Yaws is a chronic infection caused by the spirochete bacteria called Treponema pallidum pertenu infecting skin, bones and joints. Yaws resembles syphilis but is not sexually transmitted rather it is transmitted by direct contact with the skin sores of infected person. Yaws infection is restricted to warm tropical areas only and is common in rural areas of South America, Africa, India and South East Asia. Yaws is characterized by development of mother yaws which is skin lesion or nodule which enlarges and develops into a crust like form which is then shed leaving a sore which has a texture which resembles raspberry. Mother yaw is followed by daughter yaws on the adjoining areas of infection. Yaws infection usually affects children below the age of fifteen years but can happen to anyone and of any age. Males are more prone to be infected by yaws as compared to females.
Yaws is caused by a spherical bacterium called Treponema pallidum perten. Yaws is transmitted through direct contact with the open sores of infected person. The bacteria causing yaws is closely related to bacteria causing syphilis and even the symptoms are often similar to syphilis. Yaws is prevalent in tropical warm and humid regions. It becomes a wide spread epidemic in tribal areas because of unhygienic social environment.
The incubation period of yaws is generally 3-5 weeks. After the incubation period a primary lesion called “mother yaws” appears at the spot from where the bacteria entered the skin. The mother yaws is painless and when enlarged, it appears like a raspberry. The infection can also occur at the genitals and other exposed part of the body such as face, buttocks, arms, legs, shoulders etc. The local lymph glands are enlarged during the infection and the blood test appears positive for STS. Sometimes daughter yaws also appear in the regions surrounding the mother yaws. The primary stage lasts for almost two months. After the primary stage, additional lesions appear on the body which shed the outer most membrane or skin on getting ripe. These secondary lesions heal and re-appear automatically. During the next couple of years skin lesions may appear at regular intervals including bone, periosteum and mucous membrane lesions. After five years of infection, the patient develops destructive and deforming lesions which might even cripple the patient making him/her dependent on others. Lesions called crab yaws also appears on sole and palms during the later stages of the infection. Other symptoms of Yaws are Skin and bone swelling, swelling of the fingers, bone pain and scarring of the skin.
The diagnosis of Yaws is done using darkfield microscopic examination. A sample of infectious sore is taken and examined under a special microscope. Blood test such as VDRL, Rapid Plasma Reagin and TPHA may also be suggested by doctors. However there is no specific blood test for yaws. The blood tests mentioned will test positive in case of infection caused by any of the four types ofTreponema bacteria.
The treatment for yaws is penicillin shots. Doctors go for single dose of intramuscular penicillin or in some case a course of penicillin, erythromycin or tetracycline tablets. The treatment also includes community treatment to prevent transmission. In case the person is crippled or has permanent damage to bones, then those damages are irreversible. Hence it is advised to consult the doctor immediately in case you or your children have sores on the skin and bones which do not heal within a week. Consulting a doctor becomes imperative in case you reside in tropical region where yaws occur quite often.
There is no known prevention particularly against yaws. It is advised to maintain hygienic lifestyle. In case you have any infected person in your community or family then avoid direct skin contact with the infected person and take him to the nearest health care unit immediately. Spread awareness about Yaws and its complications in your community.