We report an outbreak of viral gastroenteritis linked to municipal  drinking water in a town in northern Italy in June 2009.
An outbreak of viral gastroenteritis has been microbiologically  linked to a contaminated municipal water supply in a small town  of Lombardy.
In Italy, municipal water systems have been identified as the source  of water-borne infections in several norovirus outbreaks.  
On 9 June 2009, a general practitioner from the municipality  of San Felice del Benaco notified to the local health authority of  Brescia (Lombardy region, north Italy) 21 cases of gastroenteritis  among guests of a hotel.
The alert came from a cluster of gastroenteritis in a hotel.
Over  one month we identified 299 probable cases of whom 30 were  confirmed for at least one of the following viruses: norovirus,  rotavirus, enterovirus or astrovirus.
A total of 299 persons fulfilled the outbreak case definition,  including 269 probable and 30 confirmed cases.
Four cases were hospitalized,  all of them children.  
The attack rate for the town of San Felice del Benaco was 8.9%  (299/3,360).
Over  one month we identified 299 probable cases of whom 30 were  confirmed for at least one of the following viruses: norovirus,  rotavirus, enterovirus or astrovirus.
Water samples and filters from  the water system also tested positive for norovirus and enterovirus.
A confirmed outbreak  case was defined as a person who fulfilled the criteria of a probable  case and whose stool sample was laboratory-confirmed for at least  one of the following viruses: norovirus, rotavirus, enterovirus or  astrovirus.
Patients presented with vomiting,  diarrhoea and fever.
On 16 June 2009, preliminary environmental  investigation results showed abnormally high levels of Clostridium  perfringens (4 UFC/100 ml) and Aeromonas hydrophyla (16  UFC/100 ml) in water samples from two public fountains.
We report an outbreak of viral gastroenteritis linked to municipal  drinking water in a town in northern Italy in June 2009.
An outbreak of viral gastroenteritis has been microbiologically  linked to a contaminated municipal water supply in a small town  of Lombardy.
Active case finding was performed as follows: a public hotline was  set up where people could call the health authority for information  regarding the disease and report symptoms, date of onset and  basic demographic data. 
In parallel, the outbreak investigation  team collected daily information on case-patients presenting at the  emergency unit of the local hospital and collected stool samples  when possible.  
The local and regional health authorities initiated an  environmental investigation at the hotel on 9 June 2009, taking  food samples from the kitchen, interviewing and collecting stool  samples for microbiological testing from 20 probable cases (both  guests and hotel staff).
When it was clear that the outbreak was  spreading to the larger community (apart from three campsites with  their own private water supply, where no cases were reported), the  environmental investigation was extended and included collection  of water samples from the municipal water supply.
Over  one month we identified 299 probable cases of whom 30 were  confirmed for at least one of the following viruses: norovirus,  rotavirus, enterovirus or astrovirus.
The outbreak occurred between 8 June and 4  July 2009 and peaked on the 15 and 16 June with 47 outbreak  cases per day.
Control measures included treating the water system with chlorine  dioxide and filters with peracetic acid, while providing temporary  alternative sources of drinking water to the population.
On 17 June 2009, a special ordinance from the municipality  restricted the use of municipal water (inhabitants were told not  to use municipal water for drinking and cooking purposes) and  provided alternative water supplies to the population via water  tankers. 
Local authorities organized a door-to-door information  campaign and distributed leaflets in order to reach as many people  as possible. On 19 June 2009, the municipality started disinfecting  the water system with chlorine dioxide (0.2 mg/l) and sand filters  with peracetic acid.
Regular water  sampling and testing was performed to monitor the efficiency of  control measures.
Samples were sent  to the Lombardy and Emilia Romagna Experimental Zooprophylactic  Institute (IZSLER) to test for the presence of bacterial pathogens  (Salmonella sp., Shigella sp., Campylobacter sp., E. coli O157,  Yersinia enterocolitica, Aeromonas sp., Clostridium perfringens  toxins), parasites (Cryptosporidium sp.) and viral pathogens  (norovirus, rotavirus, enterovirus, astrovirus).
Stool samples obtained from 36 probable  cases were examined at the laboratory.
The mean age of confirmed cases of rotavirus was 29 years  (range: 0-71) compared to the mean age of 39 years (range: 0-88)  for cases of norovirus and 39 years (9-88) for cases of enterovirus.  


{'answer_start': [1213], 'text': ['norovirus,  rotavirus, enterovirus or astrovirus.']}