Researchers have identified more than 140,000 viruses that live in the human gut, including half that were previously unknown.
The number and variety of viruses found in more than 28,000 gut microbiome samples gathered from different parts of the world are surprisingly high, according to the study authors.
The researchers added that their findings will lead to new research to learn how gut viruses affect our health.
In the age of COVID, "it's important to remember that not all viruses are harmful, but represent an integral component of the gut ecosystem. For one thing, most of the viruses we found have DNA as their genetic material, which is different from the pathogens most people know, such as SARS-CoV-2 or Zika, which are RNA viruses," explained researcher Alexandre Almeida. He's a postdoctoral fellow at the Wellcome Sanger Institute and EMBL's European Bioinformatics Institute.
"Secondly, these samples came mainly from healthy individuals who didn't share any specific diseases. It's fascinating to see how many unknown species live in our gut, and to try and unravel the link between them and human health," Almeida said in a Wellcome news release.
There is great biodiversity in the human gut. Along with bacteria, it contains hundreds of thousands of viruses called bacteriophages, which can infect bacteria.
Imbalances in your gut microbiome can contribute to diseases and conditions, such as inflammatory bowel disease, allergies and obesity. However, much remains to be learned about how gut bacteria, and the bacteriophages that infect them, affect your health.
According to study senior author Trevor Lawley, also from the Wellcome Sanger Institute, "Bacteriophage research is currently experiencing a renaissance. This high-quality, large-scale catalogue of human gut viruses comes at the right time to serve as a blueprint to guide ecological and evolutionary analysis in future virome studies."
Among the tens of thousands of viruses discovered by the researchers was a new highly prevalent clade (a group of viruses believed to have a common ancestor), which the authors refer to as the Gubaphage. It's the second most common virus clade in the human gut, after the crAssphage, which was discovered in 2014.
Both clades seem to infect similar types of human gut bacteria, but further research is needed to pinpoint the exact functions of the newly discovered Gubaphage, the study authors said.
The Harvard School of Public Health has more on the microbiome.
SOURCE: Wellcome Sanger Institute, news release, Feb. 18, 2021