There has recently been an uptick in media reports focused on the threat of the mosquito-borne dengue virus in the US. The latest is an article, in which I am quoted, that details the mosquito control efforts of California, a state where no cases have been detected.
Until this year, local spread of dengue was know to have occurred in Texas (chiefly along the border with Mexico), Florida, and Hawaii, the details of which can be found in a paper my colleagues and I wrote on the topic. This year, however, in addition to the uncovering of evidence of local spread in Houston, a locally-acquired case was detected in New York.
The key thing to remember with respect to dengue is that since the Aedes mosquito is present over a large swath of the US and there are a continual stream of potentially infected travelers--who may be asymptomatic--it is not surprising to find instances of local spread of dengue occurring in the US. In fact, serosurveys along the Texas-Mexico border have shown up to 40% of individuals exhibit evidence of exposure to dengue.
Clinicians and public health officials should keep these facts in mind when investigating or treating unexplained febrile illnesses.