Rapid diagnosis of central nervous system brucellosis by ELISA

The diagnosis of central nervous system (CNS) brucellosis was made by determining Brucella-specific IgG, IgM and IgA in cerebrospinal fluid (CSF) specimens, using an enzyme-linked immunosorbent assay (ELISA) method. A total of 68 CSF specimens including 10 from patients with brucellosis of the nervous system, 4 with Brucella infection but without CNS involvement, 38 with meningitis other than due to Brucella and 16 with no meningitis were studied. Of the 10 CSF specimens from patients with CNS brucellosis, Brucella-specific IgG was detected in all 10, IgM in 7 and IgA in 8. The 10 patients were also seropositive for anti-Brucella IgG and IgM, and 9 were seropositive for IgA. No Brucella-specific IgG, IgM or IgA was detected in the CSF of 4 patients with brucellosis but without CNS involvement, even though the blood of these patients had high titres of anti-Brucella IgG, IgM and IgA. In addition, none of the CSF specimens from the 38 patients with meningitis other than due to Brucella, or from the 16 patients without meningitis, had detectable anti-Brucella antibodies. This study indicates that the Brucella ELISA on CSF is a reliable, rapid, sensitive and specific assay in the diagnosis of CNS brucellosis.