![]() | Only 14 pages are availabe for public view |
Abstract Bovine tuberculosis, caused by infection with Mycobacterium bovis, continues to be a major economic problem in several countries and constitutes a serious public health risk in a number of developing countries. The principal aim for control of bovine tuberculosis is to eliminate the risk of infecting humans, and in developed countries, the aim of vaccination of cattle should be ideally to prevent the establishment of infection. This is a difficult challenge as the aim of vaccination programmes against most human and animal pathogens is to prevent clinical disease, rather than infection. Since vaccination of cattle is unlikely to be totally effective, ancillary diagnostic testing of cattle would have to be undertaken in association with vaccination and vaccinated animals should not react in the tuberculin or alternative diagnostic tests. in our study we aimed to evaluate the vaccine of bovine tuberculosis (BCG) and its ability to prevent confusing between vaccinated animals and infected animals at using of bovine tuberculosis diagnostic tests. In our study we tested 900 animals (420 cattle and 480 buffaloes) from different localities at Minufiya and Gharbia governorates .By application of tuberculin test on these animals, it showed that 9 cattle (2.14 %) and 27 buffaloes (5.62 %) were positive tuberculin reactors while the remaining animals were negative. from these negative reactor animals we vaccinated 6 animals with Bacilli Calmette Guerin (BCG), and retesting of these vaccinated animals with tuberculin test has been done after 8 weeks and gave negative tuberculin reaction .Positive tuberculin tested animals were slaughtered and examined to determine the post mortem lesions which were 8 (88.9%) out of 9 cattles and 4(14.8%) out of 27 buffaloes showed visible lesions. Summary 98 The lymph nodes and tissue samples were collected from the positive tuberculin (9) cattles and (27) buffaloes. On histopathology on the positive reactor tissues by Z.N. staining of acid fast bacilli, we found that all positive cattles 9(100%) gave positive when stained with Z.N. While 5 (18.5%) tissues gave positive with Z.N from 27 positive tuberculin buffaloes. and 17(62.96%) tissues gave positive with H&E. On the bacteriological examination of the tuberculin positive cattle tissues which were (8 with VL and 1 with NVL), 8 (88.9%) acid fast bacilli were isolated. The total 8 tissues showed visible lesions grew on Lowenstein-Jensen medium with sodium pyruvate and all the 8 isolates (100%) gave positive with ZN stain. In buffaloes, the total acid fast bacilli isolated from 27 tuberculin positive buffaloes were 17 (62.9%) .9 colonies grew on L.J with glycerol and 8 grew on L.J with sodium pyrovate . With examination by ZN stain, all 17 isolates (100%) gave positive results After using PCR and LCD hybridization array indicated that higher prevalence of Mycobacterium tuberculosis complex in all cattle cases(9) and that confirmed by the genotyping using MIRU technique that detected M.bovis typical types on the contrary expressed by buffalo cases especially after the results of PCR and LCD hybridization array that gave Mycobacterium other than tuberculosis (MOTT) and other than the typable species in the list of the array test this means atypical types . We used ELISA with 4 types of antigens (PPD, ESAT-6, CFP10, MBP70) to discriminate between negative, infected and vaccinated animals .This test showed that all positive tuberculin reactor animals gave. |