Mycobacterial infections of ruminants in the EC are common, resulting in high economic and social penalties. The ineffectiveness of existing methods for the diagnosis and control of these mycobacterial infections, especially paratuberculosis, have been highlighted by recent meetings of the EC. These conferences have advised prompt action to combat the spread and high prevalence of these infections.
The project has two main objectives. First, to improve the sensitivity and specificity of diagnostic procedures for the detection and discrimination of mycobacterial infections of domestic ruminants. Second, to demonstrate that application of these improved diagnostic tests will promote control measures.
The project was set up to improve the sensitivity and specificity of diagnostic procedures for the detection and discrimination of mycobacterial infections of domestic ruminants with a view to implementation of control measures. An inexpensive and rapid polymerase chain reaction (PCR) procedure has been developed to discriminate between different mycobacteria. Variation in primers allows general detection of all mycobacteria or specifically Ma paratuberculosis or Ma silvaticum. A number of genes (S1, S2, S4/58, S5) encoding immunogenic proteins have been identified. Two of these (S4/58 and S5) have been expressed as fusion proteins. Two other proteins have been identified and purified (a 30 kDa alpha antigen and a 40 kDa protein). The latter appears to be present only in Ma silvaticum. Several monoclonal antibodies have been produced to S4, S5 and the 40 kDa protein. A gamma-interferon enzyme linked immunosorbent assay (ELISA) has been adapted to detect cell mediated immune responses to mycobacteria in sheep. The test appears to be highly specific in identifying experimentally infected animals when used in conjunction with species specific proteins, such as the 40 kDa protein. ELISAs utilizing the S4 and S5 recombinant proteins and monoclonal antibodies are being developed. Sheep, goats and deer have been infected experimentally with Ma paratuberculosis or Ma silvaticum. Samples are being collected for retrospective analysis and appraisal of the new tests described above.
The project will identify specific immunogens, genes and monoclonal antibodies, which will be incorporated in improved diagnostic procedures to detect infected animals and environmental contamination. The latter tests and protocols will be assessed not only in experimentally- infected deer, sheep and goats, but also in small, local field trials.