What to know about dengue fever after Florida officials warn of cases

Florida health officials are warning residents about the risks of mosquito-borne illnesses after five cases of dengue fever were reported this month in a part of the United States where locally acquired cases are rare.

Broward and Miami-Dade counties are under mosquito-borne illness alerts after the cases were reported there, and health officials advised residents to take steps to prevent mosquito bites, such as draining standing water and wearing repellent.

Although about half of the world’s population is at risk of dengue, according to the World Health Organization, most U.S. states see little to no locally acquired cases. Most U.S. cases are either brought in by travelers to the continental United States or occur in the U.S. territories. The WHO has warned that global warming could prompt record numbers of infections worldwide.

Many cases of dengue — also known as breakbone fever — are mild or even asymptomatic, but severe cases can be fatal.