Faculty of Veterinary Medicine, Urmia University Veterinary Research Forum 2008-8140 13 2 2022 06 15 Performance of immunohistochemistry vs real-time PCR methods for detecting mycobacterial infections of cattle screened by comparative tuberculin test 223 231 248051 10.30466/vrf.2020.122038.2871 EN Hossein Nourani Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran Mojtaba Ashouri Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran Journal Article 2020 03 02 In addition to the fifty years since the test-and-slaughter program began in Iran and despite a significant reduction in the disease prevalence, positive tuberculosis cases are still being isolated from livestock farms across the country. Tests with 100% sensitivity and specificity are essential features for bovine tuberculosis diagnosis. The relationship between real-time PCR and immunohistochemistry (IHC) as two essential laboratory methods in the diagnosis of bacterial infections were aimed to evaluate single intradermal comparative tuberculin test (SICTT) results. One hundred thirty-eight cows in two groups were examined: Reactors (108 cows) and clean (as a control group; 30 cows). In the reactor group, 58(54.00%) cows were Mycobacterium bovis positive, 46(43.00%) were Mycobacterium avium subsp. paratuberculosis (MAP) positive, and 11(10.00%) were Mycobacterium tuberculosis positive. 32(55.00%) cows were co-infected with M. bovis and MAP and 5(4.55%) cows were co-infected with Mycobacterium tuberculosis and MAP in this group. Of 50 M. bovis negative cows of reactor group were 14(28.00%) MAP positive and 36(72.00%) negative, as well. Concurrent infection with all was observed in one reactor case. Comparing IHC and real-time PCR for the detection of bovine tuberculosis and Johne’s disease showed very good agreement (Kappa values 0.81 - 1.00). The results also provided further confirmation on IHC and real-time PCR as a sensitive and reliable diagnostic screening approach for detection of bovine tuberculosis. The use of one laboratory method to detect bovine tuberculosis is not sufficient alone.

https://vrf.iranjournals.ir/article_248051_5cef43602bc7486da26ba5fbf4483f43.pdf