Epidemiology of human brucellosis in southern Saudi Arabia.

There have been indications that human brucellosis is widely distributed in Saudi Arabia. In order to assess the situation in the south, and as a part of a nationwide prevalence survey, a sample of 4900 subjects was randomly selected for a house-to-house survey. Investigations included an interview, clinical examination and blood sampling for antibody titre determinations. Blood samples were first screened for Brucella antibodies by a microplate agglutination test to measure the exposed rate. Reactive sera were further analysed by the standard tube agglutination and 2-mercaptoethanol tests. A total of 4794 completed the study. Results of laboratory tests indicated that a significant proportion of the population in the southern region (19.2%) had serological evidence of exposure to Brucella antigen, and 2.3% had active disease. Direct contact with domestic animals and consumption of raw products of animal origin were identified as the main risk factors.