A woman was recovering from the disease, officials said, as they urged the public to take precautions against mosquitoes that carry tropical diseases, the South Florida Sun Sentinel reported Wednesday.
"Today's West Nile virus confirmation in a resident serves as a reminder for people to avoid mosquito bites," said Dr. Alina Alonso, director of the Palm Beach County Health Department.
The infected woman, who was not identified, was briefly treated in a hospital for her symptoms in November but was recovering at home, department spokesman Timothy O'Connor said.
West Nile is carried by Culex nigripalpus mosquitoes, which breed in standing water, authorities said.
The virus generally causes a mild headache, flu-like symptoms and the telltale stiff neck, and while most people have mild or even no symptoms, severe cases can cause disorientation or death, O'Conner said.