Across a series of mouse experiments the researchers demonstrated how a norovirus infection can bring on Crohn's disease.

Crohn's disease is a chronic inflammatory condition that is generally diagnosed in young adulthood. The causes of Crohn's are unknown but it is strongly suspected to be triggered by a combination of genetic, environmental and microbial factors.

More than 30 different genetic variants have been linked to increased Crohn's disease risk. However, one particular variant, in a gene called ATG16L1, has been particularly associated with the disease.

This gene plays a role in cells that line the gut, but not everyone with this gene variant goes on to develop Crohn's. In fact, around half of all Americans carry this specific mutation, yet only a fraction will be diagnosed with the inflammatory disease.