Hey, Scareface. How's it going. My theory, actually implies a unknown parasite that works like malaria [apicomplexan] which infects the inside of specific cells, opening a door for other normally harmless "agents" to become opportunistic, including candida in some cases. Again, it is all about the individual's biochemical state, which determines the extent of health alteration. I am sure, [like toxoplasma gondii] most people remain asymptomatic.
They say the french population are almost 100% infected with toxoplasma, because of their preference for under cooked beef.
Toxo, is a well studied parasite, but researchers admit, there may be many, many other similar parasites which have the potential to infect humans. Shroom