[Food borne outbreak caused by the well water contaminated norovirus].

In May 2004, 65 people from 18 groups of visitors to guesthouse (a traditional Japanese guesthouse) in the Nagano Prefecture, Japan developed acute gastroenteritis. Although these cases originally attributed to food poisoning, based on epidemiological and dietary surveys, there was nothing that is associated as a cause food. The same wall water was used throughout the guesthouse except in the kitchen, so testing was conducted on this water.