Paratuberculosis:: which diagnostic tests to use?

The main direct diagnostic tests for M. paratuberculosis are coprobacterioscopy and faecal culture, but provision of results is slow. PCR and mesenteric lymph node biopsy may also be used. There are various indirect immunological methods. The main tests are allergic and not highly specific such as the complement fixation test, indirect immunofluorescence, gel precipitation test and ELISA, the most sensitive technique. None of these tests alone are sufficient to diagnose paratuberculosis. The choice of test depends on the required objective: individual screening or herd testing to confirm suspected clinical cases, to estimate the level of infection or to institute a control programme.