Characterization of dengue virus serotype 1 in epidemics in Porto Velho, Rondônia, in 2001-2003

ABSTRACT

The first dengue fever epidemic in the State of Rondônia (western region of Brazil) was recorded in 1997, without laboratory confirmation. Following this, there was an epidemic in Manaus, in the neighboring State of Amazon, in 1998, in which DENV-1 and DENV-2 viruses were isolated from patients. In the present paper, the serotype characterization of the dengue virus isolated from patients with clinically suspected dengue in Porto Velho, Rondônia, between 2001 and 2003 is described. One hundred and fifty blood samples were collected between the first and fifth days of symptoms. Seventy samples of virus isolates were subjected to dengue identification by means of RT-PCR using universal primers for the NS1 gene of DENV, which amplifies a 419 bp fragment. The amplicons obtained were subjected to enzymatic digestion to characterize the viral serotypes. All the samples analyzed were DENV-1. A nucleotide sequence randomly selected from one amplicon, which was also DENV-1, presented 98 percent similarity to sequences from Southeast Asia that were obtained from GenBank.

RESUMO

A primeira epidemia de febre do dengue no Estado de Rondônia, Região Ocidental do Brasil foi registrado em 1997, sem confirmação laboratorial. Em seguida, houve uma epidemia descrita em 1998, em Manaus, no vizinho Estado do Amazonas, onde os vírus DENV-1 e DENV-2 foram isolados de pacientes. No presente artigo, foi descrito a caracterização do sorotipo do vírus dengue isolado de pacientes com suspeitas clinicas de dengue em Porto Velho, Rondônia, entre 2001 a 2003. Foram coletadas 150 amostras de sangue, entre primeiro e quinto dia de sintomas. Setenta amostras de vírus isolados foram submetidas a identificação do dengue pela RT-PCR usando primers universais para gene da NS1 do DENV que amplifica um fragmento de 419pb. O amplicon obtidos foram submetidos a digestão enzimática para caracterização do sorotipo viral. Todas as amostras analisadas foram DENV-1. A seqüência nucleotídica de um dos amplicons aleatoriamente selecionada também DENV-1 demonstrou 98 por cento similaridade com as seqüências do Sudeste Asiático obtidas no GenBank.