title: Molecular epidemiology of norovirus GII.4 variants in children under 5 years with sporadic acute gastroenteritis in South Korea during 2006-2013.
abstract: BACKGROUND
  The global emergence of norovirus (NoV) GII.4 variants has raised public concerns in the world including South Korea since 1996.
  
  
  OBJECTIVE
  We analyzed seasonality and genotypic pattern for sporadic cases by norovirus GII-4 variants.
  
  
  METHODS
  To determine the epidemic status of GII.4 variants in South Korea during 2006-2013, 7301 fecal specimens were collected from children who were younger than 5 years and had sporadic acute gastroenteritis (AGE).
  
  
  RESULTS
  During the study period, NoVs were the most prevalent viral agent, detected in 877 (12.0%) of the 7301 fecal specimens from children with sporadic AGE. NoV GII strains predominantly accounted for 97.6% of all sporadic NoV infections. NoV GII.4 was the most prevalent genotype and comprised 67.6% of the NoV GII strains. However, seasonal prevalence of GII.4 strains varied depending on the spread of GII.4 variants. GII.4-2006b variant most predominantly circulated from 2006-2007 to 2009-2010 and persisted during other seasons. GII.4-2009 variant was first detected in January 2010 and predominant in 2011-2012. However, it was rapidly displaced by GII.4-2012 variant, which emerged in May 2012 and substantially circulated in 2012-2013.
  
  
  CONCLUSIONS
  The frequent emergence and rapid spread of GII.4 variants significantly affect the magnitude of sporadic NoV infections in children. Hence, to minimize the disease burden of NoV infections, GII.4 strains should be considered as a primary target for vaccine development against NoVs.
authors.affiliation: Division of Virology, Gyeonggi Provincial Research Institute of Public Health and Environment, Suwon, Republic of Korea; Department of Life Science, The University of Seoul, Seoul, Republic of Korea.
authors.forename: Han-Gil
authors.initials: HG
authors.lastname: Cho
authors.affiliation: Korea Zoonosis Research Institute, Chonbuk National University, Iksan, Republic of Korea.
authors.forename: Sung-Geun
authors.initials: SG
authors.lastname: Lee
authors.affiliation: Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Ju-Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Division of Virology, Gyeonggi Provincial Research Institute of Public Health and Environment, Suwon, Republic of Korea.
authors.forename: Kyeong-Sin
authors.initials: KS
authors.lastname: Yu
authors.affiliation: Division of Enteric Disease, Center for Infectious Disease, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, Republic of Korea.
authors.forename: Deog-Yong
authors.initials: DY
authors.lastname: Lee
authors.affiliation: Division of Virology, Gyeonggi Provincial Research Institute of Public Health and Environment, Suwon, Republic of Korea.
authors.forename: Po-Hyun
authors.initials: PH
authors.lastname: Park
authors.affiliation: Division of Virology, Gyeonggi Provincial Research Institute of Public Health and Environment, Suwon, Republic of Korea.
authors.forename: Mi-Hye
authors.initials: MH
authors.lastname: Yoon
authors.affiliation: Department of Life Science, The University of Seoul, Seoul, Republic of Korea.
authors.forename: Eek-Hoon
authors.initials: EH
authors.lastname: Jho
authors.affiliation: Department of Biochemistry, School of Medicine, Gachon University, Incheon, Republic of Korea. Electronic address: geretics@gachon.ac.kr.
authors.forename: Jaehong
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea. Electronic address: paik@catholic.ac.kr.
authors.forename: Soon-Young
authors.initials: SY
authors.lastname: Paik
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D002675:Child, Preschool; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D017720:Molecular Epidemiology; D029322:Norovirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012621:Seasons
keywords: GII.4 variant; Genogroup; Norovirus; Viral gastroenteritis