Seroprevalence of Human Brucellosis in Wadi Al Dawaser region of Saudi Arabia.

Background and Objective: Brucellosis is an important zoonotic disease and a major public health problem in the Middle East countries including Saudi Arabia. This study has evaluated the seroprevalence of human brucellosis in Wadi Al Dawaser region of Central Saudi Arabia. Methods: The study was conducted for three years (2015-2018) at Wadi Al Dawaser general hospital. A total of 6721 clinically suspected serum samples were collected over three years and tested by Rose Bengal Plate Test (RBPT), Serum Agglutination Test (SAT), IgM and IgG ELISA. A standard questionnaire to determine the risk factors were used among patients. Results: Of the total 6721 samples tested, 576 (8.6%) were seropositive for brucellosis. RBPT identified 427 (74.1%), SAT titers 493 (85.6%) cases. IgM ELISA and IgG ELISA were positive for 501 (86.9%) and 558 (96.8%) cases respectively. Among the positive cases, 77.3% were male with the male to female ratio of 3.3:1. Nearly, 82% were Saudi Nationals. Direct contact with domestic animals and consumption of raw milk were the risk factors identified. No seasonal variation was seen. Diagnostic yield of IgM ELISA showed 86.9% sensitivity and 100% specificity; IgG ELISA showed 96.8% sensitivity and 100% specificity. Both IgG and IgM ELISAs showed 100% Positive predictive value, 98.9% and 95.6% Negative predictive value respectively. Conclusion: A seroprevalence of 8.6% of human brucellosis was documented from this rural region. This is the first report from Wadi Al Dawaser. Frequent surveillance among risk group, vaccination of livestock, creating awareness and health education among the public and school children are recommended.