Brucellosis rarely can present with involvement restricted to the nervous system. We describe a total of 19 cases of neurobrucellosis in whom the clinical presentation lay in three distinct categories. The first was an acute presentation with meningoencephalitis. The disease also presented in a chronic form where the brunt of the illness can either be in the peripheral or the central nervous system (CNS). The chronic peripheral form is that of a proximal polyradiculoneuropathy. The central form is that of diffuse CNS involvement, predominantly with myelitis or cerebellar involvement with or without cranial nerve palsies. Although the two chronic forms, 'peripheral' and 'central', are distinct, some overlap is possible. This was not observed for the acute form. The pathology of the three presentations may be different, being a direct effect of infection in the acute form, and an immune-related process, possibly demyelinating in nature, in the chronic forms. The response to treatment in the acute and chronic forms is also different, being much better in the acute form. Awareness of the condition and performance of the appropriate serological tests will differentiate neurobrucellosis from other chronic CNS infections, especially tuberculosis and neurosyphilis.

Of 400 patients with bruceilosis, 104 (26%) had arthritis, of whom 96 could be followed up. The systemic disease in the 96 patients was acute in 54 (56%), subacute in 24 (25%), and chronic in 18 (19%). The main presenting symptoms were joint pain, fever, sweating, and easy fatigability. The joints most commonly affected were the sacroiliac joint (26%) and knee (25%) followed by hip (18%) and spine (8%

SUMMARYAn enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of brucella-specific IgG, IgM and Brucella ELISA immunoglobulins (Ig) were detected in some individuals in the control groups but the majority of these had titres of < 100 for IgG, IgM, and IgA. However, patients with brucellosis had significantly higher ELISA titres in all classes of Ig than controls but the sensitivity and specificity within each Ig class varied with the titre considered. At a titre of > 1600 the brucella IgG had a sensitivity and specificity of 98 % for patients with acute or chronic brucellosis; this decreased with lower reciprocal titres. The brucella IgM titre of > 400 had a sensitivity of 98 % and a specificity of 98 % for patients with acute brucellosis.However, in patients with chronic brucellosis the brucella IgM was very low. The brucella IgA titre of > 200 showed a sensitivity of 98 % and a specificity of 99 % for patients with either acute or chronic brucellosis. This study indicates that brucella ELISA is a rapid, sensitive and specific assay, provides a profile of Ig classes in the diagnosis of acute and chronic brucellosis, is useful for mass screening and could be considered the method of choice for the serological diagnosis of brucellosis.

Sera from patients in different stages of brucellosis as well as sera and cerebrospinal fluid (CSF) from patients with central nervous system (CNS) brucellosis and controls, were tested by ELISA for Brucella‐specific IgG, IgM and IgA. The results were compared with culture findings, micro‐agglutination (MA), slide agglutination with Rose Bengal (RB), and Brucella melitensis stained antigens (SA). In sera of patients with acute brucellosis (296), ELISA was positive for IgM (100%), IgG (97%) and IgA (98%), and comparable results were found in sera of patients with subacute brucellosis (44): IgG (100%), IgM (86%) and IgA (100%). However, in patients with chronic brucellosis (40), IgG and IgA were consistently positive (100%) while IgM was only positive in 33% of their sera. The MA and RB showed similar results, being more positive in patients with acute (98%) and subacute (84%) than in chronic (61%) brucellosis. The SA and culture showed significantly lower positive results. In the CSF of patients with CNS brucellosis (45), ELISA was positive in 100%, 20% and 85% for IgG, IgM and IgA, respectively, compared to 13% positive by culture, 25% by MA and 22% by RB. ELISA was negative in the CSF specimens from patients with brucellosis without CNS involvement (66), or meningitis other than Brucella (62), and no meningitis (144). Thus, ELISA with its IgG, IgM and IgA profiles is the test of choice in the diagnosis of patients with brucellosis, especially those with chronic or CNS infection.