title: [Norovirus gastroenteritis outbreak by person-to-person transmission in a nursing home].
abstract: OBJECTIVE
  The aim of this study was to conduct an investigation into an outbreak of gastroenteritis among health workers and residents (with different grades of dependence) at a nursing home.
  
  
  METHODS
  We detected an outbreak of gastroenteritis in a group of 52 health workers and 124 residents at a nursing home in Oliana, Lleida (Spain). A bidirectional prospective and retrospective cohort study was conducted into the consumption of water, food, grade of dependence (high, medium and low), and specific job. We studied the water supply and six food items. Faecal specimens from 30 patients were cultured and examined for Norovirus by polymerase chain reaction-reverse transcription. The possible implication of different factors associated with gastroenteritis was assessed by relative risk (RR) at 95% confidence intervals (CI).
  
  
  RESULTS
  We interviewed 97% of the patients (172/176). The overall attack rate was 53.3% (92/172). The symptoms were: diarrhoea 68.5% (63/92), vomiting 64.1% (59/92), nausea 63.0% (58/92), fever 33.7% (31/92), abdominal pain 28.3% (26/92), and headache 14.1% (13/92). The epidemic curve highlighted transmission for 19 days. The risk factors associated with gastroenteritis were high (RR = 1.6; 95% CI, 1.0-2.6) and medium (RR = 2.8; 95% CI, 1.0-8.0) levels of dependence, health worker with high level of contact with residents (RR = 2.8; 95% CI, 1.1-7.3) and those doing cleaning work (RR = 2.8; 95% CI, 1.0-8.0). Bacterial cultures were negative for samples of food and water. Also, cultures were negative for bacteria in faecal samples but tests were positive for Norovirus in 12 faecal samples.
  
  
  CONCLUSIONS
  We showed a Norovirus outbreak in a nursing home, person-to-person spread, associated to high and medium grades of dependence among residents, health worker with high level of contact with them and with those doing cleaning work.
authors.affiliation: Delegacion Territorial de Lleida, Departamento de Salud, Generalitat de Catalunya, 25199 Lleida, Spain. pere.godoy@gencat.net
authors.forename: Pere
authors.initials: P
authors.lastname: Godoy
authors.forename: Antoni
authors.initials: A
authors.lastname: Artigues
authors.forename: Rosa
authors.initials: R
authors.lastname: Bartolomé
authors.forename: Angela
authors.initials: A
authors.lastname: Dominguez
authors.forename: Antoni
authors.initials: A
authors.lastname: Plasència
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000635:transmission*; D003428:Cross Infection; D004196:Disease Outbreaks; D018562:Disease Transmission, Infectious; D016021:Epidemiologic Studies; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029322:Norovirus / Q000302:isolation & purification*; D009735:Nursing Homes; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology