I don't know, but I (a wife, mother, housewife, non-scholar, non-expert) I do believe that this will turn out to be a real disease.
I like to follow these 2 links for updates:
http://www.freerepublic.com/focus/keyword?k=Morgellons
http://news.google.com/news?hl=en&ned=us&q=Morgellons&btnG=Search+News
I'm convinced it is a disease, I just have trouble believing that researchers haven't found a pathogen for it. Fungi, if memory serves, have life cycles that can manifest very different structure at different stages ... the athlete's foot we walk around with has a much larger and completely different appearance in another stage of its life cycle.