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Open Access Short report

First report of multiple lineages of dengue viruses type 1 in Rio de Janeiro, Brazil

Flavia B dos Santos1*, Fernanda B Nogueira1, Márcia G Castro2, Priscila CG Nunes1, Ana Maria B de Filippis1, Nieli RC Faria1, Jaqueline BS Simões1, Simone A Sampaio1, Clarice R Santos1 and Rita Maria R Nogueira1

Author Affiliations

1 Laboratório de Flavivirus, Oswaldo Cruz Institute, Rio de Janeiro, Brazil

2 Laboratório de Transmissores de Hematozoários, Oswaldo Cruz Institute, Rio de Janeiro, Brazil

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Virology Journal 2011, 8:387  doi:10.1186/1743-422X-8-387

Published: 3 August 2011

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.

Findings

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.

Keywords:
Dengue virus type 1; multiple lineages; phylogeny; Rio de Janeiro