This is a photo of a smear positive for bacterium called Mycobacterium ulcerans, the cause of Burulu ulcer, a tough nut to crack thus far. Central and West Africa are the worst hit. The only treatment is excision and closure, which can be disconfiguring, or amputation. Sometimes the ulcer will heal itself, but usually does so in a disconfiguring way. Antibiotics have not yet worked.
Treatment is expensive, and long.
No race is immune. It is not communicable from patient to patient. Environmental factors appear to play a role. Ghana's Noguchi Memorial Institute for Medical Research is playing a lead research role with the US Centers for Disease Control. April 29, 2001.