USE OF VARIOUS GENETIC-MARKERS IN DIFFERENTIATION OF MYCOBACTERIUM-BOVIS STRAINS FROM ANIMALS AND HUMANS AND FOR STUDYING EPIDEMIOLOGY OF BOVINE TUBERCULOSIS

One hundred fifty-three Mycobacterium bovis strains from cattle, vario us animal species from zoos and wild parks, and humans were analyzed f or three different genetic markers for use in the epidemiology of bovi ne tuberculosis. M. bovis strains isolated from cattle were found to c arry a single IS6110 element, whereas the majority of strains from oth er animals such as antelopes, monkeys, and seals harbored multiple IS6 110 elements, suggesting that the reservoirs in cattle and wild animal s are separated. Because the single IS6110 element in cattle strains i s located at the same chromosomal position, strain differentiation by insertion sequence fingerprinting was hampered. Therefore, we investig ated the usefulness of the direct repeat and polymorphic GC-rich repea t elements for strain differentiation. Both markers allowed sufficient strain discrimination for epidemiological purposes. Evidence is prese nted that in Argentina, most human M. bovis infections are due to tran smission from cattle, whereas M. bovis infections among humans in the Netherlands are mainly contracted from animals other than cattle. Vari ous outbreaks of M. bovis among animals and humans are described, incl uding a small one which likely involved transmission from human to hum an.