title: Effects and clinical significance of GII.4 Sydney norovirus, United States, 2012-2013.
abstract: During 2012, global detection of a new norovirus (NoV) strain, GII.4 Sydney, raised concerns about its potential effect in the United States. We analyzed data from NoV outbreaks in 5 states and emergency department visits for gastrointestinal illness in 1 state during the 2012-13 season and compared the data with those of previous seasons. During August 2012-April 2013, a total of 637 NoV outbreaks were reported compared with 536 and 432 in 2011-2012 and 2010-2011 during the same period. The proportion of outbreaks attributed to GII.4 Sydney increased from 8% in September 2012 to 82% in March 2013. The increase in emergency department visits for gastrointestinal illness during the 2012-13 season was similar to that of previous seasons. GII.4 Sydney has become the predominant US NoV outbreak strain during the 2012-13 season, but its emergence did not cause outbreak activity to substantially increase from that of previous seasons.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. eleshem@cdc.gov
authors.forename: Eyal
authors.initials: E
authors.lastname: Leshem
authors.forename: Mary
authors.initials: M
authors.lastname: Wikswo
authors.forename: Leslie
authors.initials: L
authors.lastname: Barclay
authors.forename: Eric
authors.initials: E
authors.lastname: Brandt
authors.forename: William
authors.initials: W
authors.lastname: Storm
authors.forename: Ellen
authors.initials: E
authors.lastname: Salehi
authors.forename: Traci
authors.initials: T
authors.lastname: DeSalvo
authors.forename: Tim
authors.initials: T
authors.lastname: Davis
authors.forename: Amy
authors.initials: A
authors.lastname: Saupe
authors.forename: Ginette
authors.initials: G
authors.lastname: Dobbins
authors.forename: Hillary A
authors.initials: HA
authors.lastname: Booth
authors.forename: Christianne
authors.initials: C
authors.lastname: Biggs
authors.forename: Katie
authors.initials: K
authors.lastname: Garman
authors.forename: Amy M
authors.initials: AM
authors.lastname: Woron
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
authors.forename: Jan
authors.initials: J
authors.lastname: Vinjé
authors.forename: Aron J
authors.initials: AJ
authors.lastname: Hall
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D004196:Disease Outbreaks; D004636:Emergency Service, Hospital; D062665:Epidemiological Monitoring; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D029322:Norovirus / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014481:United States / Q000453:epidemiology
keywords: GII.4 Sydney strain; United States; enteric infections; norovirus; outbreak; surveillance; viruses