Norovirus illness is a global problem: emergence and spread of norovirus GII.4 variants, 2001-2007.
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.
Siebenga
J Joukje
JJ
National Institute for Public Health and the Environment, Bilthoven, the Netherlands. Joukje.Siebenga@RIVM.nl
Vennema
Harry
H
Zheng
Du-Ping
DP
Vinjé
Jan
J
Lee
Bonita E
BE
Pang
Xiao-Li
XL
Ho
Eric C M
EC
Lim
Wilina
W
Choudekar
Avinash
A
Broor
Shobha
S
Halperin
Tamar
T
Rasool
Nassar B G
NB
Hewitt
Joanne
J
Greening
Gail E
GE
Jin
Miao
M
Duan
Zhao-Jun
ZJ
Lucero
Yalda
Y
O'Ryan
Miguel
M
Hoehne
Marina
M
Schreier
Eckart
E
Ratcliff
Rodney M
RM
White
Peter A
PA
Iritani
Nobuhiro
N
Reuter
Gábor
G
Koopmans
Marion
M
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
D012367:RNA, Viral