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Scientists identify thousands of unknown viruses in babies’ diapers


Research involving Danish babies’ dirty diapers has provided a plethora of information on previously unknown viruses — and the best view yet of the makeup of the infant gut microbiome.

Writing in the journal Nature Microbiology, an international team of researchers reports it has uncovered 10,000 new viruses in infant feces.

The study looked at the feces of 647 healthy Danish 1-year-olds enrolled in a long-term asthma and chronic inflammatory disease study. The kids’ dirty diapers yielded a surprisingly diverse set of viruses — many of which have yet to be described by science. Overall, the researchers uncovered 10,000 viral species from 248 viral families; of those families, just 16 were already known.

The viruses were 10 times more abundant than the bacterial species in the children’s feces; 90 percent of them were bacteriophages, which attack bacteria instead of human cells. These bacteriophages don’t cause disease; instead, they are thought to shape bacteria’s competitive abilities and balance bacterial populations within the gut’s microbiome.

Why are so many viruses in kids’ guts 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.

The researchers named the newly identified viral families after 232 of the participating infants themselves, including Amandaviridae, Benjaminviridae and Irisviridae.