Diagnosis of Bovine Tuberculosis by PPD-ELISA and Sonication-ELISA

ABST RACT Mycobacterium bovis (M. bovis) infection in cattle remains a major zoonotic and economic problem in many countries. In addition, M. bovis is an important pathogen of both man and animals. The standard diagnostic test for this disease is the intradermal tuberculin test, one of the oldest immunological tests still in widespread use. However, this test can lack both sensitivity and specificity. Serological tests such as ELISA (Enzyme Linked Immunosorbent Assay) have been suggested as an alternative method for the diagnosis of tuberculosis. In the present study, two serum ELISA’s, performed for the detection of M. bovis-specific antibodies, were evaluated against the culture of tissue samples from 135 slaughtered dairy cows, which were intradermal tuberculin-test-positive. ELISA plates were coated with Bovine Purified Protein Derivative (PPD B) and M. bovis-sonication antigen. Samples were taken from the bronchial (BLN), mesenteric (MLN) and prescapular (PLN) lymph nodes and tubercules (TB) of slaughtered cattle. Tissue samples were cultured in Lowenstein-Jensen medium. Blood samples, which were collected from the tuberculin-testpositive animals before slaughter, were tested by PPD B-ELISA (PPD-ELISA) and M. bovis sonicationELISA (sonication-ELISA). Mycobacterium spp. was isolated from 77 out of 135 cattle. Out of 135 cattle, 62 (45.9%) and 43 (31.8%) were determined to be positive for PPD-ELISA and sonication-ELISA, respectively. Using culture-positive animals as a gold standard, the sensitivity and specificity of these two methods were detected as 48.2%-55.2% and 31.2%-44.5%, respectively.