Comparative Evaluation of ELISA Tests for Bovine Tuberculosis Detection: Implications for Improved Disease Control

Accurate diagnosis of bovine tuberculosis (bTB) remains a critical challenge for disease control and eradication programs. While cell-mediated immune (CMI) response tests such as the comparative cervical intradermal tuberculin test (CCITT) are widely used, their sensitivity is limited, especially in later stages of infection. Antibody-based assays, such as enzyme-linked immunosorbent assays (ELISAs), may offer complementary detection and improve case identification. This study aimed to comparatively evaluate two indirect ELISA tests for the detection of antibodies against Mycobacterium bovis in naturally infected cattle from Southern Brazil. One ELISA test is in an experimental phase and uses a chimeric antigen comprising fragments of MPB70, MPB83, and ESAT-6 proteins. The second is a commercially available ELISA registered with the WOAH, based on MPB70 and MPB83 antigens. Serum samples were collected from 147 cattle across nine herds with known bTB epidemiological histories. All animals underwent CCITT, and a subset was subjected to post-mortem examination, culture, and nested-PCR. The experimental ELISA identified 16.6% of animals as seropositive, while the commercial ELISA identified 13.0%, both exceeding the 4.4% apparent prevalence detected by CCITT. Both ELISAs showed low sensitivity (<30%) when compared to culture or PCR-confirmed cases but were able to detect additional infected animals missed by CCITT. These findings support the use of serological tests as complementary tools to enhance bTB detection in cattle and inform surveillance and eradication strategies in endemic regions.