Yaws, an infectious disease caused by Treponema pallidum subspecies pertenue, affects mainly children in poor rural communities in tropical countries. This bacterium is transmitted by direct skin-to-skin, nonsexual contact and causes a chronic, relapsing disease that is characterized by highly contagious primary and secondary cutaneous lesions and by noncontagious tertiary destructive lesions of the bones. Cases are reported currently in 12 countries in Africa, Asia, and the western Pacific region, and 42 million people are estimated to be at risk for yaws.
