Seasonal distribution of mycobacterial skin ulcers.

Chronic necrotizing skin ulcers caused by Mycobacterium ulcerans are a common and serious disorder in certain parts of the tropics. This infection was first described in Australia, but most of the reported cases have come from Uganda (where the disease is known as Buruli ulcer) and from the Congo. The disease is also known to occur in Nigeria, Ghana, Mexico, and New Guinea. The results of epidemiological studies in Uganda strongly suggest that the disease is not usually transmitted from one person to another, and that there is a nonhuman source of Myco. ulcerans infection (Uganda Buruli Group, 1971). This source remains unknown, but there is some evidence in support of a recent hypothesis that Myco. ulcerans occurs on vegetation growing on poorly drained soil, and that Buruli disease is contracted by contact with this vegetation and subsequent penetration of the organism through small scratches or other traumatic lesions in the skin (Barker, 1971).