The distribution of species of mycobacteria other than tubercle bacilli which cause lung disease and those isolated from sputum specimens, including the strains that cause disease and casual isolates, are different in various countries and in different area in the same countries. In Japan, the disease occur more frequently in the Pacific ocean coast (South coast) of the Honshu island and relatively rare in North Japan. Disease due to
M. kansasii occurs frequently in the Tokyo area. Geographic difference in the occurrence of the disease is reported also in the United States of America, Australia and West Germany.
The difference in the species of the mycobacteria that cause the disease and those isolated from sputa is considered to be related to the geographical difference of the ecology of mycobac teria.
Generally speaking, disease due to
M. kansasii occupies more than one half of the disease due to all mycobacteria other than tubercle bacilli in the United States of America and in Europe. In contrast to the above, disease due to
M. intracellulare occupies 75 to 90% of the disease, and the disease due to
M. kansasii remains at the level of a few per cent in Japan and Australia.
Moreover, disease due to M. xenopi occurs in the former areas, whereas the disease has not been seen up to now in the latter areas.
In the United States, the proportion of the strains that show Avium serotype is 25% among the
M. aviurnintracellulare strains that caused lung disease, whereas the rate remains only a few per cent in Japan.
Difference in some biological characteristics are also observed between the strains isolated in Japan and the strains isolated in Rhodesia. The majority of the Japan isolates grow at 45°C, whereas the majority of the Rhodesian isolates do not grow at this temperature.
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