Abstract
In this study, 6150 animals (3600 dairy cattle and 2550 buffaloes) in different Egyptian governorates were tested by single intradermal cervical tuberculin test using purified protein derivatives - bovine type (PPD-B), 72 cattle (2%) and 26 buffaloes (1%) reacted positively. The postmortem examination of the positive reactors revealed 49 (68.1%) out of 72 slaughtered cattle with visible lesions (VL) while the other 23 (31.9%) reactors showed no visible lesions (NVL); comparing with 17 (65.4%) out of 26 slaughtered buffaloes with VL while the other 9 (34.6%) reactors showed NVL. The bacteriological examination of processed samples from the 72 slaughtered cattle revealed 44 Mycobacterium bovis (61.1%); 40 (81.6%) were from 49 VL and 4 (17.4%) were from 23 NVL, compared to 15 (57.7%) Mycobacterium isolates from buffaloes; 10 (38.5%) were M. bovis, all were from the 17 VL (58.8%), and 5 isolates (19.2%) were Mycobacterium other than tuberculosis (MOTT), 3 (17.6%) were from the 17 VL and 2 (22.2%) were from the 9 NVL. The ESAT6-CFP10 mixture using ELISA of the tuberculin positive animals sera showed VL could detect 83.7% and 70.6% in cattle and buffaloes, respectively; compared to 89.8% and 76.5% in cattle and buffaloes, respectively using PPD-B. On the other hand, the sera collected from tuberculin positive animals with NVL, the antigen mixture revealed 17.4% and 22.2% in cattle and buffaloes, respectively, using the ESAT6-CFP10 mixture; compared to 21.7% in cattle and 33.3% in buffaloes using the PPD-B antigen. The PCR assay using oligonucleotide primer that amplifies a 350 bp fragment in RD7 region of M. bovis confirmed the cultural and biochemical identification of M. bovis isolates (PCR-positive) and MOTT (PCR-negative).