Diagnosis is difficult, particularly in the case of subclinical disease as there is no single test that will detect all stages of the disease. The most commonly used diagnostic test is the ELISA which detects antibodies to ''M. paratuberculosis'' in clinically affected animals. | Diagnosis is difficult, particularly in the case of subclinical disease as there is no single test that will detect all stages of the disease. The most commonly used diagnostic test is the ELISA which detects antibodies to ''M. paratuberculosis'' in clinically affected animals. |