Because newborns don’t have an established gut microbiome — the collection of friendly bacteria that helps humans digest nutrients and respond to intestinal pathogens — they are especially susceptible to the norovirus, which is one of the leading causes of newborn deaths worldwide.

“We knew microbiota protected adult mice from norovirus infection and we knew newborns were vulnerable to severe norovirus disease,” said Stephanie Karst, Ph.D., a member of the UF Emerging Pathogens Institute and a professor in the UF College of Medicine, who led a recent mouse-model study on norovirus that was published on Aug. 29 in Cell Host & Microbe. “So, that led us to ask the question: Are newborns vulnerable to norovirus because their gut microbiota is immature?”