The avian mycobacteria have been identified first in relation to their
virulence for hens. But this property was not definitely to correlate
with serovars. Furthermore, this heterogenicity was to confirm on mol
ecular level. Therefore it was necessary to introduce a M.avium comple
x beside true M.avium. M.avium has special relevance to AIDS patients.
This fact shows that the reasons for infections by these facultativel
y pathogenic mycobacteria are more complicated as accepted.