Paratuberculosis caprinauna revisión con especial énfasis en su interferencia con el diagnóstico de la tuberculosis

Abstract

The paratuberculosis, caused by Mycobacterium avium paratuberculosis, affects domestic and wild ruminants, it is widely distributed, has a fecal-oral spread, a chronic development and causes serious economic losses. The immune response changes during the infection, and with it the stage of disease, the histological injury and the response to diagnostic tests. Paratuberculosis produce lesions mainly in the terminal ileum (lymphangiectasia, intestinal villi atrophy, granulomatous enteritis) that enable post-mortem identification of the disease and its differentiation from caprine tuberculosis. The clinical picture consists of a progressive thinning and some cases of diarrhea, and appears between 2 and 4 years old sporadically. The diagnosis of paratuberculosis is done by the detection of the cellular immune response by intradermal-reaction (with avian PPD or johnine) and gamma interferon (IFN-γ). There is no effective treatment, and control is performed by management and vaccination. The paratuberculosis interference in the diagnosis of caprine tuberculosis consists in a decreased sensitivity of cell-immunity based tests, which affects more comparative intradermal-reaction. Therefore, it is advisable to combine as diagnostic tests for tuberculosis, in paratuberculosis infected flocks, the single intradermal-reaction and the IFN-γ test, using as complementary test the ELISA based on MPB-70 antigen, in paratuberculosis infected flocks. About the interference of vaccination against paratuberculosis, in caprine tuberculosis diagnosis, the currently used vaccines (attenuated and inactivated) produce a similar immune response to the natural infection, and there is a long-term interference (20 months) with the tuberculosis diagnosis. This interference can be avoided by using DIVA vaccines, with specific antigens of M. tuberculosiscomplex, which would facilitate the eradication of tuberculosis.