State of Florida Department of Health and Rehabilitative Services, Division of Field Services, Epidemiology Program Office, Centers for Disease Control and Prevention, Division of Vector-Borne Viral Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Tallahassee, Florida
From July 10 through August 4, 1980, five cases of St. Louis encephalitis (SLE) occurred in and near Fort Walton Beach on the Gulf Coast of northwest Florida. These were the first cases of SLE ever reported from the Florida panhandle. To determine the extent of SLE infection in the community, sera (n = 968) were collected from patients at the local hospital and county public health unit and tested for SLE virus antibody. The SLE attack rate was highest in a centrally located impoverished census tract. There was a trend toward decreasing seroprevalence with distance from the central area of the city. Overall, seroprevalence was higher in males (prevalence ratio = 2.7) and in all areas, seroprevalence increased with age. The serosurvey results suggest that SLE has been endemic in the Fort Walton Beach area.