Comparison of Various Rose Bengal Plate Tests, Serum Tube Agglutination Tests, and Enzyme-Linked Immunosorbent Assays Used in Brucellosis Serosurveillance in Sheep, Bovines, and Spotted Deer

Brucellosis is a zoonotic disease causing significant economic losses, and necessitating standardized diagnostic kits for effective surveillance. The objectives of this study are to investigate brucellosis serosurveillance in ruminants, and to evaluate three serological tests—Rose Bengal Plate Tests (RBPTs), Serum Tube Agglutination Tests (STATs), and Enzyme-Linked Immunosorbent Assays (ELISAs)—each from three manufacturers. A total of 5797 serum samples (5260 sheep, 83 bovines, and 454 spotted deer) were initially screened with the RBPT, and 54 RBPT-positive selected samples were subsequently analyzed by the STAT and ELISA. RBPT screening showed significant variability: kit A (0.86%) showed significantly lower positivity than kits B and C (1.45% and 1.43%, p < 0.05). Among 54 RBPT-positive samples, STAT positivity from manufacturers A, B, and C was 61.11%, 70.37%, and 66.67%, respectively, with no significant differences (p > 0.017 in pairwise comparisons). All ELISAs consistently outperformed STATs. Kit B (competitive ELISA, 90.74%) had significantly higher positivity than kits A (indirect ELISA, 77.78%) and C (competitive ELISA, 74.07%) (p < 0.017 in pairwise comparisons). Key implications: Results from different manufacturers are not directly comparable, and concurrent use of different techniques on the same sample can yield discrepant outcomes. This underscores the urgent need for diagnostic kit standardization in brucellosis prevalence studies.