Assessing parallel testing to improve detection of bovine tuberculosis at a slaughterhouse in Lahore, Pakistan

The current study was designed to evaluate the reliability of the interferon-gamma release assay (IGRA) as a screening test compared to intensive post-mortem inspection using agreement analyses. This study also aimed to determine the prevalence and risk factors of bovine tuberculosis (bTB) among bovines presented for slaughter in the largest abattoir in Lahore, Pakistan. After antimortem inspection, a total of 102 animals were randomly selected for sample and data collection. Selected animals were slaughtered and a thorough post-mortem examination was done for all carcasses to find TB-like lesions. Blood samples were processed by IGRA. Prevalence estimates were generated and Cohen’s Kappa test was done for agreement analyses to compare the reliability of the two tests for bTB diagnosis. A substantial agreement (κ = 0.79) was estimated between the IGRA and intensive post-mortem inspection. The apparent prevalence was computed as 5.88% (95% CI; 2.59–11.97) and the true prevalence was estimated as 3.92% (95% CI; 1.35–9.47). A parallel testing strategy with IGRA and intensive post-mortem inspection is a useful approach for screening bTB.