Simultaneous circulation of all four dengue serotypes in Manaus, State of Amazonas, Brazil in 2011

Manaus, the capital city of the state of Amazon with nearly 2 million inhabitants, is located in the middle of the Amazon rain forest and has suffered dengue outbreaks since 1998. In this study, blood samples were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), aimed at identifying dengue virus serotypes. Acute phase sera from 432 patients were tested for the presence of dengue virus. Out of the 432 patients, 137 (31.3%) were found to be positive. All the four dengue virus serotypes were observed. The simultaneous circulation of the four dengue serotypes is described for the first time in Manaus and in Brazil.