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Alternative NamesFrambesia tropica
Definition Return to top
Yaws is a long-term (chronic) infection that mainly affects the skin, bones, and joints.
Causes Return to top
Yaws is an infection caused by the spiral-shaped bacteria, Treponema pertenue. It is closely related to the bacteria that cause syphilis, but this disease is not sexually transmitted. Yaws mainly affects children in rural, warm, tropical areas, such as the Caribbean Islands, Latin America, West Africa, India, and Southeast Asia.
Yaws is transmitted by direct contact with the skin sores of infected people.
Symptoms Return to top
About 2 - 4 weeks after infection, the child develops a sore called a "mother yaw" where the bacteria entered the skin. The sore is a growth that looks like a raspberry. It is usually painless. These sores may last for months. More sores may appear shortly before or after the mother yaw heals.
Other symptoms include:
In the final stage, sores on the skin and bones can lead to severe disfigurement and disability. This occurs in up to 20% of people who do not get treatment.
Exams and Tests Return to top
A sample from a skin sore is examined under a special type of microscope (darkfield examination). There is no blood test for yaws. However, the blood tests for syphilis may be positive in yaws because the two conditions are closely related.
Treatment Return to top
Treatment involves a single dose of penicillin G. It is rare for the disease to return.
Outlook (Prognosis) Return to top
If treated in its early stages, yaws can be cured. Skin lesions may take several months to heal.
By its late stage, yaws may have already caused damage to the skin and bones. It may not be fully reversible, even with treatment.
Possible Complications Return to top
Yaws may damage the skin and bones, affecting the appearance and ability to move. It can also cause deformities of the legs, nose, palate, and upper jaw.
When to Contact a Medical Professional Return to top
Contact your health care provider if you or your child has sores on the skin or bone that don't go away, and you have stayed in tropical areas where yaws is known to occur.
Prevention Return to top
Widespread campaigns in the 1950s and 1960s to wipe out yaws through penicillin treatment have dramatically decreased the number of cases worldwide.
References Return to top
Hook III EW. Nonsyphilitic Treponematoses. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 341.Update Date: 8/1/2008 Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.