title: Respiratory syncytial virus epidemic periods in an equatorial city of Brazil.
abstract: BACKGROUND
  Characterization of the human respiratory syncytial virus (HRSV) season at the local level has important implications for appropriate decisions on the time period for administration of specific prophylaxis.
  
  
  OBJECTIVE
  (1) To describe five consecutive epidemic periods of HRSV in an equatorial city of Brazil and (2) to show preliminary data on genomic diversity of circulating HRSV.
  
  
  METHODS
  Nasopharyngeal aspirates of 2885 children attending the emergency room and wards of a public hospital were collected and screened by indirect immunofluorescence for HRSV infections during five consecutive years (from January 2004 to December 2008). In addition, the genetic and antigenic variability of the HRSV strains isolated was evaluated by partial nucleotide sequencing of the protein G gene.
  
  
  RESULTS
  HRSV was detected in 15·8% of the analyzed samples. HRSV seasons occurred in a restricted period of each year. The onset of each HRSV season was variable (February to May), but the end always occurred in July. From the 456 HRSV infections found, 86 cases with bronchiolitis were genotyped. Both HRSV subgroups (A and B) cocirculated during the five epidemic periods. The 58 HRSV-A strains grouped into two clades, GA2 and GA5. In respect of the HRSV-B strains, the 28 samples grouped into two clades: GB3 and BA.
  
  
  CONCLUSIONS
  HRSV accounts for a substantial proportion of ARI in the study population. As in temperate countries, HRSV infections in this equatorial area of Brazil also cause seasonal yearly epidemics, and this has implications for prophylaxis strategies. The city of Fortaleza follows the same worldwide trend of circulation of genotypes of HRSV.
authors.affiliation: Federal University of Ceara, Fortaleza, Brazil.
authors.forename: Fernanda E A
authors.initials: FE
authors.lastname: Moura
authors.forename: Anne C B
authors.initials: AC
authors.lastname: Perdigão
authors.forename: Joyce F
authors.initials: JF
authors.lastname: Ribeiro
authors.forename: Caroline M G D
authors.initials: CM
authors.lastname: Florêncio
authors.forename: Francisco M S
authors.initials: FM
authors.lastname: Oliveira
authors.forename: Samuel A R
authors.initials: SA
authors.lastname: Pereira
authors.forename: Viviane F
authors.initials: VF
authors.lastname: Botosso
authors.forename: Marilda M
authors.initials: MM
authors.lastname: Siqueira
authors.forename: Luciano M
authors.initials: LM
authors.lastname: Thomazelli
authors.forename: Raquel N
authors.initials: RN
authors.lastname: Caldeira
authors.forename: Danielle B L
authors.initials: DB
authors.lastname: Oliveira
authors.forename: Edison L
authors.initials: EL
authors.lastname: Durigon
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D058872:Epidemics; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology*; D018113:Respiratory Syncytial Virus, Human / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012621:Seasons; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; C116204:attachment protein G
keywords: Antigenic groups and genomic diversity; human respiratory syncytial virus