(pian, framboesia) n. a tropical infectious disease caused by the spirochaete Treponema pertenue in the skin and its underlying tissues. Yaws occurs chiefly in conditions of poor hygiene. It is transmitted by direct contact with infected persons and their clothing and possibly also by flies of the genus Hippelates. The spirochaetes enter through abrasions on the skin. Initial symptoms include fever, pains, and itching, followed by the appearance of small tumours, each covered by a yellow crust of dried serum, on the hands, face, legs, and feet. These tumours may deteriorate into deep ulcers. The final stage of yaws, which may appear after an interval of several years, involves destructive and deforming lesions of the skin, bones, and periosteum (see also gangosa; goundou). Yaws, which commonly affects children, is prevalent in hot humid lowlands of equatorial Africa, tropical America, the Far East, and the West Indies. It responds well to antibiotics.... yaws
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