What are the other Names for this Condition? (Also known as/Synonyms)

• Bouba
• Parangi
• Polypapilloma Tropicum

What is Yaws? (Definition/Background Information)

• Yaws is described as a rare and chronic infectious disease that is transmitted non-sexually, usually through skin contact or sharing of contaminated items. The condition is generally seen during childhood and typically affects the skin, bone, and cartilage
• The disease is classified as a treponematosis i.e., infectious disease caused by a spirochete (or spiral-shaped) bacterial organism, called Treponema pallidum pertenue. Yaws is the most common form of non-sexually transmitted Treponema infection
• Initial stages of infection (early Yaws) are generally mild, but the condition can be progressive and severe during the later stages (late Yaws). If left untreated, the skin lesions may be observed all over the body
• Individuals with Yaws may present skin lesions within 2-4 weeks of first exposure, in many cases. This is followed by more lesions that ulcerate and heal. Slowly, the involvement of the bones and joints may be noted. Untreated Yaws can potentially lead to severe physical deformity
• A healthcare provider may diagnose the condition through a physical exam and blood tests, to detect the presence of antibodies against the infection. Upon diagnosis, antibiotics are administered to treat Yaws
• Typically, antibiotic therapy can eliminate the bacteria from the body. Individuals with Yaws have an excellent prognosis, because the condition is curable with suitable treatment. However, a lack of treatment may result in long-term complications, severe cosmetic disfigurement, and disability

Yaws may be classified into the following stages:

• Primary Yaws - when skin lesions develop and heal in 6 months
• Secondary Yaws - it lasts from 6 months to 3 years approximately; multiple skin lesions may be seen with the thickening of palms on one’s hands. The individual remains infectious even during this stage
• Tertiary Yaws - 1 in 10 reach this stage and this may take 5-10 years after the initial infection. In this stage, extensive bone and joint involvement is noted

Who gets Yaws? (Age and Sex Distribution)

• Yaws affects children and adolescents more than adults; about 80% of the cases are seen in children below 15 years of age (peak incidence seen between the ages 6-10 years). However, individuals of any age range may be affected
• Both males and females and individuals of any racial or ethnic background may be affected
• The condition is only present in the hot humid (endemic) regions of the world, especially among economically backward communities
• According to the World Health Organization, Yaws is prevalent in nearly 13 countries that belong to Asia, Africa, South America, and some Pacific Ocean islands. It has been reportedly eradicated from over 70 countries

What are the Risk Factors for Yaws? (Predisposing Factors)

The risk factors for Yaws include the following:

• Residing in or visiting hot and humid countries known to be endemic to the infectious microorganism
• Poverty
• Contact through open wounds
• Poor personal hygiene
• Coming into direct contact with the infected individuals; an unhygienic environment aids in quicker transmission
• Sharing of items with infected individuals
• Overcrowded spaces

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Yaws? (Etiology)

Yaws is a non-venereal (non-sexually transmitted) disease that is caused due to infection by Treponema pallidum pertenue, a spiral-shaped bacterium.

• It is transmitted via direct, but non-sexual, physical contact with an infected individual (usually through minor injuries and open sores)
• Sharing contaminated items, such as kitchen vessels, mattresses, towels, etc., can also result in infection

What are the Signs and Symptoms of Yaws?

The signs and symptoms of Yaws and its progression can vary from one individual to another. It may be mild in some and severe in others. The incubation period (the time between infection and presentation of symptoms) is between 9 days to 3 months, with average period being 3 weeks. The signs and symptoms of Yaws may be grouped as early and late.

Early Yaws signs and symptoms:

• Raised bumps on skin (arms and legs) that can last for 3-6 months; usually, only one lesion of size between 2-5 cm is seen in the initial stages
• If no treatment is provided, the skin lesion may heal, but other similar lesions may appear around the initial skin lesion; and then, all over the body
• Ulceration of the skin lesions can be severe
• Severe fatigue
• Bone can be infected causing bone pain (usually nocturnal)
• The skin lesions may occasionally heal with scars

Late Yaws signs and symptoms:

• It may arise 5 years after early Yaws
• Involvement of the skin, bone, and cartilage is noted
• The long bones of the limbs and finger bones are mostly involved
• Presence of soft nodules of bones called gummas
• Thickening of soles and palms may be observed

How is Yaws Diagnosed?

Yaws may be diagnosed by a healthcare provider using the following tools:

• Complete physical examination and analysis of previous medical and travel history
• Blood tests for antibodies against the organism
• Microscopic examination of tissue samples
• Polymerase chain reaction (PCR) test to confirm a diagnosis of Yaws
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist may arrive at a diagnosis of Yaws

Note:

• A skin biopsy may show the presence of the microorganisms
• A differential diagnosis to eliminate skin rashes caused by the bacterium Hemophilus ducreyi is important, since the condition mimics Yaws

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Yaws?

Complications for Yaws may include the following:

• Cosmetic disfigurement and facial deformities
• Thickening of the soles and palms
• Soft tissue, bone, and joint involvement can be severe, leading to their destruction
• Severe emotional distress due to physical appearance from the lesions (cosmetic issues)
• Yaws can become a chronic skin infection that is debilitating
• Inflammation of bones or periostitis

How is Yaws Treated?

Yaws is a curable disease that is generally treated by healthcare professionals using medications. The healthcare provider may administer the following antibiotics:

• Benzathine penicillin (administered intramuscularly)
• Azithromycin (given orally); it is the preferred choice
• Tetracycline class antibiotics or erythromycin/azithromycin may be used in individuals who are allergic to penicillin

How can Yaws be Prevented?

Currently, there is no vaccine available to prevent Yaws. However, contracting the infection may be avoided by considering the following measures:

• Practicing proper sanitary techniques, such as washing one’s hands, to avoid the spread of infection
• Prior to the antibiotic era, Yaws patients were quarantined from the healthy population
• Keeping wounds clean and well-covered to prevent spread of infection
• Avoiding the endemic hot-humid regions, when possible
• Treating family members and friends who were in contact with the affected individual, to prevent further spread of the condition
• Sometimes, entire communities are known to be treated/sanitized

What is the Prognosis of Yaws? (Outcomes/Resolutions)

• The prognosis for Yaws is generally excellent with adequate and appropriate treatment. Antibiotic therapy can bring about a complete cure, if it is provided in a timely manner
• However, delayed diagnosis and/or a lack of treatment can lead to debilitating disease resulting in severe disfigurement of the face and body. Without treatment, 1 in 10 individuals may have severe physical deformities
• In general, primary and secondary Yaws are known to heal completely without complications with proper treatment. In the tertiary stage, the symptoms may not get worse, but complications causing disfigurement and disability may be permanent

Additional and Relevant Useful Information for Yaws:

• Treponematosis consists of diseases caused by the bacterial species Treponema. It consists of non-sexually transmitted conditions including pinta, bejel, and Yaws, along-with the sexually transmitted infectious disease syphilis

Please visit our Infectious Diseases Health Center for more physician-approved health information:

https://www.dovemed.com/diseases-conditions/infection-center/