A chronic infection caused by the bacteria Treponema pallidum, subspecies pertenue which primarily affects the skin and bones.
Causes, incidence, and risk factors
Yaws is an infection caused by the spiral-shaped bacterium (spirochete) called Treponema pertenue that is closely related to the organism that causes syphilis -- yet is not sexually transmitted. Yaws is primarily an illness involving children in rural, warm, tropical areas -- primarily Caribbean Islands, Latin America, west Africa, India and southeast Asia. Yaws is transmitted by direct contact with skin lesions of infected people -- and not by sexual contact. Approximately 2 to 4 weeks after infection, the child develops a sore "mother yaw" where the organism entered the skin. The sore appears as "raspberry-like" growth or group of papules at the site of infection and is usually painless. These lesions may persist for months. Additional satellite lesions may appear shortly before or after healing of the mother yaw. Children may also develop inflammation of the bones and fingers. The final stage occurs in up to 20% of untreated individuals and involves destructive lesions of the skin and bones which can lead to severe disfigurement and disability.
Signs and tests
The diagnosis can be confirmed by examination of a sample from a skin lesion under special type of microscope (darkfield examination). There is no specific blood test for yaws, yet since it is closely related to the bacterium which cases syphilis, the blood tests for syphilis may be positive in yaws as well.
Treatment
The mainstay of treatment is a single dose of penicillin G. Relapse is rare.
Expectations (prognosis)
If appropriately treated in its early stages, yaws is highly curable. Skin lesions may take several months to heal. If treated in its late stage, significant disfigurement may already be present and may not be fully reversible.
Complications
Yaws can cause be disfiguring and disabling as it may cause gross destruction of the skin and bones. It can also cause deformities of the legs, nose, palate, and upper jaw.
Calling your health care provider
Contact your medical provider if you or your child have a chronic skin or bone lesion and have resided in tropical areas where yaws is endemic .
Prevention
Mass campaigns for eradication of yaws via penicillin treatment in the 1950s and 1960s have dramatically decreased the worldwide incidence of yaws.