What is Yaws? Know all about Yaws: a rare disease

What is Yaws? 

Yaws is a type of bacterial infection that can cause chronic disability and disfiguring when left untreated. It is a rare childhood disease that affects the skin, bone and cartilage. 

It is caused by a bacteria that causes syphilis. However, yaws is not a venereal or sexually transmitted disease. 

Yaws is a disease mainly found in tropical forests area with warm and humid conditions. It is also noted in the areas where there is lack of proper sanitation or are located far away from the health services such as the rural areas which are deprived of the primary health care facilities.

What are the causes of Yaws? 

Yaws is caused by a bacteria named Treponema. The subspecies name is pertenue.  Treponema palidum is a bacteria that can cause, endemic syphilis, pinta, beejel and yaws.  The bacteria grows slowly and gradually and affects the skin bone and cartilage of the infected child. 

What are the risk factors for Yaws? 

The following are the risk factors that contribute to the infection and spread of yaws amongst children: 

1. Poverty

2. Low social and economical status 

3. Living in endemic areas of Yaws

4. Warm, humid and tropical forests area

5. No access to health care services

6. Living in slums/crowds and area with lack of sanitation

7. Lack of personal hygiene

Is Yaws a contagious disease? 

Yaws is a contagious disease and humans are the only reservoir. The infection can spread through direct contact with the skin lesions of the infected child. 

The disease is not transmitted from pregnant woman to the fetus. 

What is the incubation period of Yaws? 

The incubation period of Yaws is believed to be between 9 to 90 days. The average known incubation period is  21 days. The bacteria enters through the minor cuts and leisons on the skin and reach the blood stream. The infection spreads from person-to-person.  

Which age group is most commonly affected by Yaws? 

Both male and female children below 15 years of age are seen to be infected with yaws.  

The most common age group is between 6 to 10 years of age. 

Failure or severe delay of treatment may lead to potential complications such as chronic disability and disfiguring of the body parts. 

What are the stages of Yaws infection? 

Yaws infection occurs in three stages: 

Early stage yaws:  

The sores may start to form firstly on the lower legs, here the sores proliferate to make a raspberry cluster. It is called mother yaws. 

The adjacent lymph nodes may swell up due to the infection.  The infection then continues to spread to the nearby areas,forming smaller clusters. This is called daughter yaws. 

The sores may break open and ulcers may form with thin yellow-crust on the top. When a healthy person's skin with minor cuts or scratches comes in contact with such open sores, he gets infected with Yaws.

Second stage yaws: 

In the second stage or crab yaws,  the infection spreads to more parts such as face, buttocks, feet, genitals, etc. The skin lesions may develop on the soles too. The person may find it difficult to walk and may walk like a crab, hence the name crab yaws. 

Both early and second stages are more infectious and can spread the bacteria to a healthy person through skin-to-skin transmission. 

Latent or last stage yaws: 

In the latent phase or last stage of yaws, the disease spreads more extensively and deeper affecting the bones and cartilage tissues. This results into chronic disability if left untreated.  Conditions such as Gondou syndrome, rhinopharngitis mutilans or gangosa syndrome may develop in 10% people who progress to the latent stage of yaws. These conditions may cause facial disfiguring and painful skin nodules, severe bone and joint pain and may cause impairment of joint function and mobility over time. 

What are the signs ans symptoms of Yaws? 

The signs and symptoms of Yaws are as below: 

• Formation of itchy sores on the lower legs
• Swollen lymph nodes 
• Feeling fatigue 
• Loss of appetite
• Difficulty in walking, Crab gait(crab yaws due to the sores on the soles and feet)
• Pain in the bones and joints
• Disfigured hands, nose and face due to deep penetration of the sores. (late stage yaws)

The infection begins as a skin sore. The sores mostly start on the lower legs which then spread rapidly.  The initial sore may look like a papilloma or a wart. This turns into ulcers and these ulcers may bleed. The open cuts and ulcers when come in direct skin contact with another person causing infection. 

Yaws can be divided into three stages. 

The first stage marks the formation of the skin lesions such as papules and nodules on the outer layer of skin made up of solid epidermal tissues. The second stage includes the proliferation of the nodules to form a bunch-like appearance, as in strawberry or cauliflower.  At this stage the lesions may turn into sores and ulcer which break open and scarring occurs. The first and second stage are not so serious but are the most infectious ones. 

As the infection advances, the bones and cartilages are damaged and the resulting complications are chronic disability and disfiguring of the various affected body parts. 

How is the diagnosis of Yaws made? 

It can be done by physical assessment of the infected child. Blood tests may be done to detect yaws. PCR tests may  be done to check the DNA material of the bacteria in the skin lesions. There are Treponema rapid detection tests but they may not confirm the treponema that causes Yaws, 

What is the treatment of Yaws? 

Yaws can be treated easily when detected early, before the complications start to occur. 

A single dose of broad-spectrum antibiotics is sufficient to eliminate the bacterial infection. Yaws can be treated by a single dose of azithromycin or benzathine penicillin whichever is suitable to the patient's body. 

A single does of azithromycin works best for all and is the most preferred treatment option. 

The penicillin can, however be needed for the patients who are resistant to azithromycin or show failure of treatment. 

The skin samples are reexamined for the bacteria within a month. Most cases get cured by this single oral dose of antibiotics. 

Is there any vaccine for Yaws? 

Currently there are no vaccines available for Yaws. 

Can Yaws be prevented? 

Yaws can be prevented by proper health education and awareness of the disease. 

Importance of personal hygiene and sanitation can help the people prevent themselves from yaws. It is the best way to control and prevent the yaws infection. 

This blog post is for educational and informational purpose only. It is not a substitute to medical advice, consultation or treatment. See your doctor in any case.