Development and Validation of a Multivariate Serum Biomarker Panel for Early Diagnosis of Bovine Tuberculosis in Cattle Herds in Borno State, North East Nigeria

Bovine tuberculosis caused by Mycobacterium bovis remains a significant zoonotic and veterinary public health concern in Nigeria, and the inadequacy of single-test diagnostic approaches under field conditions necessitates development of multivariate biochemical diagnostic tools. This doctoral study developed and validated a multivariate serum biomarker panel for early diagnosis of bovine tuberculosis in cattle herds in Borno State, North East Nigeria, addressing a recognised gap in accessible serological tools for resource-limited settings. One hundred and twenty Zebu cattle from tuberculosis-endemic herds were enrolled, with confirmed cases identified by intradermal tuberculin test, interferon-gamma release assay, and post-mortem pathological examination. Serum candidates assessed included IP-10, interleukin-2, haptoglobin, C-reactive protein, adenosine deaminase activity, lysozyme, and neopterin. Discriminant function analysis and least absolute shrinkage and selection operator regression were used to develop and validate the multivariate panel. A four-marker panel comprising IP-10, adenosine deaminase, interleukin-2, and neopterin achieved diagnostic sensitivity of 89% and specificity of 93% in cross-validation, outperforming any single analyte. Area under the receiver operating characteristic curve was 0.96. The panel showed no cross-reactivity with Johne's disease or brucellosis sera. Implementation of the panel in a two-stage screening algorithm with the tuberculin skin test is proposed. These original contributions provide a validated, deployable biochemical diagnostic tool for bovine tuberculosis surveillance in North East Nigeria and hold potential for broader continental application. Keywords: bovine tuberculosis, multivariate biomarker panel, IP-10, adenosine deaminase, Borno State.