A qualitative immunoassay as complementary test with tuberculin skin test for detection of tuberculosis in dairy cattle

Bovine tuberculosis, caused by Mycobacterium bovis, is a zoonotic disease causing approximately 6% of total human deaths.  Its economic losses are not only a reduction of 10-20% in milk production and weight, but also infertility and condemnation of meat. Many serological tests are applied for detection of tuberculosis. ELISA test has the highest sensitivity and specificity than the other serological tests for the diagnosis of tuberculosis. Several forms of new technology were brought into the diagnostic approach to mycobacterial infection. The aim of this work was to detect bovine tuberculosis by application of different serological tests. Tuberculin skin test was applied on 2650 cattle, only 63(2.4%) were positive. Forty eight (76.2%) of the slaughtered positive animals showed visible lesions (VL) while the other 15 (23.8%) had non-visible lesions (NVL). The bacteriological examination of the 63 samples revealed isolation of M. bovis from 47 processed samples (74.6%). The results of the immunoassay test have detected 27 out of the tuberculin positive cattle, while the ELISA has detected 34 out of the positive reactor cattle. It was concluded that immunoassay and ELISA tests act as complementary tests for tuberculin skin test especially in anergic cattle.