Mycobacterium Ulcerans - Epidemiology and Transmission

Epidemiology and Transmission

The source(s) of M. ulcerans in nature is becoming clearer from epidemiologic data and from molecular biologic findings. Because all major endemic foci are in wetlands of tropical or subtropical countries, environmental factors must play an essential role in the survival of the etiologic agent. Koalas and possums are naturally infected animals in Australia. The disease is rarely transmitted from patient to patient. Trauma is probably the most frequent means by which M. ulcerans is introduced into the skin from surface contamination. Individuals of all ages are affected, but the highest frequencies of infection are in children under 15 years of age (Debacker et al. accepted for publication).

The largest known concentrations of patients are in Africa: Congo and Cameroon in Central Africa, Côte d'Ivoire, Ghana and Benin in West Africa. Some Southeast Asian countries (Papua New Guinea) and Australia have major foci, and there have been a few patients reported from South America (French Guyana and Surinam) and Mexico. Focal outbreaks have followed flooding, human migrations, and man-made topographic modifications such as dams and resorts. Deforestation and increased basic agricultural activities may significantly contribute to the recent marked increases in incidences of M. ulcerans infections, especially in West Africa, where the disease is rapidly emerging.