DEMOGRAPHIC STUDY OF DISEASE DUE TO MYCOBACTERIUM-KANSASII OR M-INTRACELLULARE-AVIUM IN TEXAS

The number of patients reported to have disease due to Mycobacterium kansasii or M intracellulare-avium has increase in Texas from January 1967 to December 1976, in contrast to a decrease in tuberculosis. Presented is an analysis of 1,409 patients infected with M kansasii and 706 patients infected with M intracellulare-avium. The former group clustered in urban areas with more than twice the incidence compared to nonurban areas (P < 0.001). The latter group was more diffusely distributed with approximately twice the incidence in nonurban areas compared to urban areas (P < 0.001). The average age of the group infected with M kansasii was 50 years and of the group infected with M intracellulare-avium 58 years. In patients infected with M kansasii only, the average age was significantly higher for men than women. There was a male predominance in both groups, ie, 3:1 in M kansasii and 2:1 in M intracellulare-avium. Persons with Spanish surnames had a low incidence of disease due to M kansasii. No other racial or ethnic association was noted. The various factors involved in determining the atypical mycobacterial diseases are discussed.