This is an older pdf from Milton Wainwright which gives a beautiful introduction to the wonderfully suppressed world of tiny pleiomorphic bacteria, Cell wall deficient forms, viruses, L-forms, nanobacteria, whatever the hell you want to call the phenomena.
http://mic.sgmjournals.org/cgi/reprint/145/10/2623.pdf
It's a shame how undeveloped the biology is in this field. However, the Marshall Protocol offers chronic disease sufferers an easy way to acknowledge CWD forms and follow a rigorous Th1 protocol to full remission. There are earlier blog posts here with much evidence concerning these forms.