Outbreak of brucellosis at a South-Australian abattoir. 1. Clinical and serological findings.

During the period October 1979 to May 1980, 22 cases of acute brucellosis occurred at a South Australian abattoir. We obtained blood samples for serological investigations and culture of Brucella abortus, and tested the sera using the standard agglutination test (SAT), dithiothreitol test (DTT), anti-human globulin test (AHG) and complement fixation test (CFT). Patients showed large variations in antibody levels in each of these tests, both on presentation and after treatment. Blood culture was successful in six of 15 patients in whom it was attempted. Using the experience gained during the outbreak, we defined a set of serological criteria for the diagnosis of acute brucellosis, particularly in those who are occupationally exposed.