Comparative Studies On Diagnostic Tests Of Bovine Tuberculosis And Isolation And Identification Of Mycobacterium Bovis

Bovine tuberculosis is a zoonotic disease that is seriously detrimental to the dairy industry and human health.Controlling or eradicating bovine tuberculosis is a strategy for eradicating human tuberculosis,while fast and efficient diagnosis of bovine tuberculosis is crucial.Infection of cattle with Mycobacterium bovis(M.bovis) is usually chronic and can remain subclinical for a long period.Importantly,infected cattle can become infectious long before they exhibit any obvious clinical signs or lesions typical of tuberculosis detectable even with the most careful veterinary examination.Thus,effective ante mortem surveillance for bovine tuberculosis must primarily rely on the detection of infected cattle at an early stage by the use of sensitive immunodiagnostic tests.Here,three methods for diagnosis of bovine tuberculosis were compared,and 2 strains of Mycobacterium bovis were isolated and identified as following:Tuberculin skin test and comparative skin test was performed by using bovine purified protein derivertive(PPD) and avium PPD in the meantime.Meanwhile,after three days,collecting Heparin anti-hemoglutination whole blood,using BOVIGAMTM test kit to diagnose the supernatants of whole blood stimulated by diversified PPD.The experimental results showed that in the 200 cows,SICTT, traditional TST and IFN-γtest positive cows were 91,98,85,respectively. Coincidence rates of IFN-γ,test and TST,IFN-γtest and SICTT were 92.86%,95.79%, respectively.In three cows,traditional intradermal tuberculin skin test positive but SICTT negative,it indicated that Mycobacterium avian interfereed with the bovine TST in certain extent.Two cattle that were positive in tuberculin skin test,comparative skin test and IFN-γtest in the meantime were selected and anatomized.Bacterium was isolated from of lungs and lymph nodes tissues with histological lesions respectively.Two M.bovis strains were isolated by culturing for 5-15 days.The bacilli were transported to amplifying medium,and it is positive in Ziehl Neelsen stain.DNA of M.tuberculosis, M.bovis and 2 strains of isolated bacilli were extracted by using DNeasy Tissue Handbook kit.DNA of M.tuberculosis,M.bovis were used as templates and typing PCR test was developed by using primers of 16S RNA,Rv0577,IS1561,Rv1510 (RD4),Rv1970(RD7),Rv3877/8(RD1) and Rv3120(RD12).Two strain of isolated mycobacterium were amplified by using tying PCR test.it is conformed that 2 strain of mycobacterium were M.bovis.Those two strains were named as M.bovis—Changping07101 and M.bovis—Changping07102...