Information on the following diseases can be found in the Related Disorders section of this report:

• Bejel
• Syphilis, Acquired
• Pinta
• Leprosy

Stage 1 yaws typically occurs in early childhood, with peak incidence at about six years of age. A single itchy, strawberry-like growth appears on the skin over which a thin yellow crust forms (papillomatous lesion). This growth, the "mother yaw", appears at the spot where the organism entered the body (inoculation site), typically on the leg or foot.

Stage 2 yaws typically follows several weeks or months after the initial symptoms. Similar skin sores appear on the face, legs, arms, and/or around the rectum and genitals. These sores usually heal slowly and may recur. Lesions on the bottom of the feet may produce painful cracks and ulcerations (keratosis), resulting in an awkward "crab-like" walk or "crab yaws."

At this stage, swollen glands (swollen lymph nodes) are not uncommon and the rash may develop a brown crust.

The symptoms of stage 3 yaws occur in only about 10% of the people who are infected and may follow a dormant period of several years. Painful ulcers or nodules may develop on the skin (cutaneous) and cause facial disfigurement. Painful, granular sores (gummatous lesions) may also develop on the bones, especially the long bones of the legs (tibia). Painful skin and bone nodules may impair joint function and mobility.

Stage 3 yaws may also produce different and distinct syndromes. One, known as goundou syndrome, is characterized by inflammation and swelling of the tissues surrounding the nose (paranasal swelling), as well as overgrowth of the bones in the same region of the face (hypertrophic osteitis). Another, known as gangosa syndrome (also known as rhinopharyngitis mutilans), is characterized by degenerative changes of the nose, throat (pharynx), and the roof of the mouth (hard palate).
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Yaws is an infectious disease caused by a spiral-shaped bacterium (spirochete) known as Treponema pertenue. Yaws is usually transmitted by direct contact with the infected skin sores of affected individuals. In some cases, yaws may be transmitted through the bite of an infected insect.

Yaws is a common infectious disease among children living in the tropical areas of Africa, South and Central America, the West Indies, and the Far East. It is rare in the United States. Yaws affects males and females in equal numbers and is most common in children between the ages of six and 10.

The prevalence of yaws declined greatly following a mass treatment campaign with penicillin by the World Health Organization (WHO) in the 1950s and ‘60s. However, there has been a resurgence of yaws in certain countries in Africa and Southeast Asia.

Symptoms of the following disorders can be similar to those of Yaws. Comparisons may be useful for a differential diagnosis:

Bejel is an infectious disease which is rare in the United States but common in certain parts of the world. It is characterized by lesions of the skin and bones and is caused by a bacteria known as Treponema pallidum II. The infection is very similar to syphilis but is not sexually transmitted. Children with Bejel have patchy ulcerations on mucous membranes particularly in or near the mouth. (For more information on this disorder, choose "Bejel" as your search term in the Rare Disease Database.)

Acquired Syphilis is a chronic infectious disease caused by the bacteria Treponema pallidum. It is transmitted by direct contact with an infected individual, usually through sexual intercourse. When left untreated, the symptoms of Syphilis progress (i.e., primary, secondary, and latent stages). Eventually any tissue or organ in the body may be affected. Early symptoms include lesions (chancres) of the skin, anus, vagina, or the moist surfaces of the mouth. The symptoms may remain dormant for years. (For more information on this disorder, choose "Syphilis" as your search term in the Rare Disease Database.)

Pinta is a rare infectious disease characterized by skin rash and discoloration. It is caused by the spiral-shaped bacteria Treponema carateum. Pimple-like bumps appear on the skin; they are small, reddish, and patchy. These lesions change in color and eventually lose all color (depigmentation). Pinta may be acquired by direct nonsexual contact. (For more information on this disorder, choose "Pinta" as your search term in the Rare Disease Database.)

