" Scientists have uncovered a never-before-seen class of virus-like entities hiding in the human gut and mouth, and these "viroids" may influence the gene activity within the human microbiome, Science reported . The researchers confirmed one host for these viroids, namely, a common bacterium found in the mouth called Streptococcus sanguinis . They've yet to confirm additional hosts, but they suspect at least a fraction are bacteria." For more details: Mysterious virus-like 'Obelisks' found in the human gut and mouth and here: https://www.science.org/content/article/it-s-insane-new-viruslike-entities-found-human-gut-microbes