Brucella suis infection in Philadelphia. A survey of hog fever and asymptomatic brucellosis.

Examination of hospital and public health records revealed 19 cases of brucellosis diagnosed in Philadelphia between 1968 and 1972. A serologic survey at Philadelphia's largest hog-processing plant, however, indicated infection in 39% of workers. If extrapolated industry-wide, the total would be several hundred in Philadelphia. The infection is usually unrecognized or asymptomatic, since men were active in physically demanding jobs with agglutinin titers in excess of 1:5000. Overt illness, usually first diagnosed after weeks of incapacity, responded readily to tetracycline therapy. Although clinical manifestations are nonspecific, attention to occupational history should quickly lead to the diagnosis. It is emphasized that any hog-processing plant, wherever located, is potentially a reservoir of brucellosis. Prolonged morbidity and loss of production time might be avoided if physicians were more alert to this infection. Agglutinins in possibly significant titers were also found in a small fraction of persons without identifiable exposure.