- Adult Skin Problems Slideshow
- Quiz: Is Ringworm Contagious?
- Gallery of Skin Problems Pictures
- Patient Comments: Yaws - Symptoms
- Yaws facts
- What is yaws? What are symptoms of yaws?
- What causes yaws?
- What are risk factors for yaws?
- How does yaws begin and spread?
- Why is this disease called yaws?
- What are developmental stages in the course of yaws?
- What types of specialists treat yaws?
- How do health-care professionals diagnose yaws?
- What is the treatment for yaws?
- Why is yaws a serious problem?
- What is the prognosis of yaws?
- Is it possible to prevent yaws?
What causes yaws?
Yaws is caused by a particular bacterium called a spirochete (a spiral-shaped type of bacteria). The bacterium is scientifically referred to as Treponema pertenue. This organism is considered by some investigators to be a subspecies of T. pallidum, the organism that causes syphilis (a systemic sexually-transmitted disease). Other investigators consider it to be a closely related but separate species of Treponema. T. carateum, the cause of pinta (a skin infection with bluish-black spots), is also closely related to T. pertenue. The history of yaws is unclear; the first possible mention of the disease is considered to be in the Old Testament. D. Bruce and D. Nabarro discovered the spirochete causing yaws (T. pertenue) in 1905.
What are risk factors for yaws?
The main risk factor for yaws is direct contact with another person (nonsexual contact) that has yaws lesions on the skin or being a member of the community where yaws infections are endemic. The bacteria that cause yaws only infect humans if there is a break (cut) or abrasion of the skin. Consequently, having a break (cut) or abrasion of the skin while in a geographic area where yaws is endemic is another risk factor for yaws. Poor hygiene and crowded conditions are also risk factors.
How does yaws begin and spread?
Yaws begins when T. pertenue penetrates the skin at a site where skin was scraped, cut, or otherwise compromised. In most cases, T. pertenue is transmitted from person to person. At the entrance site, a painless small lesion, or bump, arises within two to eight weeks and grows. The initial lesion is referred to as the mother yaw. The lymph nodes in the area of the mother yaw are often swollen (regional lymphadenopathy). When the mother yaw heals, a light-colored scar remains.