Bacteriophages (bacterial viruses) attached to a bacterial cell wall.
A review in the journal Cell written by Herbert Virgin describes the exploration of the virome, a part of the overall microbiome which includes viruses, as an emerging study of importance in relation to human health. The size of the mammalian virome –viruses that infect mammals- is still unknown, but it is believed by scientists that, in the human body, viruses may outnumber the bacterial microbiome by at least 10x, making the virome out number human cells by 100 times or more.
The human virome includes all the viruses that affect human cells, along with those that affect our bacterial, archaeal, and fungal microbiome, in addition to other viral derived genetic material. Viruses have already been studied as important pathogens for each of these hosts, but their mutualistic and beneficial interactions are only beginning to be explored. This is similar to the story of bacteria, which are only now being recognized for their importance in humans. In addition, it appears there are many important, complex interactions within the microbiome that include the virome. For example, it is likely that viruses that attack bacteria are embedded in the gut mucous and attack and destroy bacteria before the bacteria can reach the gut lining, providing host immunity.
Investigation into the viral microbiome is still at its beginning. Discovery of new viruses and their interactions with humans is likely to continue and perhaps increase with the increase in availability of viral genome information. We encourage everyone to read the linked article. The virome is a fascinating subject which we hope to explore in future blog posts.