Clinical presentations and diagnosis of brucellosis

Brucellosis is a worldwide zoonosis caused by Brucella species. The disease remains a significant economic and public health problem particularly in the Mediterranean countries. Clinical manifestations of brucellosis are variable and often nonspecific, simulating infectious and noninfectious diseases. Osteoarticular involvement is the most common focal complication of brucellosis and morbidity. Mortality rate due to brucellosis is low, mostly secondary to endocarditis and central nerve involvement of disease. The diagnosis of brucellosis depends on the clinical presentations and laboratory tests. Detection of Brucella species by culture method is sometimes unsuccessful; therefore, serological tests are preferred. These tests are easy to perform, and results can be obtained within a short span of time. Several serologic tests have been developed for the diagnosis of human brucellosis, including the standard agglutination tube (SAT) test, anti-human globulin (Coombs) test, indirect fluorescence antibody (IFA) test, and enzyme-linked immunosorbent assay (ELISA). SAT is the primary test used in many clinical laboratories. IFA and ELISA are simple and reliable for the detection of immunoglobulin classes especially in complicated cases. Polymerase chain reaction (PCR) technique is highly sensitive and specific for the determination of Brucella spp. from peripheral blood and other tissues. Recent patents are especially based on molecular assays in the diagnosis of brucellosis. However, PCR is still expensive and may not be appropriate for daily practice.