Diagnosis of human brucellosis with ELISA

ELISA tests for total (IgG + IgM + IgA), IgG, and IgM anti-Brucella antibodies, which utilised only commercially available reagents, were used to diagnose human brucellosis. Assays for total antibodies in sera from 22 patients with confirmed acute brucellosis, 1 patient with probable acute brucellosis, and 3 patients with probable chronic brucellosis gave readings that were more than double those found in hundreds of control sera. All sera from patients with acute and chronic brucellosis had significantly elevated IgG levels. Although there were a few acute patients with IgM levels only slightly higher than those of some controls, most patients with acute disease could readily be differentiated from both the non-brucellosis patients and patients with chronic brucellosis by measuring macroglobulins. Both the IgG and IgM levels of sera from acute patients persisted for at least 8 months. The results of this show that ELISA is an excellent method for screening large populations for Brucella antibodies and for differentiation between the acute and chronic phases of the disease.