Yaws is a chronic infectious disease caused by the bacterium Treponema pallidum pertenue. It primarily affects the skin, bones, and joints, leading to painful sores and lesions. The disease is most common in tropical regions and is transmitted through direct contact with an infected person's skin lesions. The symptoms of yaws typically begin with a single sore, which can develop into multiple lesions over time. If left untreated, yaws can cause severe complications, including deformities and disability. Treatment usually involves antibiotics, particularly benzathine penicillin, which is effective in curing the infection and preventing further spread.