Simultaneous circulation and coinfection of Dengue clades and serotypes in Southern Brazil

Dengue is an arthropod-borne virus with worldwide urban transmission mediated by anthropophilic vectors of the genus Aedes. Currently, there is a substantial genotype diversity that belongs to at least four known serotypes. Tropical regions, where several serotypes cocirculate in the population, are hyperendemic, driving multiple outbreaks with variable disease manifestations. Notably, the Dengue virus burden is increasing in subtropical and temperate regions of the globe due to climatic changes associated with new outbreaks in naive and previously unaffected human populations. The introduction and endemic transmission of different clades and serotypes in these regions is highly concerning due to the known and still unknown consequences of Dengue infection on populations with diverse genetic backgrounds. Here, we characterized the coinfection of different Dengue clades and serotypes in Rio Grande do Sul, Brazils southernmost and subtropical state, by combining serotype-specific RT-PCR and deep sequencing. We found five coinfected patients in four municipalities where these clades and serotypes circulated simultaneously. Our data suggests that coinfection events account for a minority of total cases, but these findings may reflect the early transmission phases of some Dengue clades. Hence, close monitoring is warranted to evaluate coinfection rates and associated clinical consequences as clade prevalence changes.