A new intestinal virus identified

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Study identifies a new virus that lives in the human gut. Tom Werner / Getty Images
  • Scientists have extensively studied the identity and roles of human gut bacteria.
  • However, research on human intestinal viruses is lagging behind.
  • In a new study, scientists identify a new virus that could have a significant influence on human health and disease.

The human gut microbiota, including bacteria, fungi and viruses, is a major player in human health.

Scientists have extensively studied the effects of imbalances in gut bacteria. Several conditions, including obesity, Diabetes, Cancer, inflammatory bowel disease, and neurological diseases, all have associations with an imbalance between these bacteria.

While researchers are still working on the details, there is no doubt that these microorganisms have a complex connection to health and disease.

Health experts know much less about viruses, called intestinal virobiota, which exist in the human gut. A recent study published in mSystems have studied and identified many viral genomes found in humans around the world.

Most viruses residing in the human intestine are called bacteriophages or phages. These viruses require a bacterial host to reproduce.

Scientists have linked this close association between bacteria and viruses to many diseases, such as liver disease and some forms of cancer.

“It is therefore important to shed more light on the virobiota and its collective genomes called virome, as this will pave the way for the discovery of the complex interactions within the gut microbiota and their effects on the human host”, state the authors . of this study.

Studying the intestinal virome is no easy task. Phages appear to be quite diverse and somewhat unique in each individual, according to study principal investigator Jelle Matthijnssens, Ph.D., professor at the Viral Metagenomics Laboratory at KU Leuven in Belgium.

The individuality of intestinal viromas appears to be influenced by geographic origin, age, diet and health status.

In addition, the intestinal virome is a relatively new area of ​​study. Because this research is in its infancy, scientists have yet to identify and categorize the majority of these phages.

The researchers analyzed 254 fecal samples from 204 Danish participants, including children and adolescents aged 6 to 18 and adults aged 40 to 73. The study team used the Novel Enrichment Technique of Viromes protocol to purify stool samples and sequence their genomes.

From this data, the researchers developed the Danish Catalog of Enteric Viromas, or DEVoC. According to the authors, DEVoC is “the largest catalog of human intestinal viromes generated from consistently processed fecal samples.”

Using DEVoC, they compared 91 healthy intestinal viromas from the study population.

While most phage genomes were unique to individuals, 39 were present in more than 10 healthy participants. Three of the 39 most common genomes appeared to be associated with age.

The team then cross-checked the study results with global virome data. Two of 39 phage genomes – the crAss-like phage and LoVEphage – showed remarkably high prevalence worldwide, at 20.6% and 14.4%, respectively.

The researchers identified one as a crAss-like phage belonging to the AlphacrAssvirinae subfamily, which also includes herpes simplex viruses 1 and 2. The other was a previously undescribed phage, which they nicknamed LoVEphage because it encodes “a lot of viral elements”.

“Our discovery of the wide distribution of this new phage raises interesting questions regarding [phages’] role in the human gut microbiota and potential implications for human health and disease ”, said Professor Matthijnssens in an interview with Medical News Today. He continued:

“The vast majority of genes encoded by these new phages have unknown functions, making it difficult to predict how they might influence their bacterial host and the human host.”

MNT also spoke with Anthony William Maresso, Ph.D., professor at Baylor College of Medicine in Houston, TX, about the study. He said:

“One of the strengths of this study is the examination of viral signatures from many different subjects. It shows how somewhat individualized the virome is, much like what was found for the Human Microbiome Project. There also appears to be an association with age, and a new phage not described in great abundance has been described.

“In this area,” Prof Maresso continued, “which only scratches the surface, we are learning just how infinitely complex and diverse the total phage virome is. The next frontier in this field will be the development of ways to harness the functional power of this cryptic genosphere to improve our understanding of molecular medicine, cell biology, predator-prey ecology, and protein enzymology.

Speaking on future research, Prof Matthijnssens explained that “it would be very interesting to further research human stool samples for the presence of this phage as well as their genetic parents, and to further characterize their interactions with their host bacterial”.

The study of the virome is still in its infancy, but fascinating discoveries will certainly exist just beyond the horizon.

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