[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. Lordsdale variant strain of Norovirus was detected from both of the well water and the feces of patients and staff. The well supplying to the guesthouse was only 10 meters deep and fecal coliform group was also detected in the well water from the guesthouse. This suggested that the water source was contaminated by human feces.