Epidemics of gastroenteritis during 2006 were associated with the spread of norovirus GII.4 variants 2006a and 2006b.
BACKGROUND
Acute gastroenteritis is commonly associated with norovirus genogroup II (GII) infection. Norovirus GII has 17 classified genotypes (GII.1-GII.17), but only 1 norovirus genotype (GII.4) is associated with global epidemics of gastroenteritis. In 2006, an increase in global norovirus activity was observed.


METHODS
During the period from December 2005 through August 2006, a total of 231 fecal samples were obtained from patients with acute gastroenteritis from Australia and New Zealand. Norovirus RNA was amplified and sequenced to determine norovirus genotype and relatedness to known epidemic norovirus GII.4 variants.


RESULTS
Two GII.4 variants, designated 2006a and 2006b, were identified in 61.8% and 11.3%, respectively, of the 186 cases investigated. Norovirus 2006a and 2006b have also been implicated as the predominant causes of norovirus-associated gastroenteritis across Europe in 2006.


CONCLUSIONS
The global increase in norovirus-associated gastroenteritis in 2006 was linked to the emergence of 2 novel GII.4 variants, 2006a and 2006b.
Tu
Elise T-V
ET
School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia.
Bull
Rowena A
RA
Greening
Gail E
GE
Hewitt
Joanne
J
Lyon
Michael J
MJ
Marshall
John A
JA
McIver
Christopher J
CJ
Rawlinson
William D
WD
White
Peter A
PA
D001315:Australia / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D005838:Genotype; D006801:Humans; D009520:New Zealand / Q000453:epidemiology; D029322:Norovirus / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny