Skin lesions on a limb caused by Yaws, a chronic granulomatous disease caused by the spirochaete bacteria, Treponema pertenue. T. pertenue is morphologically identical to T. pallidum, the cause of venereal & non-venereal syphilis. Yaws occurs in children living in rural, tropical areas. Transmission is by direct contact with an infectious lesion or lesion exudate and is enhanced by a crowded environment with poor sanitation and personal hygiene. The course of yaws progresses in stages, in a similar way to venereal syphilis. Late yaws may involve deep ulceration with disfiguring tissue destruction.