In fact, the people who've made a CAREER of researching CFS have plenty of answers, but they are not the ones CDC wants to hear.
There are 2000+ medical studies worldwide (as counted by Dr. Komaroff of Harvard) proving various biological/physical/organic causes. Since the
1975 Mercy San Juan epidemic, CDC has repeatedly dismissed any notion that there's a virus involved. "Epidemic" means it spreads like wildfire through the community ... it's not just a few people with wonky genes -- it's some sort of infectious agent or toxic substance. Something like 85% of patients report their symptoms starting with a flu-like illness (and because CDC has not acknowledged that there is any blood test which might sort this out, the other 15% may be misdiagnosed and have something else entirely).While you could argue that Lyndonville, being a small rural town, was probably filled with inbred people who all shared the same genes, the Mercy San Juan Hospital epidemic (like the Royal Free Hospital epidemic before it) was primarily unrelated people, doctors and nurses, who all got sick at the same time. People of all ages, all ethnic groups, not sharing many genes.
I had never heard of CFS (well, actually at that time CEBV) before I got sick. For several years afterward, I never met anyone else who had it (though I did have a report that a co-worker's cousin, in another state, "had that same really bad flu you did, and also never got better". One theory was that several times a week, I rode the bus with a nurse who worked in the office of the guy who became my CFS doctor -- possibly she was "wearing" the bug from a patient and sat next to me while the virus on her hands/clothing was still alive.
So, if I hadn't heard of CFS (as many patients hadn't) before getting sick, that shoots down the "mass hysteria" aspect that CDC has also used to try to explain this away. During the Incline Village outbreak, a large number of patients were teachers/students at Truckee High School. Aha!, saith CDC, mass hysteria. But other people were sick, people who knew nothing about what was going on at the high school. Minor detail, CDC managed to ignore it, along with most of the rest of the medical information presented to them by the doctors treating these hundreds of patients.
"Osler's Web" by Hillary Johnson (a journalist, not a patient with an agenda) is a really good explanation of all the medical evidence that CDC refused to acknowledge in the Incline Village epidemic.
CDC still says there's no test, no objective evidence of impairment; in the mid-80s, those doctors had already found that MRIs show a distinctive pattern of brain lesions -- you can't fake that, but CDC didn't want to hear it. They wanted to say it was depressed menopausal women and simply hushed up any evidence of men and children with the disease, and have continued to hush up the 2000+ studies that show viral damage, cardiomyopathy, blood abnormalities, etc.
If you talk to the researchers (who are medical doctors for the most part), they will tell you more than you want to know about blood tests which (while they don't specifically diagnose CFS) show objective evidence that patients have reduced Natural Killer cells, R Nase-L abnormalities, etc., objective tests that show neurological abnormalities or viral damage, etc. If you can put together bunch of these tests, each of which find abnormalities common to several diseases (i.e., don't specifically diagnose any one of them), you're left with a combination of results that can't be anything but CFS. Yet, CDC continues to promote the notion that there's no way to test for any of the things that go wrong in CFS.
In writing her book, Hillary Johnson read the original CDC memos, and saw in their own words that their goal was to minimize this illness so that the government and insurance companies wouldn't have to pay disability benefits. Clearly, that's still their goal, when they have studies that prove GENETIC problems, and twist those around to say that it's "just stress". In their press conference, they did everything they could to avoid talking about the defective genes and to continue to talk about purely psychological factors. They call their research "the first evidence of biological problems", dismissing 2000+ prior studies worldwide, like if we don't talk about them, they don't exist.
Over the past year, a number of former US government scientists, from various departments, have come forward and said they were ordered to cover up certain research that didn't say what their superiors wanted. It appears that CDC is one of those agencies which provides disinformation. Of course, the doctors working with CFS have known that for 20 years.....