Emergence of Dengue virus 4 genotypes II b and I in the city of Rio de Janeiro

CAMPOS R.DE M.; VEIGA, C.S.B.; MENESES, M.D.F.; DE SOUZA, L.M.; MALIRAT, V.; ALBUQUERQUE, J.P.; SCHMIDT-CHANASIT, J.; FERREIRA, D.F.

JOURNAL OF CLINICAL VIROLOGY : THE OFFICIAL PUBLICATION OF THE PAN AMERICAN SOCIETY FOR CLINICAL VIROLOGY.

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 56 p. 86 - 88

1386-6532

Dengue virus (DENV) is an arthropod-borne virus (arbovirus) within the family Flaviviridae and consists of four serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). DENV is able to infect humans and cause dengue fever (DF) or dengue hemorrhagic fever (DHF). In Brazil, outbreaks of DF caused by DENV-1 occurred since the early 80s of the last century and the number of DHF cases increased after 1994, as a result of the introduction of DENV-2 and DENV-3 and the spread of the main vector Aedes aegypti. DENV-4 was first detected in 1982 in the Amazon region of Brazil, co-circulating with DENV-1. However, DF or DHF caused by DENV-4 were not observed in Brazil until 2008, when three patients in the Amazon region suffered from DF caused by DENV-4 genotype 1. During an outbreak of DENV-1 in the city of Niteroi (state of Rio de Janeiro) in March 2011, DENV-4 was detected in 7 patients. The emergence of DENV-4 in the state of Rio de Janeiro in March 2011 forced us to im plement a powerful DENV surveillance program in the city of Rio de Janeiro that led to the fast and reliable identification of DENV-4 infections in December 2011. Phylogenetic analysis, based on 322 nucleotides spanning partial sequences of C and PrM genes of these isolates revealed the predominant presence of genotype 2b (nine samples) and one isolate belonging to genotype 1, during the outbreak in the city of Rio de Janeiro. The nine genotype 2 b isolates were closely related to strains detected in the city of Roraima in 2008 and in the state of São Paulo in 2011.  DENV-4 genotype 2 strains have been also found in other countries of South America. Our strains are more closely related to those strains from Venezuela and Colombia. Interestingly, the only  DENV-4 genotype 1 isolate found in our study is closely related to strains previously isolated in the city of Manaus, Brazil, in the year 2008. The characterization of the circulating DENV-4 genotypes might help to improve our understanding of how DENV-4 spread in the region, how it was introduced into the continent, its maintenance in the environment and if there might be an association between a specific DENV-4 genotype and the severity of DF or DHF. In addition, studies to perform an active mosquito-based surveillance for DENV and other arboviruses are in progress in the city of Rio de Janeiro. This might provide data about arbovirus activity and distribution before an outbreak occurs.