title: Genotypes, recombinant forms, and variants of norovirus GII.4 in Gipuzkoa (Basque Country, Spain), 2009-2012.
abstract: BACKGROUND
  Noroviruses (NoVs) are genetically diverse, with genogroup II-and within it-genotype 4 (GII.4) being the most prevalent cause of acute gastroenteritis worldwide. The aim of this study was to characterize genogroup II NoV causing acute gastroenteritis in the Basque Country (northern Spain) from 2009-2012.
  
  
  METHODS
  The presence of NoV RNA was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) in stool specimens from children younger than 15 years old with community-acquired acute gastroenteritis, and from hospitalized adults or elderly residents of nursing homes with acute gastroenteritis. For genotyping, the open reading frames ORF1 (encoding the polymerase) and ORF2 (encoding the major capsid protein) were partially amplified and sequenced. Recombinant strains were confirmed by PCR of the ORF1/ORF2 junction region.
  
  
  RESULTS
  NoV was detected in 16.0% (453/2826) of acute gastroenteritis episodes in children younger than 2 years, 9.9% (139/1407) in children from 2 to 14 years, and 35.8% (122/341) in adults. Of 317 NoVs characterized, 313 were genogroup II and four were genogroup I. The GII.4 variants Den Haag-2006b and New Orleans-2009 predominated in 2009 and 2010-2011, respectively. In 2012, the New Orleans-2009 variant was partially replaced by the Sydney-2012 variant (GII.Pe/GII.4) and New Orleans-2009/Sydney-2012 recombinant strains. The predominant capsid genotype in all age groups was GII.4, which was the only genotype detected in outbreaks. The second most frequent genotype was GII.3 (including the recently described recombination GII.P16/GII.3), which was detected almost exclusively in children.
  
  
  CONCLUSIONS
  Nine different genotypes of NoV genogroup II were detected; among these, intergenotype recombinant strains represented an important part, highlighting the role of recombination in the evolution of NoVs. Detection of new NoV strains, not only GII.4 strains, shortly after their first detection in other parts of the world shows that many NoV strains can spread rapidly.
authors.affiliation: Servicio de Microbiología, Hospital Universitario Donostia-Instituto de Investigación Biodonostia, San Sebastián, Spain.
authors.forename: Ainara
authors.initials: A
authors.lastname: Arana
authors.affiliation: Servicio de Microbiología, Hospital Universitario Donostia-Instituto de Investigación Biodonostia, San Sebastián, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), San Sebastián, Spain.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Cilla
authors.affiliation: Servicio de Microbiología, Hospital Universitario Donostia-Instituto de Investigación Biodonostia, San Sebastián, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), San Sebastián, Spain.
authors.forename: Milagrosa
authors.initials: M
authors.lastname: Montes
authors.affiliation: Servicio de Microbiología, Hospital Universitario Donostia-Instituto de Investigación Biodonostia, San Sebastián, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Gomariz
authors.affiliation: Servicio de Microbiología, Hospital Universitario Donostia-Instituto de Investigación Biodonostia, San Sebastián, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), San Sebastián, Spain; Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad del País Vasco (UPV/EHU), San Sebastián, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Pérez-Trallero
mesh_terms: D000293:Adolescent; D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000266:history / Q000821:virology*; D036022:Capsid Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D049674:History, 21st Century; D006801:Humans; D007223:Infant; D008297:Male; D029322:Norovirus / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D016865:Reassortant Viruses; D012621:Seasons; D013030:Spain / Q000453:epidemiology
chemical_list: D036022:Capsid Proteins