Can a stomach bug cause long-term disease? From MS to cancer, new studies suggest the hidden danger of common infections

Research links common bugs to Crohn’s disease, multiple sclerosis and more. But it depends on genetics, and studies are being carried out to find out more

Scientists think long-term illnesses may be caused by an overreaction of some people’s immune system to certain bugs. Young women may be at a heightened risk

Reading Time:6 minutes

A bout of norovirus equals a few unpleasant days in the bathroom for most, but it may trigger Crohn’s disease in an unlucky few. Photo: Shutterstock

Published: 6:15pm, 8 Nov 2022

In most people, norovirus causes a few days of misery spent in the bathroom and then is quickly forgotten. Epstein-Barr virus can pass without any indication at all. And many people shrug off Covid-19.

But a growing body of research suggests that in some unlucky few, the immune system overreacts to these seemingly minor insults, leaving years or even a lifetime of symptoms.

“The wrong genetics with the wrong infection at the wrong time [can be dangerous],” says Dr Judith James, a rheumatologist and vice-president of clinical affairs at the Oklahoma Medical Research Foundation, in the United States. “I do think we have mounting evidence that means people should have this on their radar.”

It’s long been suspected that seemingly simple infections can leave a lasting imprint.

A 3D illustration of virus and bacteria cells infecting the human body. Photo: Shutterstock

New research found a likely connection between a bout of norovirus – more commonly known as a stomach bug, which tends to strike mostly in winter in Hong Kong – and Crohn’s disease, a long-lasting inflammatory bowel condition.

Other recent studies have blamed an Epstein-Barr infection on later multiple sclerosis, and as many as 10 per cent to 30 per cent of people who catch Covid-19 have symptoms that linger for months to years.