Caracterização molecular e análise filogenética de Dengue virus 1 isolado em Alfenas, Minas Gerais

Abstract

Dengue virus is an arbovirus transmitted to humans through the bite of infected female Aedes aegypti mosquitoes. The disease is endemic in 112 countries in Africa, Americas, Mediterranean, South East Asia and Western Pacific. The World Health Organization estimates that 40% of the world population lives in areas at risk for dengue. Molecular characterization helps to understand and monitor the genetic diversity of DENV, as well as the variability in virulence of circulating viral isolated. The four serotypes of DENV circulate in Minas Gerais state, however few studies have been conducted about the population dynamics of DENV in this state. The isolate BR/Alfenas/2012 analyzed in this study was obtained from the serum sample from a patient with dengue hemorrhagic fever. The coding region of the E and NS5 protein were amplified by RT-PCR and used in phylogenetic studies. The analysis grouped this isolate in genotype V, line L1, getting very close to isolates from Rio de Janeiro, Brazil's North and other isolated from Venezuela and Colombia. The phylogeographic analysis provided evidence that the isolated BR/Alfenas/2012 is a direct descendant of samples from Rio de Janeiro in 2010 and 2011, and the common ancestor isolated DENV-1/VE/BID-V2468/2008, from Venezuela. Analysis of the coding region of the E protein showed that the isolated BR/Alfenas/2012 differ from 14 to other isolates from the same genotype and lineage, thereby generating mutations synonymous and non-synonymous. To characterize the virulent potential of this isolate, Swiss mice were infected with 1 x 104 plaque forming units. Seven days after infection, the animals were sacrified and the liver removed for histopathological analysis. The liver of infected animals showed a presence of inflammatory cells, steatosis and also focal points of edhema, hemorrhage and necrosis. This is the first report of the isolation of DENV-1, in the south of Minas Gerais, which allowed starting an inference about the distribution and genetic diversity of the virus.