A group of researchers says a higher basal body temperature made intestinal bacteria more active in mice and prevented them from becoming seriously ill with influenza.

The group includes Associate Professor Ichinohe Takeshi of the University of Tokyo's Institute of Medical Science. It released the results of its experiment in the British science journal Nature Communications.

The researchers took note that mice with high basal body temperatures are less likely to develop serious symptoms if they are infected with flu. They closely examined substances in the mice's blood.

They found that the amount of secondary bile acids, which work to suppress inflammation, increased significantly in the blood of mice with basal temperatures of 38 degrees Celsius or higher -- one degree above normal. The acids are produced by gut microorganisms.

The researchers say they also confirmed that more mice died from infection when the function of their intestinal bacteria was artificially suppressed even when the mice had higher basal body temperatures.

The researchers say the bacteria could also suppress severe symptoms caused by other infectious diseases, including the coronavirus.

Based on the results, Ichinohe said he wants to research the link between intestinal bacteria and severe symptoms in humans and develop new treatments.