title: Rapid detection of a norovirus pseudo-outbreak by using real-time sequence based information.
abstract: BACKGROUND
  Sequence based information is increasingly used to study the epidemiology of viruses, not only to provide insight in viral evolution, but also to understand transmission patterns during outbreaks. However, sequence analysis is not yet routinely performed by diagnostic laboratories, limiting its use in clinical practice.
  
  
  OBJECTIVE
  To describe the added value of sequence based information available within 3 days after the detection of norovirus in fecal samples of patients and personnel during a suspected outbreak on a hospital ward. Results were used to guide the implementation of appropriate infection control measures, in particular closure of the ward.
  
  
  METHODS
  Observational study.
  
  
  RESULTS
  Norovirus infection was detected in seven patients and two health care workers on an oncology ward of the children's hospital. Six of seven patients had a hospital acquired infection defined as a first day of illness more than two days after admission. After notification of the first two patients, supplementary infection control measures were taken to prevent further spread. Despite these measures, three additional patients with norovirus infection were identified. Characterization of the noroviruses of 5 out of 7 patients was available within 7 days after the notification of the first patient. Four different genotypes were detected, providing evidence for multiple introductions of different norovirus strains with only a few secondary cases rather than ongoing nosocomial transmission. Therefore, we maintained the already implemented infection control interventions without closure of the ward.
  
  
  CONCLUSIONS
  Sequence based information available in real-time is helpful for understanding norovirus transmission in the hospital and facilitates appropriate infection control measures during an outbreak.
authors.affiliation: Department of Medical Microbiology, Division of Clinical Virology, University of Groningen, University Medical Center Groningen, The Netherlands. j.c.rahamat@umcg.nl
authors.forename: J C
authors.initials: JC
authors.lastname: Rahamat-Langendoen
authors.forename: M
authors.initials: M
authors.lastname: Lokate
authors.forename: E H
authors.initials: EH
authors.lastname: Schölvinck
authors.forename: A W
authors.initials: AW
authors.lastname: Friedrich
authors.forename: H G M
authors.initials: HG
authors.lastname: Niesters
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology* / Q000821:virology; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D017053:Infection Control; D017720:Molecular Epidemiology; D029322:Norovirus / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D012367:RNA, Viral
keywords: Norovirus; Nosocomial infection; Sequence analysis; Transmission