There is an emerging body of evidence that links microbes to many human diseases and conditions that are not inherently infectious. Such diseases and conditions I know of so far include any autoimmune disease (molecular mimicry is a huge topic here), allergies and other inflammatory disorders (a lack of microbes seems to be a concern rather than the presence of specific species here), cancers, obesity (too much gut yeast), and mental health disorders associated with my favorite pathogen Toxoplasma Gondii. I have also learned a fair amount about research being done on correlations between microbes and autism (leaky gut syndrome is apparently common in more intense cases of this neurology).
Just another blogs.oregonstate.edu site