). Now the RNA virus can break out from latent to active if it only gets a trigger (EBV, vaccine, etc). Because of the reactions people are getting to ARVs (both negative and positive) I am assuming it's a RNA-virus. And the virus can cause severe distortion of the immune system, which in turn causes severe symptoms. I am guessing if it is so, than there are either various viruses within the same group causing the different symptoms, or it's genetic differences between people causing them to get one over the other.
