Outbreak of viral gastroenteritis due to drinking water contaminated by Norwalk-like viruses.

Heinävesi, a Finnish municipality with a population of 4860 inhabitants, had an outbreak of gastroenteritis in March 1998. On the basis of an epidemiologic survey, an estimated 1700-3000 cases of acute gastroenteritis occurred during the outbreak. Municipal water consumption was found to be associated with illness (risk ratio [RR]=3.

Waterborne outbreak of viral gastroenteritis.

A waterborne epidemic took place in a Finnish municipality in April 1994. Some 1500-3000 people, i.e.