Follow-up studies of st. Louis encephalitis in Florida: sensorimotor findings.

THREE outbreaks of St. Louis Encephalitis (SLE) virus infections occurred in the Tampa Bay Area of Florida in the years 1959, 1961, and 1962. Of these, the largest was the 1962 epidemic during which 222 clinically and/or serologically confirmed cases with 43 fatalities were reported.' Of the four counties surrounding Tampa Bay (Pinellas, Hillsborough, Manatee, and Sarasota), Pinellas with one-fourth of its population 65 years of age or older, according to the 1960 United States Census, was affected the most by these SLE outbreaks. This afforded the opportunity for a study of SLE sequelae in the largest population of elderly individuals since the first recognized epidemic occurred in St. Louis, Mo.23 Of the 166 confirmed 1962 cases of SLE in Pinellas County, 131 (79 per cent) were individuals 45 years of age or older and 86 (52 per cent) were persons 65 or over (Table 1). All of the fatalities were in patients over the age of 50.4 This substantiated the findings of the earlier reports2'5 that the incidence, mortality, and morbidity rates from SLE increase with age in contrast