In developed countries the most common bacterial cause of gastroenteritis is campylobacter infection. Most of these infections are sporadic and known risk factors include drinking unpasteurised milk or untreated water, eating chicken, barbecuing, and living or working on a farm. Several community outbreaks of campylobacter gastroenteritis arising from contamination of the water supply have been described but the mechanism of water contamination has usually been unknown. Now an outbreak in a rural community in southern Finland has been traced to a non-chlorinated well water supply.

In August 2000 there were 463 known cases of gastroenteritis …