Bovine tuberculosis has long been detected by skin testing with purified protein derivatives (PPD-H) tuberculin. In the present study, skin test based on specific immunodominant epitope (ESAT6-P) of Mycobacterium bovis and enzyme liked immunoassay (ELISA) are compared with "gold standard" culture method for their efficacy in detecting bovine tuberculosis in naturally infected cattle. Investigation demonstrated that the kinetic of the skin test response different for two reagents; (PPD-H) tuberculin showed maximal response at 72 hrs post injection, but the response to ESAT6-P often peaked later at 96 hrs post injection. ESAT 6-P showed to have promising diagnostic potenial (sensitivity, 82%; specificity, 100%; optimal cut off, 3 mm), compared with PPD-H (sensitivity, 82%; specificity, 87%; optimal cut off, 4 mm). On the other hand, ELISA technique declared that sensitivity of ELISA showed (76% and 70%) and the specificity of (100% and 87%) for ESAT6-P and PPD-H, respectively. The present results indicate great potential for skin test and ELISA based on specific antigens for accurate in vivo diagnosis of bovine tuberculosis. |
