RESUMEN
One hundred and thirty seven [4.6%] out of 3000 cattle at different ages from seven governorates of Egypt [Qualubia, Sharkia; Gharbia, Giza, Behira, Sohag and Ismailia] were found positive for tuberculosis by single inradermal [SID] tuberculin Bacteriological examination of tested samples from slaughtered reactor cattle revealed the isolation and identification of Mycobacterium bovis [M. bovis] and Mycobacterium other than tuberculosis [MOTT] in 90 [65.7%] and 7 [5.1%] samples, respectively. One hundred and eight [78.83%] serum samples out of 137 tuberculin reactors were found positive for enzyme linked immunosorbent assay [ELISA] by using test. Post mortem [PM] examination of slaughtered reactor cattle revealed tuberculous visible lesions [VL] and non-VL [NVL] in 94 [68.6%] and 43 [31.4%] animals, respectively. Tuberculous lesions were observed in 41 29.9%], 19[13.9%], 20 [15%] and 14 [10.2%] in 137 slaughtered reactor cattle with pulmonary, digestive, mixed and generalized VL, respectively. M.bovis synthetic early secretory antigenic target 6 peptide antigen [ESAT6-p]. Polymerase chain reaction [PCR] amplification assay was performed on selected tissues samples from 10 slaughtered tuberculin reactors with pulmonary, digestive, mixed or generalized VL, or NVL. Eight [80%] out of the 10 samples gave positive results with PCR assay. On the other side, only 6 [60%] and 7 [70%] of these samples were found positive for M.bovis isolation and ELISA, respectively. The results obtained in the present study point to the importance of the periodical tuberculin testing of animals, use of ELISA assays with M.bovis-specific antigens as a complimentary diagnostic toot to tuberculin test and application of PCR test for direct and rapid diagnosis of tuberculosis. Improvement of diagnostic assays for M.bovis may be of value in the effectiveness of test and slaughter eradication programs of bovine tuberculosis in governorates of Egypt