Ugotavljanje povezave med bakterijo Mycobacterium avium subsp. paratuberculosis pri živalih in Crohnovo boleznijo pri ljudeh (Slovene)

Development and optimization of new DNA extraction procedures and development of new highly efficient DNA amplification using real time PCR represent an important contribution to the development of paratuberculosis diagnostics on international level as there is still no reliable method for diagnostics of paratuberculosis comercially available. Comparison of serum ELISA, milk ELISA, culture method and molecular tests showed markedly (up to 50-times) lower sensitivity of serological tests compared to culture and molecular methods used in herds with clinical paratuberculosis. In herds with latent paratuberculosis, milk and serum ELISA gave discrepant results and have most probably only 90% specificity. These findings are important on international level as up to date comparison results are contadictive and frequently based on out-of-date methods. The results of the study on CD patients indicate a link between the presence of Map in the intestines and blood and CD. However, to demonstrate the causative link further studies are needed. Detection of polymorphisms which determine genetic predisposition of CD patients in Slovenia represents an important piece of global knowledge on the etiology of CD.

In the scope of this project it was demonstrated that large herds of dairy cattle are infected with Map to a large extent. This calls for immediate preparation of control measures on the state level as paratuberculosis may endanger the economy of infected herds which represent an important share of milk production in Slovenia. In heavily infected herds, the measures were implemented already during the project to partially limit the losses due to paratuberculosis and to preserve milk production in these herds. Improved diagnostics of paratuberculosis will contribute to easier and faster detection of infected animals/herds and to more efficient suppression of the disease. Efficient diagnostics (which is nowadays mostly unsatisfactory) is a prerequisite to motivate the cattle breeders for implementation of the control measures as these will bring satisfactory effects on a long term only. Knowledge on shedding of mycobacteria and their survival in the environment and in food will help us to detect critical points for spread of the infection and potential danger of the food for public health. On this basis, the measures for limiting the spread of disease and providing safer food may be proposed.