Yaws

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

How do health-care professionals diagnose yaws?

Yaws is suspected in any child who has the characteristic clinical features and lives in an area where the disease is common. With increasing travel, a child once in the tropics may carry the disease to a more temperate area of the world.

Laboratory confirmation of the diagnosis is by blood serum tests (for example, RPR or rapid plasma reagent test, VDRL test or venereal disease research laboratory test, TPHA or Treponema pallidum hemagglutination test, FTA-ABS or fluorescent treponema antibody absorption), but most frequently the diagnosis is made on clinical findings. The reason that T. pallidum serum tests are used is that the spirochetes are so closely related, they have similar antigens on their surfaces so that T. pallidum and T. pertenue are cross-reactive (detected by the same serological tests). Special (dark-field) examination under the microscope in which technicians can actually see the spirochete bacterium is also used to help diagnose yaws. The lesions (both the mother yaw and the secondary lesions) usually have many T. pertenue organisms that can be visualized with dark-field examination of lesion scrapings. On a typical Gram stain (a procedure for identifying bacteria when viewed microscopically), the organisms are considered to be Gram-negative but stain so poorly and are so small and thin, the Gram stain often does not reveal the organisms; hence the use of the dark-field examination. Other tests that detect spirochetes such as a silver stain or electron microscopy are used mainly by research scientists. PCR tests can confirm yaws by detecting genetic material from organisms in samples from skin lesions.

What is the treatment for yaws?

Treatment of yaws is simple and highly effective. Penicillin G benzathine given IM (intramuscularly) can cure the disease in the primary, secondary, and usually in the latent phase. Penicillin V can be given orally for about seven to 10 days, but this route is less reliable than direct injection. Anyone allergic to penicillin can be treated with another antibiotic, usually erythromycin, doxycycline, or tetracycline. Azithromycin (in a single oral dose of 30 mg/kg or the maximum 2 g) is the choice that the World Health Organization (WHO) recommends because of the ease of administration. Tertiary yaws, which occurs in about 10% of untreated patients five to 10 years after initially getting the disease, is not contagious. The tertiary yaws patient is treated for the symptoms of the chronic conditions (altered or destroyed areas in bones, joints, cartilage, and soft tissues) that develop as complications of the infection. There is no vaccine for yaws.

Medically Reviewed by a Doctor on 9/13/2016

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