Prevalence of bovine infection with mycobacterium bovis some Egyptian Governorates

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

Evaluation of sensitivity and specificity of bovine Gamma-Interferon In-Vitro Assay for Diagnosis of tuberculosis in buffaloes

The sensitivity and specificity of the Bovine Gamma Interferon [IFN-lambda] in-vitro assay [BOVI-GAM] in the diagnosis of bovine tuberculousis in buffaloes as compared to the single intradermal cervical tuberculin test [SICT] and cultural isolation of Mycobacterium bovis were investigated. Thirty buffaloes from a dairy farm, in which tuberculin positive animals had been previously diagnosed, were tested. In the SICT test examined buffaloes 36.7% were positive and 23.3% were doubtful as compared with 53.3% positive and 16.7% doubtful results using the IFN- lambda assay. Two animals were positive to avian tuberculin in the IFN- lambda assay. The prevalence rate reached 60% and 70% using the SICT test and the IFN- lambda assay respectively. The sensitivity of the SICT and the IFN- lambda assay as compared with the cultural isolation of M. bovis were 75% and 95%, respectively, while the specificity were 70% and 80%, respectively. M. bovis was isolated from five buffaloes that were negative to SICT and one buffalo that was negative to the IFN- lambda assay. In conclusion, the present study demonstrated that the IFN- lambda assay is a practical, more sensitive and specific in-vitro diagnostic test than the conventional tuberculin test for detection of bovine tuberculosis in buffaloes

Purification of 38KDa antigen for diagnosis of tuberculosis in buffaloes

The 38 kDa antigen of Mycobacteriurn tuberculosis strain H37/Rv was prepared und purified from the unheated culture filtrate by alcohol fractionation after being precipitated with ammonium sulphate. The prepared antigen was evaluated in comparison with bovine tuberculin by skin sensitivity test and ELISA in guinea pigs experimentally infected with typical and atypical mycobacteria. Results indicated the ability of 38 kDa antigen to differentiate between guinea pigs infected with both types of mycobacteria. Also, the antigen was evaluated in comparison with bovine PPD using ELISA for serum samples taken from tuberculin positive and negative buffaloes. The antigen was able to distinguish infection of pathogenic potential forms from cross-reaction sensitization by environmental mycobacteria at serum dilution of 1/80. Specificity of the 38 kDa antigen was 88.9% versus to 66.7% for bovine PPD. Therefore, 38 kDa antigen is strongly suggested for serological diagnosis of bovine tuberculosis