In 2000, the drinking water in the Ontario town of Walkerton was contaminated with E. coli O157:H7 and campylobacter.  7 people died, and roughly 2,300 suffered illness as a result.   The large number of people involved in the outbreak has provided doctors and scientists an opportunity to look at the long term impacts of foodborne illness. 

According to this report, studies on Walkerton survivors are now revealing genetic risk factors associated with the likelihood of developing post-infectious irritable bowel syndrome:

Of the 2,300 people who were sickened, 36 per cent developed post-infectious irritable bowel syndrome or PI-IBS.

Patients suffer from chronic abdominal pain and discomfort, bloating, and defecation problems that develop suddenly after an episode of acute gastroenteritis or inflammation of the stomach and intestines. Doctors diagnose PI-IBS after ruling out structural and biochemical abnormalities and other known disorders like Crohn’s disease or ulcerative colitis.

The study, which linked three particular genes to an increased risk of post-infectious irritable bowel syndrome, will be published in the March edition journal Gastroenterology.