Diagnosis and epidemiology of bovine tuberculosis using molecular biological approaches.

Conventional methods for diagnosis and epidemiological studies of bovine tuberculosis and other mycobacterial diseases are far from ideal. In the last twelve years, molecular biology has provided new approaches which have enabled detailed studies to be made of the molecular characteristics of Mycobacterium bovis, the causative organism of bovine tuberculosis. These characteristics have been investigated for their potential use in diagnosis and epidemiological studies. Restriction fragment analysis of genomic DNA from isolates of M. bovis has provided a highly discriminatory typing system which has been used extensively for epidemiological studies. DNA elements in M. bovis have been investigated for their potential use in diagnostic assays based on the polymerase chain reaction. Individual antigens of M. bovis and their reactive epitopes have been identified and investigated for their usefulness in both serological and T cell assays of animal infection. Serological assays have proven disappointing and the full potential of T cell assays has yet to be determined. Currently, T cell assays based on recombinant antigens have not been as sensitive as those based on natural antigens.