title: [Outbreak of food-borne Norovirus associated with the consumption of sandwiches].
abstract: OBJECTIVE
  The aim of this study was to conduct an investigation into an outbreak of food-borne disease at a hotel, when epidemiological and microbiological results determined that the etiological agent was Norovirus and the source of infection was food handlers.
  
  
  METHODS
  We detected an outbreak of gastroenteritis in a group of 59 students and teachers from a secondary school who were staying at a hotel in Espot, Lleida (Spain). A historic cohort study was conducted into the consumption of water and food and clinical symptoms were also analyzed. We studied the water supply and various food items. Faecal specimens from 14 patients and four food handlers were cultured and examined for Norovirus by PCR-RT. The influence of each foodstuff was assessed by relative risk (RR) at 95% confidence intervals.
  
  
  RESULTS
  We interviewed 96.6% of the patients (57/59). The overall attack rate was 66.7% (38/57). The median period of incubation was 25.0 hours (maxim 59 and minimum 19 hours). Symptoms included abdominal pain 94.7% (36/38), vomiting 86.8% (33/38), nausea 76.3% (29/38), diarrhoea 52.6% (20/38) and fever 48.6% (17/35). Of the four different kinds of drinking water and 13 food items studied, the only significant factor was the consumption of sandwiches (RR = 2.3; CI 95%, 1.1-5.1). Cultures were negative for bacteria. PCR-RT tests were positive for Norovirus in 12 of 14 faecal samples. There were also positive results for the same virus in two of four faecal samples from food handlers, although neither of them presented clinical symptoms.
  
  
  CONCLUSIONS
  This research highlights the fact that food-handlers should always be investigated in the case of outbreaks of food borne Norovirus. They must strictly follow hygiene rules, especially when they produce food that is to be eaten without any form of cooking.
authors.affiliation: Servicios Territoriales, Departamento de Salud, Lleida, Spain.
authors.forename: Pere
authors.initials: P
authors.lastname: Godoy
authors.forename: Joan
authors.initials: J
authors.lastname: Izcara
authors.forename: Rosa
authors.initials: R
authors.lastname: Bartolomé
authors.forename: Pilar
authors.initials: P
authors.lastname: Bach
authors.forename: Amalia
authors.initials: A
authors.lastname: Escobar
authors.forename: Maria
authors.initials: M
authors.lastname: Pal
authors.forename: Gemma
authors.initials: G
authors.lastname: Codina
authors.forename: Joan
authors.initials: J
authors.lastname: Torres
authors.forename: Angela
authors.initials: A
authors.lastname: Domínguez
mesh_terms: D000293:Adolescent; D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology*; D004196:Disease Outbreaks; D005260:Female; D005511:Food Handling; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008297:Male; D029322:Norovirus / Q000302:isolation & purification*; D012147:Restaurants; D013030:Spain / Q000453:epidemiology