Dirty diapers from Danish babies revealed new viruses and the most complete depiction of the microbiota in infant bowels.
An international group of researchers has published their findings in the journal Nature Microbiology. They state that they discovered 10,000 new viruses in the excrement of infants. The researchers looked at the stool samples of 647 healthy Danish infants who were participating in a long-term study on asthma and chronic inflammatory diseases. The soiled diapers of the children provided a startlingly varied collection of viruses, many of which have not yet been identified by scientific research. In total, the researchers found 10,000 different viral species belonging to a total of 248 viral families. Of those families, only 16 were previously recognized.
In the children's feces, there were ten times as many viruses as there were bacterial species. Ninety percent of the viruses were bacteriophages, which prey on bacteria rather than human cells. There is no evidence that these bacteriophages cause disease; rather, it is believed that they alter the competitive capacities of bacteria and maintain a balance of bacterial populations within the microbiome of the gut.
Why are there so many viruses in the digestive tracts of children to begin with?
"Our hypothesis is that, because the immune system has not yet learned to separate the wheat from the chaff at the age of one, an extraordinarily high species richness of gut viruses emerges, and is likely needed to protect against chronic diseases like asthma and diabetes later on in life," Shiraz Shah, a senior researcher at the Copenhagen Prospective Studies on Asthma in Childhood and the study's first author, said in a news release. Shah was also the lead author of the study. Amandaviridae, Benjaminviridae, and Irisviridae are some of the newly discovered viral families that were given their names by the researchers in honor of the 232 infants who participated in the study.
