title: Outbreak of acute norovirus gastroenteritis in a military facility in Singapore: a public health perspective.
abstract: BACKGROUND
  Norovirus gastrointestinal disease (GID) outbreaks occur frequently in closed settings, with high attack rates. On October 16, 2008, a norovirus GID outbreak occurred at a Singapore military camp. This study describes the epidemiological investigations conducted to determine the cause of outbreak and the efficacy of the public health measures implemented.
  
  
  METHODS
  Epidemiologic investigations included a case-control study of exposure to different food items and an environmental exposure survey. Stool samplings of patients and food handlers for common pathogens, and microbiologic testing of food and water samples were performed. Inspection of dining facilities and health screening of all food-handlers were also conducted.
  
  
  RESULTS
  A total of 156 GID cases were reported on October 15-31, 2008. 24 (15.4%) personnel were positive for norovirus. The predominant symptoms were diarrhoea (76.3%) and abdominal pain (69.2%). There was no clinical correlation between any food item and the affected personnel. Testing of food and water samples, dining facility inspections and health screening of food handlers showed satisfactory results. The environmental exposure survey indicated possible transmission due to environmental contamination by vomitus in common areas. Comprehensive environmental decontamination was performed with hypochlorite solution, and personal hygiene measures were enforced. The outbreak lasted 17 days, with a decline in cases post intervention.
  
  
  CONCLUSIONS
  Timely notification and prompt response can curtail disease transmission. Swift implementation of public health measures, such as emphasis on personal hygiene, isolation of affected cases and comprehensive disinfection of the environment, effectively stopped norovirus transmission and may be adapted for future GID outbreaks.
authors.affiliation: Biodefence Centre, Ministry of Defence, Singapore.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Yap
authors.forename: Abdul
authors.initials: A
authors.lastname: Qadir
authors.forename: Isaac
authors.initials: I
authors.lastname: Liu
authors.forename: Jimmy
authors.initials: J
authors.lastname: Loh
authors.forename: Boon Huan
authors.initials: BH
authors.lastname: Tan
authors.forename: Vernon J
authors.initials: VJ
authors.lastname: Lee
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D017250:Caliciviridae Infections / Q000175:diagnosis / Q000453:epidemiology*; D016022:Case-Control Studies; D003140:Communicable Disease Control / Q000379:methods; D003967:Diarrhea / Q000821:virology*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005243:Feces / Q000821:virology; D005511:Food Handling; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology*; D006801:Humans; D008297:Male; D058749:Military Facilities; D029322:Norovirus / Q000302:isolation & purification*; D012846:Singapore / Q000453:epidemiology; D014871:Water Microbiology; D055815:Young Adult