Dengue fever has surpassed 500 cases in the United States in 2026, following a record-breaking 2024 that saw 3,798 confirmed cases reported to the CDC's ArboNET surveillance system, a 359 percent increase above the 2010 to 2023 annual average. The mosquito primarily responsible for spreading the virus, Aedes aegypti, is now confirmed to be expanding its range northward into states well beyond its traditional subtropical stronghold. And this summer, the window for local transmission risk extends further into the continental United States than it did a decade ago.
Public health authorities, entomologists, and infectious disease specialists are tracking the shift with concern. Dengue is not simply a travel disease any longer for Americans. While the vast majority of cases remain travel-associated, the conditions enabling local transmission are broadening with each passing season.
