Dr Hyde says there is primary ME (enterovirus), and secondary ME from parvovirus and other infectious agents or chemical exposure. So he's not excluding any main recognized causes, from what I know. Since he is 80'years old now, he is trying to spend the rest of his meaningful life to help as many people as he can. He is currently trying to educate the medical community by sharing his knowledge and material. He is also still doing conferences. And he sees patiens in North America and Europe. Nobody can do it all. We're lucky he's still seeing patients at his age. I agree it would have been interesting to have specific research on the subject, though.