Pathology, immunohistochemistry and molecular study of cattle screened by comparative tuberculin test for diagnosis latent form of Johne's disease.

Abstract Mycobacterium avium subsp. paratuberculosis causes Johne’s disease in cattle and other ruminants. It is one of the most widespread in terms of prevalence and one of the most important diseases in the livestock industry in terms of economic importance. In the latent form of the disease, animals can act as carriers. The main purpose of this study was to evaluate avian tuberculin in a single intradermal comparative tuberculin test (SICTT), histopathology, immunohistochemistry, and molecular methods for diagnosis of infected cows with the latent form of the disease. Twenty-three asymptomatic cows and without post-mortem signs of the disease were selected using the single intradermal comparative tuberculin test and were tested. In this study, avian tuberculin in SICTT was able to in diagnosing the latent form of the disease. The results confirm immunohistochemistry and real-time PCR as a sensitive and reliable diagnostic complementary approach for detecting latent forms of Paratuberculosis.