Postulated epidemiology of Mycobacterium ulcerans infection.

Mycobacterium ulcerans infection occurs in closely defined areas throughout the world, mostly in the tropics. Whenever it occurs there is a relationship with rain forest and this relationship is apparent in Gippsland, Australia which is not tropical but which contains isolated pockets of relict warm temperate rain forest. Human infection follows rain forest disturbance; it is postulated that the mycobacterium is carried into draining lacustrine systems where it multiplies over a period of months or years and is then disseminated in aerosol from to re-infect its ancestral home and incidentally to infect man.