State health officials reported this week that more than 250 locally acquired cases of the mosquito-borne disease have been tallied so far this year. The vast majority of them were in Hillsborough County, home to Tampa.

Federal health officials say their data on dengue outbreaks is limited. But available information from state health departments and medical journals suggests the Florida outbreak marks the most cases in a calendar year for any state since at least the 1940s.

Puerto Rico is consistently hit hard by dengue, with numbers much higher than what’s seen in any of the 50 states. But in the continental U.S., Florida usually gets the most locally transmitted cases. The state’s previous worst year was 2023, when just under 200 locally spread cases were reported.

Officials in Hillsborough and surrounding counties have declared local emergencies, and workers in the Tampa area are spraying day and night to tamp down the population of disease-transmitting mosquitoes.