Leprosy is a progressive, chronic infectious disease caused by the bacteria, Mycobacterium leprae. This disease affects the nerves that are located outside the central nervous system (peripheral nerves), and the skin, mucous membranes, and eyes. In severe cases of Leprosy, loss of sensation, disfigurement, and/or blindness may occur. Symptoms may include burning or tingling sensations (paresthesias), a lack of sensation or feeling in the affected areas (anesthesia), weakness, paralysis, and/or the loss of muscle tissue (atrophy). Skin lesions include flat, spotty discolorations (macules), raised areas of red skin (papules), small solid masses (nodules), and raised discolorations. (For more information on this disorder, choose "Leprosy" as your search term in the Rare Disease Database.)

Diagnosis
The diagnosis of stage 1 and stage 2 yaws is made by microscopic examination of tissue samples (darkfield examination) from the skin lesions of affected individuals. Stage 3 yaws may be diagnosed by specialized blood tests (i.e., VDRL and treponemal antibodies).

Treatment
Stage 1 and 2 yaws is treated with antibiotics, especially with benzathine penicillin G. A single large dose of these medications usually heals the skin lesions and eliminates the organism. These antibiotic drugs may also be used to prevent this disease in family members and others who are in frequent contact with affected individuals. At the present time, there is no treatment for the destructive bone lesions or scars associated with stage 3 yaws.
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Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

Research on tropical diseases such as yaws is ongoing. For more information about these disorders, contact the World Health Organization (WHO) or Centers for Disease Control and Prevention (CDC) listed in the Resources section of this report.

TEXTBOOKS
Perine PL. Endemic Treponematoses. In: Fauci AS, Braunwald E, Isselbacher KJ, et al. Eds. Harrison’s Principles of Internal Medicine. 14th ed. McGraw-Hill Companies. New York, NY; 1998:1033-36.

Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:1185-86.

Berkow R., ed. The Merck Manual-Home Edition.2nd ed. Whitehouse Station, NJ: Merck Research Laboratories; 2003:1099.

Azimi P. Spirochetal Infections; Non Venereal Syphilitic Diseases. In: Behrman RE, Kliegman RM, Arvin AM. Eds. Nelson Textbook of Pediatrics. 15th ed. W.B. Saunder Company. Philadelphia, PA; 1996:856-57.

REVIEW ARTICLES
Antal GM, Lukehart SA, Meheus AZ. The endemic treponematoses. Microbes Infect. 2002;4:83-94.

Arteaga C, Gueguen GE, Richez P, et al. [Osteoarticular involvement in parasitic diseases: bone treponematosis]. J Radiol. 1998;79:1363-66.

JOURNAL ARTICLES
Anselmi M, Moreira JM, Caicedo C, et al. Community participation eliminates yaws in Ecuador. Trop Med Int Health. 2003;8:634-38.

Scolnik D, Aronson L, Lovinsky R, et al. Efficacy of a targeted oral penicillin-based yaws control program amoung children living in rural South America. Clin Infect Dis. 2003;36:1232-38.

Wicher K, Wicher V, Abbruscato F, et al. Treponema pallidum subsp. pertenue displays pathogenic properties different from those of T. pallidum subsp. pallidum. Infect Immun. 2000;68:3219-25.

Koff AB, Rosen T. Nonveneral treponematoses: yaws, endemic syphilis, and pinta. J Am Acad Derm. 1993;29:4:83-94.

FROM THE INTERNET
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www.emedicine.com/med/topic2431.htm

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Kotton C. Yaws. MEDLINEplus. Medical Encyclopedia. Update Date: 2/17/2003
www.nlm.nih.gov/medlineplus/ency/article/001341.htm

Yaws. Aetna IntelliHealth. Last Updated: February 28, 2002. 3pp.
www.intelihealth.com/IH/ihtIH/WSIHW000/9339/23810.html

Hicks R. Yaws: Catching a raspberry. BBC1 Health. nd. 2pp.
www.bbc.co.uk/health/features/yaws/shtml

Yaws. The 1911 Edition ENCYCLOPEDIA. nd. 4pp.
http://5.1911encyclopedia.org/Y/YA/YAWS.htm

Carson-DeWitt R. Yaws. healhAtoZ. Gale Encyclopedia of Medicine Ó2002. 3pp.
www.healthatoz.com/healthatoz/Atoz/ency/yaws.html