title: A norovirus GII.P21 outbreak in a boarding school, Austria 2014.
abstract: OBJECTIVE
  An Austrian boarding school reported a cluster of gastroenteritis on January 10, 2014. Environmental swabs from the school cafeteria and a nearby kebab restaurant tested positive for norovirus. The outbreak was investigated to identify its source(s).
  
  
  METHODS
  An outbreak case was defined as a student or staff member with diarrhoea or vomiting that developed between January 7 and 13. Details on food exposure were collected via a self-administered questionnaire; risk ratios (RR) and 95% confidence intervals (CI) were calculated. Norovirus from the stool specimens of cases and asymptomatic kebab restaurant workers were genotyped.
  
  
  RESULTS
  Twenty-eight cases were identified among 144 persons (attack rate 19%). The outbreak emerged and peaked on January 9, and ended on January 12. Compared to those who did not eat kebab, those who ate kebab on 7, 8, and 9 January were respectively 11 (95% CI 4.2-28), 6.7 (95% CI 3.4-13), and 9.3 (95% CI 4.0-22) times more likely to develop disease within the following 2 days. Stool specimens from three cases and three restaurant workers were positive for norovirus GII.P21.
  
  
  CONCLUSIONS
  The kebab prepared by norovirus-positive restaurant workers was the most likely source of the outbreak. It is recommended that food handlers comply strictly with hand hygiene and avoid bare-handed contact with ready-to-eat food to minimize the risk of food-borne infection.
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Währingerstraße 25a, 1096 Vienna, Austria; The European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control, Stockholm, Sweden.
authors.forename: Yung-Ching
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Public Health Authority, Carinthia, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hipfl
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Währingerstraße 25a, 1096 Vienna, Austria.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Lederer
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Währingerstraße 25a, 1096 Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Allerberger
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Währingerstraße 25a, 1096 Vienna, Austria. Electronic address: daniela.schmid@ages.at.
authors.forename: Daniela
authors.initials: D
authors.lastname: Schmid
mesh_terms: D000293:Adolescent; D001317:Austria / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000517:prevention & control; D015331:Cohort Studies; D003967:Diarrhea / Q000453:epidemiology / Q000821:virology; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D005511:Food Handling; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D063373:Hand Hygiene; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D029322:Norovirus / Q000302:isolation & purification*; D012574:Schools; D011795:Surveys and Questionnaires
keywords: Asymptomatic infection; Cohort study; Disease outbreak; Food preparation; Molecular epidemiology; Norovirus