title: Noroviruses associated with outbreaks of acute gastroenteritis in the State of Rio Grande do Sul, Brazil, 2004-2011.
abstract: BACKGROUND
  Acute gastroenteritis norovirus (NoV) in a country of continental dimensions like Brazil has resulted in under-reporting of the number of outbreaks, as well as the genotypes associated.
  
  
  OBJECTIVE
  To demonstrate the role of NoV in outbreaks occurring in the State of Rio Grande do Sul, Southern Brazil, we determined its prevalence, as well as the genotypes associated, and evaluated clinical and epidemiological aspects.
  
  
  METHODS
  NoV investigation was carried out in rotavirus group A negative stool samples from 2265 patients from 741 outbreaks that occurred in the State of Rio Grande do Sul, Brazil, during a period of eight years (2004-2011). NoV detection and nucleotide sequencing for genotype characterization was carried by using sets of primers targeting a conservative Rd-Rp polymerase genome region and the viral capsid gene, respectively.
  
  
  RESULTS
  NoVs were detected in 817 stool samples (36.1%) and associated with 327 outbreaks (44.1%). NoV GII.2, GII.3, GII.4, GII.6, GII.12, GII.13, GII.14, GII.15, GII.17, GII.21; and GI.1 and GI.3 were characterized. GII.4 was the most frequently detected (72.3%), with five variants identified (Asia_2003, Hunter_2004, Yerseke_2006a, Den_Haag_2006b, New Orleans_2009). This study describes the first detection of GI.1 and GII.13 and GII.15 in Brazil and demonstrates NoV winter-spring seasonality in this region of the country.
  
  
  CONCLUSIONS
  NoVs were responsible for almost 50% of outbreaks, with about 70% of them resulting from genotype GII.4 and its variants. The seasonality observed could help health authorities to establish a system of active surveillance in order to reduce NoV impact especially in congregate settings.
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil. Electronic address: juliana@ioc.fiocruz.br.
authors.forename: Juliana da Silva Ribeiro
authors.initials: Jda S
authors.lastname: de Andrade
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Monica Simões
authors.initials: MS
authors.lastname: Rocha
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Felipe Aníbal
authors.initials: FA
authors.lastname: Carvalho-Costa
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Julia Monassa
authors.initials: JM
authors.lastname: Fioretti
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Maria da Penha Trindade Pinheiro
authors.initials: Mda P
authors.lastname: Xavier
authors.affiliation: Central Laboratory of State of Rio Grande do Sul, State Foundation of Production and Health Research, Porto Alegre, RS, Brazil.
authors.forename: Zenaida Maria Alves
authors.initials: ZM
authors.lastname: Nunes
authors.affiliation: Department of Epidemiologic Surveillance, State Department of Health, Porto Alegre, RS, Brazil.
authors.forename: Jeanice
authors.initials: J
authors.lastname: Cardoso
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Alexandre Madi
authors.initials: AM
authors.lastname: Fialho
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: José Paulo Gagliardi
authors.initials: JP
authors.lastname: Leite
authors.affiliation: Laboratory of Comparative and Environmental Virology - Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Ministry of Health, Rio de Janeiro, RJ, Brazil.
authors.forename: Marize Pereira
authors.initials: MP
authors.lastname: Miagostovich
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics; D012621:Seasons; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014764:Viral Proteins / Q000235:genetics; D055815:Young Adult
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins
keywords: Acute gastroenteritis outbreaks; GII variants; Genotypes; Noroviruses; Southern Brazil