Northern Queensland DENV outbreaks, 1990-2017.

(A) Timeline summarising the occurrence of northern Queensland outbreaks between 1990 and 2017 based on circulating DENV 1-4 serotypes. The sustained DENV-3 outbreak in 1997-1999 is represented by the elongated ellipse symbol. (B) The number of northern Queensland outbreaks occurring between 1990 and 2017 are plotted against the location (specific country or broader regional classification excluding specific country data, based on phylogenetic analysis) of the most likely geographical source. Data in both (A) and (B) includes secondary outbreaks which resulted from further spread of imported DENV strains into new Queensland locations.<br>