Trends of brucellosis in Florida. An epidemiologic review

Human brucellosis in Florida is documented for the 47-year period 1928-1975. Of the 936 cases reported in 1930-1975, more than half (505) occurred in the decade 1940-1949. The incidence declined rapidly to an average rate of five cases per year, although there was an increase in 1974 and 1975. The analysis is mainly concerned with the years 1961-1975, since more complete epidemiologic data are available for this period. Cases occurred throughout the year, with the highest incidence being between May and August. White males in the 25-35 and 35-44 deciles were most affected. Of occupations identified between 1963-1975, 44% were related to the livestock-producing industry, 16% to the meat processing industry and 28% to hunters, housewives, students and children. Twelve per cent of the cases did not fall in any of these categories. Cattle were the most probable source of human infection in the livestock industry, and swine were associated with most non-industry cases. In 1963-1975, B. suis was isolated from 10 cases and B. canis from one case; one other isolate was not identified beyond genus. Of the 27 human cases recorded during 1974-1975, 15 (56%) involved swine contact (five livestock industry, four consumers and six hunters), 11 (41%) involved cattle contact (all from the livestock and meat packing industries), and one involved contact (with both cattle and swine (livestock industry). Human cases contracted from swine were scattered statewide, whereas cases associated with cattle only occurred in counties that had )( high densities of cattle and 2) modified-certified ratings in the Brucellosis Eradication Program.