Comparison of DNA probe test and cultivation methods for detection of Mycobacterium avium subsp paratuberculosis in caprine and ovine faeces

OBJECTIVE: To compare a DNA probe test with two cultivation methods for the detection of Mycobacterium avium subsp paratuberculosis in goat and sheep faeces. DESIGN: Comparison of the results of the three methods with histological examination as the reference standard. PROCEDURE: Faecal specimens were obtained from goats and sheep originating from flocks known to be affected with paratuberculosis and tested for Mycobacterium avium subsp paratuberculosis with a DNA probe test and two cultivation methods (old conventional culture and new double incubation method in Herrold's and Lowenstein-Jensen medium). RESULTS: In goats, the sensitivity of the various tests were for the DNA probe test 17.2%, for the double incubation culture method 25.4% and for the old conventional culture method 22.8% using the histopathological results as reference. In sheep the sensitivity of the various tests were for the DNA probe test 13.2%, for the double incubation culture method 8.8% and for the old conventional culture method 5.9% using the histopathological results as reference. The specificity of the above tests was 100% in goats and sheep and the specificity of the double incubation culture method in goats was 91%. CONCLUSIONS: The DNA probe test is a rapid and specific test that could be used in a control program if the sensitivity of the test were improved and possibly in combination with another test.