Document Type : Original Article
Department of pathobiology, faculty of Veterinary Medicine, Ferdowsi University, Mashhad, Iran
Department of Pathobiology, Faculty of Veterinary medicine, University of Mashhad, Mashhad, Iran.
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 have still been isolated from livestock farms across the country. Having a test with 100% sensitivity and specificity are essential features for a bovine tuberculosis diagnostic test. The relationship between real-time PCR and Immunohistochemistry (IHC) as two essential laboratory methods in the diagnosis of bacterial infections was aimed at evaluating 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%) cows were Mycobacterium bovis positive, 46 (43%) cows were Mycobacterium avium subsp. paratuberculosis (MAP) positive, and 11 (10%) were Mycobacterium tuberculosis positive. 32 (55%) cows co-infected with M. bovis and MAP, and 5 (45.5%) cows were co-infected with Mycobacterium tuberculosis and MAP in this group. Of 50 M. bovis negative cows of reactor group were 14 (28%) MAP positive, and 36 (72%) negative too. 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). The results also provide further confirmation of IHC and real-time PCR as a sensitive and reliable diagnostic screening approach for the detection of bovine tuberculosis. The use of one laboratory method to detect bovine tuberculosis is not sufficient alone.