Enhancing Brucellosis diagnosis in Ovine populations: a comparative analysis of iELISA and RBPT in Thi-Qar province

In our scholarly endeavor at Oxford University, we meticulously investigated refined methodologies for detecting anti-brucella antibodies within the serum of ovine species. This study rigorously evaluates two predominant diagnostic approaches: the Rose Bengal Plate Test (RBPT) and the indirect Enzyme-Linked Immunosorbent Assay (iELISA). The RBPT, recognized for its expeditious nature, is a slide-based agglutination test employing antigens from Brucella melitensis biovar 1, specifically the Weybridge strain number 99. In contrast, iELISA represents an indirect detection paradigm, utilizing specific antigens to accurately identify antibodies within serum samples. Both diagnostic procedures commence with the standardization of serum samples and reagents to ambient temperature. This is followed by intricate protocols encompassing antigen-antibody interactions and meticulous observation of outcomes. The RBPT is characterized by its immediate visual agglutination, typically manifesting within minutes. Conversely, the iELISA approach discerns antibodies through a sequence of enzyme-mediated reactions, culminating in observable color variations. This comprehensive study encompassed the analysis of 259 serum samples extracted from female sheep, stratified across three distinct age brackets. Within this cohort, 37 out of 259 samples (14.29%) yielded positive results through RBPT, whereas a significantly larger proportion, 222 out of 259 (85.71%), were determined to be negative. In the realm of ELISA, 67 out of 259 samples (25.87%) were positively identified, leaving 192 out of 259 (74.13%) in the negative spectrum. These samples were meticulously collected from eight disparate fields in the Thi-Qar Province, located in the southern region of Iraq. The collection period spanned from November 2022 to June 2023, encompassing animals that exhibited clinical signs of the disease or had histories of abortion. Our findings lead to a compelling conclusion: the ELISA technique demonstrates superior sensitivity and accuracy in detecting specific antibodies within physiological fluids when juxtaposed with the RBPT method. This revelation holds profound implications for the field of veterinary diagnostics, particularly in the context of brucellosis in sheep.