If indeed a retrovirus turns out to be the linchpin of ME, could we expect that it's non-prevalent in the healthy controls, or would it be found in plenty? I am taking the latter position, and while (needless to say) much is uncertain, I'll explain why I am making that assumption. Looking at how ME gets triggered, should give some clues as to what's the root cause of the syndrome. Time and time again one hears stories about people getting a full blown case of ME after a case of mononucleosis, giardisis, or a normal flu. The point isn't that these three are «the» triggers, the point is that many widely different things can trigger the condition known as ME. Although contested, some would add vaccination and lyme disease to the list as well - but again, if those are some of the triggers or not is not the point I am making - the point I am making is that the triggers can be a variety of things which it seems all have in common that they give the immune system a larger workload for a short period of time. Triggering what. If a retrovirus is found to be at the core of ME, one would expect that what the triggers does, is to trigger the virus. Making it go from latent to full blown. With regards to the most famous retrovirus, there are different stages of the disease, and the first stage of the retrovirus becoming active often times begins with a flu like feeling, swollen lymph nodes and general malaise. Latent to active. First, if a trigger is to send a retrovirus from latent to active, the retrovirus has to be in the body of the patient before the triggering event. Given that so many of the ME cases begin with a trigger, the natural conclusion would be that the retrovirus has to lie latent in many healthy people, and with some percent of them, a mononucleosis, flu or giardia infection is the only thing needed to trigger the virus. Retroviruses and the immune system. If a retrovirus is at the core, it's not unlikely that it can cause havoc in the immune system. We know the ME syndrome doesn't include immunodeficiency like HIV infection does, instead the new Mella & Fluge study points towards autoimmunity playing a major role in ME, and knowing what other retroviruses can do to the immune system, it's not unlikely that a ME retrovirus could mainly cause a autoimmune reaction. This would also explain why the Mella & Fluge results show that as long as people are on the immune suppressors, many improve. But once they're off, relapses are common. Routes of transmission. Although different infections behave differently, one would expect that if it's exogenous we'd have somewhat of an idea of which route of transmission the virus takes. When catching an exogenous infection, it often times (but far from always) begins with symptoms of acute infection, which would help identify a route of transmission. To me, this points more towards a retrovirus (if indeed at the core of ME) being endogenous rather than exogenous. The gender explanation. Women have two X chromosomes, men have one. A theory of what's behind ME must seek to explain why the disease is more prevalent with women than men. Some of the most distinguished retrovirologists working with endogenous viruses points towards copies of endogenous retroviruses being present in the X chromosome as a potential cause for the prevalence difference. What I am posting the thread for is not to state how things are, but rather to open a debate as for reasons why a potential ME retrovirus would be (or not be) prevalent in healthy controls, and also whether or not it's endogenous. I'd like to hear from you, about what your thoughts are, and how you think the dots connect.