Molecular surveillance of dengue virus in Bahia State, Brazil

Abstract

Dengue is an important emerging viruses, posing a threat to one-third of the global human population. In 2002, the introduction of DENV-3 in the state of Ba-hia produced massive epidemic (about 35,000 cases detected) and the first cases of dengue hemorrhagic fever. To understand the nature of the virus circulat-ing at Bahia, E/NS1 sequence was determined for 31 DENV viruses isolated in Bahia during the 2006 and 2007 transmission season, from patients presenting with different degrees of severity. The carboxi-ter-minal region of the E gene (220 nt) of 31 viruses, iso-lated from dengue patients with clinical diagnosis of dengue infection were used to determine the genetic variability of dengue 2 (DENV-2) and dengue 3 (DENV-3). Sequence data were used in phylogenetic compari-sons with global samples of DENV-2 and DENV-3. DENV-2 sample grouped in the South East Indian genotype, while DENV-3 samples were grouped within Indian genotype. This study is the first report on Ba-hia isolates during two transmission seasons. Our da-ta confirms reports from other parts of Brazil and di-fferent countries showing the DENV-3 (genotype III) strains circulating in the Americas are closely related, and cluster within the genotype that has been associ-ated with DHF epidemics in different continents.