While viruses are commonly associated with illness, our gastrointestinal tract is home to a complex ecosystem of bacteria and viruses that interact with each other. While the role of gut bacteria in promoting health and protecting against chronic diseases later in life is well-established, our understanding of the many viruses found in the gut is still limited. Ongoing research is shedding light on the diversity and potential impact of gut viruses, especially in early childhood.
Yes, University of Copenhagen professor Dennis Sandris Nielsen and a team of researchers from COPSAC (Copenhagen Prospective Studies on Asthma in Childhood) and the Department of Food Science at UCPH conducted a five-year study, delving into the question of gut viruses in young children. They studied and mapped the diaper contents of 647 healthy Danish one-year-olds to better understand the diversity and potential impact of viruses in the gastrointestinal tract during early childhood.
The study led by Professor Dennis Sandris Nielsen found a significant number of unknown viruses in the feces of healthy Danish one-year-olds. These viruses represented over 200 families of previously undescribed viruses, indicating that young children have a diverse array of gut viruses that may influence their risk of developing diseases later in life. This research was published in the journal Nature Microbiology.
The researchers discovered and mapped 10,000 viral species in the feces of the one-year-old children, a number that is ten times larger than the number of bacterial species found in the same children. These viral species belong to 248 different viral families, with only 16 of them previously known. The researchers named the remaining 232 unknown viral families after the children whose diapers were studied, resulting in the naming of new viral families such as Sylvesterviridae, Rigmorviridae, and Tristanviridae. This highlights the vast diversity of gut viruses in early life that are yet to be fully characterized.
Bacterial viruses are our allies
The systematic overview of gut viral diversity conducted in this study is the first of its kind, providing new insights into the importance of viruses in the development of our microbiome and immune system. The researchers hypothesize that the high diversity of gut viruses observed in one-year-old children is necessary for protection against chronic diseases such as asthma and diabetes later in life. At this young age, the immune system may not have fully learned to distinguish between harmful and harmless viruses, leading to an exceptionally rich variety of gut viruses. This study sheds light on the potential role of gut viruses in shaping long-term health outcomes.
Bacteriophages, which make up 90% of the viruses found in the study, are viral species that specifically infect and replicate within bacteria. They do not attack the children's own cells and are not known to cause disease. The hypothesis is that bacteriophages play a beneficial role as allies, potentially helping to regulate the gut bacterial community and contribute to the development of a healthy microbiome in young children. Further research is needed to better understand the specific interactions between bacteriophages and gut bacteria, and their potential implications for human health.
Bacteriophages are believed to play a significant role in shaping bacterial communities and their function in the gut. Some bacteriophages can transfer genes to their bacterial host, which may provide the host with advantageous properties, such as increased ability to metabolize carbohydrates. Bacteriophages may also help maintain a balanced gut microbiome by regulating the populations of individual bacterial species, preventing overgrowth of any one species. This dynamic interaction between bacteriophages and gut bacteria is akin to the predator-prey relationship between lion and gazelle populations in the savannah. Further research is needed to fully understand the complex interplay between bacteriophages, bacteria, and the gut microbiome in human health.
Viruses, bacteria, and the immune system likely interact and affect each other in a delicate balance that can impact health and disease. Viruses, particularly bacteriophages, play a crucial role in shaping bacterial communities in the gut and maintaining a balanced gut microbiome. The remaining eukaryotic viruses, which infect human cells, are found in all children and may have a role in training the immune system to recognize infections later in life. However, their precise role and potential implications for disease risk are not yet fully understood and require further research.
The origin of the many viruses found in one-year-olds is not yet fully understood, but the researchers believe that the environment, including exposure during birth and later through contact with dirt, pets, and other factors, may be a likely source. The initial bacteria acquired during birth from the mother and environment could potentially introduce some of the first viruses, and subsequent exposures in the environment could contribute to the diversity of gut viruses observed in young children. Further research is needed to better understand the sources of these viruses in early life.
As Shiraz Shah points out, the entire field of research speaks to a huge global health problem:
The researchers are investigating the role of gut viruses in relation to various childhood diseases, including asthma and ADHD, as many chronic diseases are believed to have an inflammatory component related to immune system dysfunction. By understanding the role of bacteria and viruses in immune system development, it is hoped that this knowledge can potentially lead to strategies for avoiding or mitigating chronic diseases that affect many people today. Further research in this area is ongoing.
Virulent bacteriophages are a type of bacteriophage that infect bacteria, take over the bacterium's machinery to produce multiple new virus particles, and ultimately cause the bacterial cell to burst, releasing the newly produced virus particles into the environment. This process can help maintain the balance of the intestinal ecosystem by regulating the population of bacteria.
Temperate bacteriophages are a type of bacteriophage that can integrate their genetic material into the genome of the host bacterial cell and reproduce when the cell divides. This process can result in the transfer of new genes to the bacteria, potentially giving them a competitive advantage. However, an imbalance in the population of temperate bacteriophages has been suggested to be associated with various diseases, including inflammatory bowel disease and other conditions. Further research is needed to fully understand the complex interactions between temperate bacteriophages, bacteria, and their impact on human health and disease.
A virus is a tiny infectious agent composed of genetic material, either DNA or RNA, enclosed in a protein coat. Viruses are unable to reproduce on their own. Instead, they invade a host cell and hijack its machinery to replicate and produce copies of themselves.
Viruses are categorized into groups called viral families, which are further subdivided into numerous viral genera and viral species. One well-known viral family is the coronavirus family, which includes viruses such as Covid-19, MERS, SARS, and several common cold viruses (PB/Newswise)