or frambesia
Contagious tropical disease, caused by a variant of the spirochete that causes syphilis .
Yaws spreads mainly by discharge from skin sores, not sexual activity. It is common in children, who usually become immune. In the first stage, a skin sore starts as a wartlike thickening, cracks open, leaks fluid, and bleeds easily. A month or more later, multiple sores erupt. The third stage (much rarer than in syphilis) involves destruction of skin, mucous membranes, and bones. Penicillin cures early-stage yaws. Prevention requires isolation and prompt treatment and personal and group hygiene.