Highlighting on Bovine Tuberculosis infection in cattle

This work was directed to isolate the mycobacterium tuberculosis complex from the infected samples (positive or suspicious reactor to tuberculin test) and evaluate the ELISA and PCR assays for the diagnosis of bovine tuberculosis as well as to ascertain the changes in hematological and biochemical constituents of blood as a result of mycobacterium tuberculosis infection in cattle.
A total of 500 animals from private cattle farm and abattoir aged between 2-5 years were tested by tuberculin test during the period from April  2019 to October 2021 at Sharkia Governorate (360 positive tuberculin test and 140 negative tuberculin test). Blood and lymph nodes were collected for bacteriological examination, Elisa assay and molecular identification of mycobacterium tuberculosis complex.
For hematological and biochemical investigation. A total of 60 blood samples were collected with and without heparin from animals showing negative tuberculin test (group l). Moreover, 120 blood samples were collected with and without heparin from animals showed positive tuberculin test without lesions (group 2) and with lesions (group 3) 60 for each.
The obtained results showed that 210 samples were found positive for bovine tuberculosis by traditional culture method with a percentage of isolation reached 58.3% while the presence of acid fast bacilli of the same tested samples reached 219 samples with a percentage of 60.8% The results of ELISA assay for detection of mycobacterium antibodies in sera of tuberculin positive animals were reported and the results showed that , 313 out of 360 samples  harbored mycobacterium antibodies with a percentage of 87% while the results of tuberculin negative animals showed the presence of mycobacterium antibodies in sera of 16 tuberculin negative animals out of 140 animals with a percentage of (l I .4%). The results of RT PCR were recorded, which showed that 184 out of 210 isolates of mycobacterium spp. proved to be mycobacterium bovis with a percentage of (87.6%).
Concerning hematological examination there is a significant decrease in total red blood cells count. and hemoglobin concentration (P < 0.05) accompanied by higher values of Total leukocyte count (TLC) lymphocyte, eosinophil. monocytes and lowered neutrophil count recorded in infected and contact cows compared to control group. The obtained results indicated that there was a significant increases (P < 0.05) in the levels of malondialdehyde (MDA) in T.B infected cattle, and contact group compared with negative group, In contrast, there was a significant reduction (P < 0.05) in the level of R.GSH ,catalase, vit A and vit C. Biochemical analysis of positive cases and their contact revealed significant increase in globulin content and decrease in albumin content, resulting in altered A/G ratio Serum enzymes analysis revealed significant (P<0.05) increase in alkaline phosphatase activities (ALP) aminotransferases (AST, ALT activities) creatinine phosphokinase (CPK), gamma. glutamyl transferase (GGT), and lactate dehydrogenase (LDH) in infected and contact cattle in comparison with negative group.