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

introduction: 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. methods: in this study, blood samples were investigated using reverse transcriptase-polymerase chain reaction (rt-pcr), aimed at identifying dengue virus serotypes. results: 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. conclusions: the simultaneous circulation of the four dengue serotypes is described for the first time in manaus and in brazil.