Treponemal infections occurring in humans comprise venereal syphilis and the non-venereal endemic treponematoses. The non-venereal endemic treponematoses are yaws, pinta, and endemic syphilis. Yaws is a chronic, relapsing disease predominantly affecting children living in certain tropical regions. Clinical manifestations of yaws are divided into various stages. Early stage skin lesions are infectious and can persist for weeks or months. Involvement of the bones of the upper and lower limbs and the fingers and toes can cause pain and digital swelling. After the early stage lesions subside due to the host immune response, the patient enters a latent stage that can be lifelong.
