from Alternative names
pian; tropica; patek; parangi; bouba; frambesia

An infectious disease that is similar to syphilis but is not sexually transmitted.

Causes, incidence, and risk factors
Yaws is very similar to syphilis, but it is not sexually transmitted. It is caused by the spiral-shaped bacterium (spirochete) called Treponema pertenue that is closely related to the organism that causes syphilis (Treponema pallidum).

Yaws is found in humid regions near the equator (tropical and subtropical regions). It almost always occurs in poor children.

Approximately 3 to 4 weeks after infection with the spirochete, the child develops a sore ("mother yaw") where the organism entered the skin. The sore is a highly infectious, very itchy, "raspberry-like" growth or group of papules at the site of infection. Scratching spreads the infection and more growths begin to appear elsewhere on the body.

Like syphilis, this disease has a latent period when it is inactive, followed by external and internal lesions which destroy skin, bone and other tissues.

Yaws is spread by direct contact.

Infection with yaws MAY be protective against syphilis, but this has not been conclusively proven.

Avoid direct contact with a yaws skin lesion.


  • fever
  • joint pain
  • initial, single skin growth that looks like a raspberry and itches severely
  • this growth eventually opens up to form a skin ulcer
  • new growths (tubercles) appear on the hands, feet, genitals, and other areas
  • skin lesions may have a cheesy (caseous) crust

Signs and Tests
Blood tests for syphilis.

A single, large dose of penicillin G is given by intramuscular injection. This cures the infection.

Yaws lesions will heal slowly even without treatment, but this may take 6 months or more and recurrence is common. Before healing, the lesions destroy soft tissue and bone.

Yaws can cause gross destruction of the skin, bones, and joints. This can cause deformities of the legs, nose, palate, and upper jaw. The disorder is crippling if untreated. Approximately 10% of the people with yaws will develop widespread tissue damage.

Yaws (?), n. [African yaw a raspberry.] Med.

A disease, occurring in the Antilles and in Africa, characterized by yellowish or reddish tumors, of a contagious character, which, in shape and appearance, often resemble currants, strawberries, or raspberries. There are several varieties of this disease, variously known as frambesia, pian, verrugas, and crab-yaws.


© Webster 1913.

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