Caracterização molecular e epidemiológica dos vírus Dengue no estado do Amazonas, Brasil.

Abstract

Dengue virus infection increased significantly in Brazil during the last decade, particularly after 1994, as a consequence of Aedes aegypti dissemination. Vector dispersion was followed by the introduction of DEN-1, DEN-2 and DEN-3 serotypes in major Brazilian cities and the co-circulation of different serotypes has led to the first cases of dengue hemorrhagic fever (DHF). This study had as objectives: Isolate in cell culture samples of dengue virus circulating in the state of Amazonas; identify the serotypes of the dengue virus through sorologicas and molecular techniques; to correlate the clinical and laboratory most important cases of dengue, of dengue hemorrhagic fever (DHF) and dengue by shock syndrome (DSS), with each serotype; comparing the results obtained through the sequencing parcial of genes C and prM of samples of dengue found in this study compared with the sequences deposited in GenBank. Between January 2005 and June 2007, 534 blood samples were collected from patients with clinical symptoms of dengue fever who were negative for malaria. Anti-dengue immunoglobulin M (IgM) specific antibodies were detected in 90 (16.8%) samples, from those 40 (44.4%) were PCR-amplified, 13 (32.5%) were typed as DEN-2, 23 (57.5%) as DEN-3 and 4 (10%) as DEN-4. Among the 40 PCR-positive samples, 52 (57,7%) were also positive for viral culture. DEN-3 was isolated from two patients diagnosed with hemorrhagic fever by the WHO criteria. As this work reports the first detection of dengue type 4 viruses in Amazonas, DEN-4 was identified from the sera of three patients with co- infection two of them were DEN-3/DEN-4 co-infection and one DEN-2 / DEN-4. A greater incidence of DEN-3 in relation to DEN-2 and DEN-4, and the absence of DEN-1 circulation.