Caracterização molecular e análise filogenética dos vírus dengue circulantes na cidade de Boa Vista, Roraima , Brasil

Abstract

Dengue virus (DENV) are the etiologic agent of the most important arbovirosis from Tropical and Subtropical region. They are classified as flaviviruses following their genetic and antigenic properties into four groups: DENV1, DENV2, DENV3 and DENV4. In the last decades, dengue fever has increased its virulence and several factors had been associated to this increasing. Secondary infection and viral factors are the main one implicated to increase of severe form of dengue fever. In this study, were analysed 80 samples of serum from patients with suspect of dengue infection from Boa Vista. We aim to identify the DENV serotypes and genotypes circulating in this city. Eighty samples were inoculated in C6/36 cells. The RNAs were extracted and viral identity was archieved using by Reverse Transcription – Polymerase Chain Reaction (RT-PCR) method developed by Lanciotti et al. (1992). After viral type identification, cDNA was used to PCR with specific primers to gene E. The sequencing was performed on MEGABACE1000 platform. Maximum Likelihood dendrograms were constructed by PhyML 3.0. Branch confidences were calculated using approximated Likelihood Ratio Test (aLRT). Thirty four samples were isolated and identified: 23 DENV1 strains and 11 DENV2 strains, three of them were coinfection. After edition of sequences, 15 fragments with 962nt large of DENV1 and three fragments with 825nt large of DENV2 were used to analysis. DENV1 strains isolated in this study grouped with strains of genotype V, together with strains from Venezuela and Brazil, previously described. DENV2 strains were classified as american/asian genotype, together to Cuba and Taiwan strains. Data obtained shown strong relantionship between Roraima strains and Venezuelan and Caribbean strains. The results help future analysis about DENV evolution and gene flow in Brasil and its relationship with DENV isolated in other regions of American Continent.