Emerging Infectious Diseases (Aug 2013)

Effects and Clinical Significance of GII.4 Sydney Norovirus, United States, 2012–2013

  • Eyal Leshem,
  • Mary Wikswo,
  • Leslie Barclay,
  • Eric Brandt,
  • William Storm,
  • Ellen Salehi,
  • Traci DeSalvo,
  • Tim Davis,
  • Amy Saupe,
  • Ginette Dobbins,
  • Hillary A. Booth,
  • Christianne Biggs,
  • Katie Garman,
  • Amy M. Woron,
  • Umesh D. Parashar,
  • Jan Vinjé,
  • Aron J. Hall

DOI
https://doi.org/10.3201/eid1908.130458
Journal volume & issue
Vol. 19, no. 8
pp. 1231 – 1238

Abstract

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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.

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