Submitted to: Proceedings of the Mexican Animal Health Council
Publication Type: Proceedings
Publication Acceptance Date: November 15, 1995
Publication Date: N/A
Technical Abstract: Johne's disease (paratuberculosis) in cattle is characterized by a chronic granulomatous enteritis caused by the acid-fast bacterium, Mycobacterium paratuberculosis. Diagnosis of subclinical M. paratuberculosis infection present a major problem in control of this disease. Although many diagnostic tests have been developed for paratuberculosis, a detection assay that is efficient, specific, and sensitive is currently lacking. Cultivation of M. paratuberculosis from fecal or tissue specimens is the most definitive and frequently used diagnostic test for Johne's. The most common immunologic tests used for diagnosis of paratuberculosis are the agar gel immunodiffusion assay, ELISA, and complement-fixation test. Nucleic acid probes with high specificity have recently been developed for detection of paratuberculosis infection, however, they have a low detection sensitivity. The most recent test for paratuberculosis is a cell-mediated immune assay based upon the release of interferon by cells stimulated in culture with mycobacterial antigens. The advantages of this test are that it is capable of detecting subclinically infected animals in a herd since cell-mediated immunity occurs in the early stages of host responses to mycobacterial pathogens. There is an imperative need for improved diagnostic tests for the detection of paratuberculosis in cattle.