title: First report of multiple lineages of dengue viruses type 1 in Rio de Janeiro, Brazil.
abstract: BACKGROUND
  In Brazil dengue has been a major public health problem since DENV-1 introduction and spread in 1986. After a low or silent co-circulation, DENV-1 re-emerged in 2009 causing a major epidemic in the country in 2010 and 2011. In this study, the phylogeny of DENV-1 strains isolated in RJ after its first introduction in 1986 and after its emergence in 2009 and 2010 was performed in order to document possible evolutionary patterns or introductions in a re-emergent virus.
  
  
  RESULTS
  The analysis of the E gene sequences demonstrated that DENV-1 isolated during 2009/2010 still belong to genotype V (Americas/Africa) but grouping in a distinct clade (lineage II) of that represented by earlier DENV-1 (lineage I). However, strains isolated in 2011 grouped together forming another distinct clade (lineage III).
  
  
  CONCLUSIONS
  The monitoring of DENV is important to observe the spread of potentially virulent strains as well to evaluate its impact over the population during an outbreak. Whether explosive epidemics reported in Brazil caused mainly by DENV-1 was due to lineage replacement, or due the population susceptibility to this serotype which has not circulated for almost a decade or even due to the occurrence of secondary infections in a hyperendemic country, is not clear. This is the first report of multiple lineages of DENV-1 detected in Brazil.
authors.affiliation: Laboratório de Flavivirus, Oswaldo Cruz Institute, Rio de Janeiro, Brazil. flaviab@ioc.fiocruz.br
authors.forename: Flavia B
authors.initials: FB
authors.lastname: dos Santos
authors.forename: Fernanda B
authors.initials: FB
authors.lastname: Nogueira
authors.forename: Márcia G
authors.initials: MG
authors.lastname: Castro
authors.forename: Priscila Cg
authors.initials: PC
authors.lastname: Nunes
authors.forename: Ana Maria B
authors.initials: AM
authors.lastname: de Filippis
authors.forename: Nieli Rc
authors.initials: NR
authors.lastname: Faria
authors.forename: Jaqueline Bs
authors.initials: JB
authors.lastname: Simões
authors.forename: Simone A
authors.initials: SA
authors.lastname: Sampaio
authors.forename: Clarice R
authors.initials: CR
authors.lastname: Santos
authors.forename: Rita Maria R
authors.initials: RM
authors.lastname: Nogueira
mesh_terms: D001938:Brazil / Q000453:epidemiology; D016000:Cluster Analysis; D003715:Dengue / Q000453:epidemiology* / Q000821:virology*; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D019143:Evolution, Molecular; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; C072281:E protein TH Sman, Dengue virus