Florida has recorded 485 dengue cases this year, surpassing its previous annual high, according to the Centers for Disease Control and Prevention. The tally was 228 two weeks earlier.

Hillsborough County has reported 230 cases, the most in the state, while Miami-Dade has reported 157. Broward has recorded 19 and Palm Beach 13. Hillsborough officials declared a state of emergency on Sept. 24 to give the county more financial flexibility for mosquito-control efforts.

Dengue is a mosquito-borne viral infection. Most infections cause mild symptoms or none, but severe illness can occur. The CDC listed 2,145 U.S. cases as of Sept. 30, including Florida’s 485; nationally, 42% of reported cases had led to hospitalization.