title: Norovirus illness is a global problem: emergence and spread of norovirus GII.4 variants, 2001-2007.
abstract: BACKGROUND
  Noroviruses (NoVs) are the most common cause of viral gastroenteritis. Their high incidence and importance in health care facilities result in a great impact on public health. Studies from around the world describing increasing prevalence have been difficult to compare because of differing nomenclatures for variants of the dominant genotype, GII.4. We studied the global patterns of GII.4 epidemiology in relation to its genetic diversity.
  
  
  METHODS
  Data from NoV outbreaks with dates of onset from January 2001 through March 2007 were collected from 15 institutions on 5 continents. Partial genome sequences (n=775) were collected, allowing phylogenetic comparison of data from different countries.
  
  
  RESULTS
  The 15 institutions reported 3098 GII.4 outbreaks, 62% of all reported NoV outbreaks. Eight GII.4 variants were identified. Four had a global distribution--the 1996, 2002, 2004, and 2006b variants. The 2003Asia and 2006a variants caused epidemics, but they were geographically limited. Finally, the 2001 Japan and 2001 Henry variants were found across the world but at low frequencies.
  
  
  CONCLUSIONS
  NoV epidemics resulted from the global spread of GII.4 strains that evolved under the influence of population immunity. Lineages show notable (and currently unexplained) differences in geographic prevalence. Establishing a global NoV network by which data on strains with the potential to cause pandemics can be rapidly exchanged may lead to improved prevention and intervention strategies.
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands. Joukje.Siebenga@RIVM.nl
authors.forename: J Joukje
authors.initials: JJ
authors.lastname: Siebenga
authors.forename: Harry
authors.initials: H
authors.lastname: Vennema
authors.forename: Du-Ping
authors.initials: DP
authors.lastname: Zheng
authors.forename: Jan
authors.initials: J
authors.lastname: Vinjé
authors.forename: Bonita E
authors.initials: BE
authors.lastname: Lee
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Pang
authors.forename: Eric C M
authors.initials: EC
authors.lastname: Ho
authors.forename: Wilina
authors.initials: W
authors.lastname: Lim
authors.forename: Avinash
authors.initials: A
authors.lastname: Choudekar
authors.forename: Shobha
authors.initials: S
authors.lastname: Broor
authors.forename: Tamar
authors.initials: T
authors.lastname: Halperin
authors.forename: Nassar B G
authors.initials: NB
authors.lastname: Rasool
authors.forename: Joanne
authors.initials: J
authors.lastname: Hewitt
authors.forename: Gail E
authors.initials: GE
authors.lastname: Greening
authors.forename: Miao
authors.initials: M
authors.lastname: Jin
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Duan
authors.forename: Yalda
authors.initials: Y
authors.lastname: Lucero
authors.forename: Miguel
authors.initials: M
authors.lastname: O'Ryan
authors.forename: Marina
authors.initials: M
authors.lastname: Hoehne
authors.forename: Eckart
authors.initials: E
authors.lastname: Schreier
authors.forename: Rodney M
authors.initials: RM
authors.lastname: Ratcliff
authors.forename: Peter A
authors.initials: PA
authors.lastname: White
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Iritani
authors.forename: Gábor
authors.initials: G
authors.lastname: Reuter
authors.forename: Marion
authors.initials: M
authors.lastname: Koopmans
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology*; D016000:Cluster Analysis; D004196:Disease Outbreaks; D019143:Evolution, Molecular; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D006801:Humans; D017720:Molecular Epidemiology; D029322:Norovirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics; D017385:Sequence Homology
chemical_list: D012367:RNA, Viral