Yaws is a chronic illness that first affects the skin, and later the bones.
Yaws tends to strike children, particularly between the ages of two and five.It is common in areas where poverty and overcrowding interfere with good hygiene. It is most prevalent in rural areas throughout Africa, Southeast Asia,and in locations bordering the equator in the Americas.
Yaws is caused by a spiral-shaped bacterium (spirochete) called Treponemapertenue. This bacterium belongs to the same family as the bacterium thatcauses syphilis.
Yaws is passed among people by direct skin contact. The bacterium requires ascratch or insect bite to actually settle in and cause infection. An injury on the leg is the most common part of the body through which the bacteria enter. Young children, who are constantly bumping themselves in play, who wear little clothing, who do not wash their hands often, and who frequently put their hands in their mouths, are particularly susceptible to yaws.
The first symptom of this disease occurs three to four weeks after bacterialinfection. The area where the bacteria originally entered the skin becomes anoticeable bump (papule). The papule grows larger and develops a punched-outcenter (ulcer), covered with a yellow crust. Adjacent lymph nodes may becomeswollen and tender. The first papule may take as long as six months to heal.Secondary soft, gummy growths then appear on the face, arms and legs, and buttocks. These soft, tumor-like masses may also grow on the soles of the feet,causing the patient to walk in an odd and characteristic fashion on the sidesof his or her feet (nicknamed "crab yaws"). More destructive tumors may thendisrupt the bones of the face, the jaw, and the lower leg. Ulcers around thenose and on the face may be very mutilating.
Samples taken from the first papules may be examined using a technique calleddark-field microscopy. This often allows the spirochetes to be identified. They may also be identified in fluid withdrawn from swollen lymph nodes. Various tests can also be run on blood samples to determine if an individual is producing antibodies (special immune cells) in response to the presence of these spirochetes.
A single penicillin injection in a muscle is sufficient to completely end thedisease.
Without treatment, yaws is a terribly disfiguring chronic illness. With appropriate treatment, progression of the disease can be completely halted.
The World Health Organization (WHO) has been working to totally eradicate yaws, just as smallpox was successfully eradicated. This has not occurred, however. WHO continues to work to identify and respond to outbreaks quickly, in aneffort to at least slow the spread of yaws.