Epidemiology of Mycobacterium ulcerans infection (buruli ulcer) at Kinyara, Uganda

Abstract
The epidemiology of lesions due to Mycobacterium ulcerans was studied in an almost closed community of 2500 Rwandan refugees living near the Nile in central Uganda over a period of years during which 220 of them showed the disease. The incidence was greatest in children aged 5–14 years, in those living nearer to the Nile, and during the months September to November. In adults it was greater in women than in men. The geographical gradient in incidence was more apparent among women, whereas temporal variation mainly affected the men. Direct contact with the Nile was not necessary for transmission. The disease gave no evidence of spread from person to person and the incidence fell to zero when the people moved to a new locality. The incubation period was usually under 3 months. Lesions were usually single; they occurred on any part of the body in children but were largely confined to the limbs in adults. In men lesions were almost restricted to the lower legs whereas in women the arms were also often affected. Hypotheses of transmission are discussed in relation to these observations.