Research on the human virome (the extensive communities of viruses that persist in human tissue and blood) is exploding, thanks in large part to projects like the Joint Genome Institutes’s “Uncovering the Earth’s Virome” initiative. A large part of the human virome is comprised of bacteriophages, or viruses that infect bacteria (one study estimates that ~31 billion bacteriophages traffic from the human gut into the body on a daily basis). Even then, the vast majority of the human virome has yet to be identified and characterized. For more background on the human virome, watch this video I recorded on the topic. 

A bacteriophage (Medical News Today)

In 2018 more research teams began studying how the human virome impacts health and disease processes. Because phages modulate activity of the bacterial microbiome this is major consideration. These are several of my favorite 2018 papers on bacteriophages as drivers of disease:

Diagnostic Potential and Interactive Dynamics of the Colorectal Cancer Virome

Lead author: Pat Schloss, University of Michigan

The team used a range of molecular tools to evaluate differences in human colorectal cancer virus and bacterial community composition (they analyzed stool samples). When the bacterial and viral community signatures were combined, both bacterial + viral organisms were found to drive the community association with the cancer.

Paper highlight: “Overall, our data support a model in which the bacteriophage community modulates the bacterial community and, through those interactions, indirectly influences the  bacteria driving colorectal cancer progression”

Murine colitis reveals a disease-associated bacteriophage community

Lead author: Lora Hooper, University of Texas Southwestern Medical Center

The team characterized the intestinal virome in a model of T-cell-mediated mouse colitis. The intestinal phage population changed in the mice with colitis, and transitioned from an ordered state to a stochastic (disordered) dysbiosis. In addition, phage populations that expanded during colitis were frequently connected to bacterial hosts that benefit from or are linked to intestinal inflammation.

Smoking is associated with quantifiable differences in the human lung DNA virome and metabolome

Lead author: Brian Keller, The Ohio State University

The team found that commensal viruses are present in the lower respiratory tract and differ between smokers and nonsmokers. The associations between viral populations and local immune and metabolic tone suggest a significant role for virome-host interaction in smoking related lung disease.

Bacteriophages as New Human Viral Pathogens 

Lead author: George Tetz, Human Microbiology Institute, New York

The team presents evidence that phages can interact w/ eukaryotic (human) cells and proteins to drive inflammatory disease processes. They also point to mechanisms by which certain phages disrupt intestinal permeability and provoke chronic inflammation. For more on the paper and Tetz’s work in general, listen to my recent interview with George.