An infectious disease that tends to be found throughout poorer subtropical and tropical areas of the world. Yaws is caused by a spirochaete (a spiral-shaped bacterium), and it spreads principally in conditions of poor hygiene. The infection is almost always acquired in childhood, and it mainly affects the skin and bones. The bacteria enter the body through abrasions in the skin. Three or 4 weeks after infection, an itchy, raspberry-like growth appears at the site of infection, sometimes preceded by fever and pains. Scratching spreads the infection and causes more growths to develop elsewhere on the skin. Without treatment, the growths heal slowly over the course of about 6 months, but recurrence is common. In about 10 per cent of untreated cases, widespread tissue loss eventually occurs. This may eventually lead to gross destruction of the skin, bones, and joints of the legs, nose, palate and upper jaw. Yaws can be cured by a single large dose of a penicillin drug given as an injection into muscle.


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