title: Molecular epidemiology of norovirus associated with gastroenteritis and emergence of norovirus GII.4 variant 2012 in Japanese pediatric patients.
abstract: In late 2012, an outbreak of acute gastroenteritis due to norovirus variant Sydney_2012 occurred and have been reported from many counties. In this study, we described surveillance study of the incidence of norovirus infections among Japanese pediatric patients in association with gastroenteritis and investigated the antigenic change of the new variant Sydney_2012 circulated in Japanese populations. A total of 2381 fecal specimens collected from children with acute gastroenteritis in Hokkaido, Tokyo, Shizuoka, Kyoto, Osaka, and Saga from 2009 to 2013 were examined for norovirus and further analyzed molecularly. A high proportion (39.3%) of norovirus positive samples and several genotypes were detected. Norovirus GII.4 dominated over other genotypes (71.4%). The Den_Haag_2006b (43.2%) was detected as the predominant variant and co-circulated with New_Orleans_2009 (17.8%) until March 2012. Subsequently, they were displaced by Sydney_2012. The Sydney_2012 variant has been responsible for the majority of norovirus infections in 2012-2013 (85.7%). Although Sydney_2012 variant has a common ancestor with New_Orleans_2009 variant, analysis of P2 sub-domain showed a high level of diversity in comparison with other variants in four amino acid changes at the antigenic sites. The change in particular residue 393 of new variant may affect HBGA recognition. Analysis of noroviruses circulating in the past 4years revealed a change of predominant variant of norovirus GII.4 in each epidemic season. The change of amino acid in putative epitopes may have led the virus escape from the existing herd immunity and explain the increase of new variant outbreaks.
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan.
authors: Aksara
authors: A
authors: Thongprachum
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors: Wisoot
authors: W
authors: Chan-it
authors: Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors: Pattara
authors: P
authors: Khamrin
authors: Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.
authors: Patchreenart
authors: P
authors: Saparpakorn
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan.
authors: Shoko
authors: S
authors: Okitsu
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors: Sayaka
authors: S
authors: Takanashi
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors: Masashi
authors: M
authors: Mizuguchi
authors: Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan.
authors: Satoshi
authors: S
authors: Hayakawa
authors: Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors: Niwat
authors: N
authors: Maneekarn
authors: Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan. Electronic address: ushijima-hiroshi@jcom.home.ne.jp.
authors: Hiroshi
authors: H
authors: Ushijima
mesh_terms: D000293:Adolescent; D001665:Binding Sites; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral; D019143:Evolution, Molecular; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral
keywords: Epidemiology; Gastroenteritis; Japanese; Norovirus; Variant