Yaws in Children
Introduction to Yaws in Children
Yaws is a chronic, non-venereal, treponematosis primarily affecting children in tropical and subtropical regions. It is caused by the bacterium Treponema pallidum subspecies pertenue. Yaws is characterized by skin lesions and, in later stages, can lead to bone and joint involvement. Although not typically fatal, untreated yaws can cause significant disfigurement and disability.
Key points:
- Yaws is one of the neglected tropical diseases (NTDs) targeted for eradication by the World Health Organization (WHO).
- It primarily affects children under 15 years of age in rural, tropical areas with poor hygiene and sanitation.
- The disease is transmitted through direct skin-to-skin contact with infectious lesions.
- Early diagnosis and treatment are crucial to prevent complications and reduce transmission.
Etiology of Yaws
Yaws is caused by the spirochete bacterium Treponema pallidum subspecies pertenue. This organism is closely related to the causative agents of other treponematoses, including syphilis (T. pallidum subsp. pallidum) and endemic syphilis (bejel, T. pallidum subsp. endemicum).
Key characteristics of T. pallidum subsp. pertenue:
- Gram-negative, spiral-shaped bacterium
- Cannot be cultured in vitro
- Transmitted through direct contact with infectious lesions
- Highly sensitive to penicillin and other antibiotics
The bacterium enters the body through small breaks in the skin and multiplies locally, leading to the formation of the characteristic primary lesion, known as the "mother yaw."
Epidemiology of Yaws
Yaws is endemic in tropical and subtropical regions, particularly in areas with poor sanitation and hygiene practices. The disease primarily affects children under 15 years of age.
Key epidemiological features:
- Geographic distribution: Mainly in parts of Africa, Southeast Asia, and the Western Pacific
- Age distribution: 75-80% of cases occur in children aged 2-15 years
- Transmission: Direct skin-to-skin contact with infectious lesions
- Risk factors: Poverty, overcrowding, limited access to healthcare, poor personal hygiene
Global efforts to eradicate yaws:
- WHO launched the Global Yaws Eradication Programme in 1952
- Significant reduction in cases by the 1970s, but resurgence occurred in some areas
- In 2012, WHO developed the Morges Strategy for yaws eradication by 2020 (later extended)
- Current approach: Total Community Treatment (TCT) with azithromycin
Clinical Manifestations of Yaws
Yaws progresses through three stages, each with distinct clinical features:
1. Primary Stage (Early Yaws)
- Incubation period: 9-90 days (average 21 days)
- Primary lesion: "Mother yaw" - a papule that evolves into a papilloma
- Characteristics: Painless, friable, 2-5 cm in diameter, often on legs or feet
- Regional lymphadenopathy may be present
2. Secondary Stage (2 weeks to 6 months after primary infection)
- Multiple skin lesions: Papillomas, macules, papules, and hyperkeratotic plaques
- "Crab yaws" on palms and soles
- Bone involvement: Periostitis and osteitis, causing nocturnal bone pain
- Constitutional symptoms: Fever, malaise, arthralgias
3. Tertiary Stage (5+ years after initial infection, in untreated cases)
- Gummatous lesions: Destructive skin ulcerations and nodules
- Bone and joint deformities: Sabre tibia, gangosa (destructive rhinopharyngitis)
- Hypertrophic periostitis and osteitis
- Juxta-articular nodules
Note: Unlike syphilis, yaws does not affect the central nervous system or cardiovascular system.
Diagnosis of Yaws
Diagnosis of yaws is based on clinical presentation, epidemiological context, and laboratory tests. Definitive diagnosis requires the detection of T. pallidum subspecies pertenue.
Clinical Diagnosis
- Characteristic skin lesions in a child from an endemic area
- History of exposure to infected individuals
- Presence of bone pain or joint involvement
Laboratory Tests
- Direct detection methods:
- Dark-field microscopy: Visualization of spirochetes from lesion exudate
- Polymerase Chain Reaction (PCR): Most specific test, can differentiate yaws from other treponematoses
- Serological tests:
- Non-treponemal tests: Rapid Plasma Reagin (RPR), Venereal Disease Research Laboratory (VDRL)
- Treponemal tests: Treponema Pallidum Hemagglutination Assay (TPHA), Fluorescent Treponemal Antibody Absorption (FTA-ABS)
Differential Diagnosis
Consider other conditions such as:
- Cutaneous leishmaniasis
- Tropical ulcers
- Psoriasis
- Leprosy
- Other treponematoses (e.g., endemic syphilis, venereal syphilis)
Treatment of Yaws
The treatment of yaws aims to cure the infection, prevent transmission, and avoid long-term complications. The World Health Organization (WHO) recommends the following treatment strategies:
Individual Treatment
- First-line treatment:
- Azithromycin: Single oral dose of 30 mg/kg (maximum 2 g)
- Alternative treatment (if azithromycin is unavailable or contraindicated):
- Benzathine benzylpenicillin: Single intramuscular injection
- Children under 10 years: 600,000 units
- Adults and children 10 years and older: 1,200,000 units
- Benzathine benzylpenicillin: Single intramuscular injection
Mass Drug Administration (MDA)
In endemic communities, WHO recommends Total Community Treatment (TCT):
- Treat the entire endemic community with single-dose azithromycin
- Aim: To treat both clinical cases and latent infections
- Follow-up surveys and additional TCT rounds may be necessary
Treatment Follow-up
- Clinical improvement is usually seen within 2-4 weeks
- Serological tests may remain positive for months or years after treatment
- Monitor patients for treatment failure or reinfection
Note: Treatment of contacts and family members is crucial to prevent reinfection and break the transmission cycle.
Prevention of Yaws
Prevention of yaws involves a multifaceted approach targeting both individual and community-level interventions. Key strategies include:
1. Mass Drug Administration (MDA)
- Total Community Treatment (TCT) with azithromycin in endemic areas
- Aims to treat both clinical cases and latent infections
- Repeat rounds of TCT may be necessary based on follow-up surveys
2. Improved Hygiene and Sanitation
- Promote personal hygiene practices, especially among children
- Improve access to clean water and sanitation facilities
- Encourage the use of soap and proper wound care
3. Health Education
- Raise awareness about yaws transmission, symptoms, and treatment
- Educate communities on the importance of early diagnosis and treatment
- Promote behavior change to reduce transmission risk
4. Active Case Finding and Contact Tracing
- Implement regular screening programs in endemic areas
- Identify and treat contacts of confirmed cases
- Integrate yaws surveillance into existing health systems
5. Environmental Interventions
- Improve housing conditions to reduce overcrowding
- Enhance community infrastructure to support better hygiene practices
6. Strengthening Health Systems
- Train healthcare workers in yaws diagnosis and management
- Ensure availability of diagnostic tools and treatment in endemic areas
- Integrate yaws control into primary health care services
The ultimate goal of these prevention strategies is to interrupt transmission and achieve global eradication of yaws, as targeted by the World Health Organization.
Yaws in Children
- What is the causative agent of yaws?
Treponema pallidum subspecies pertenue - Which age group is most commonly affected by yaws?
Children between 2 and 15 years old - What is the primary mode of transmission for yaws?
Direct skin-to-skin contact with an infected person - Which body areas are most commonly affected in the primary stage of yaws?
Lower extremities and buttocks - What is the characteristic lesion in the primary stage of yaws called?
Mother yaw or primary yaw - How long after infection does the primary lesion of yaws typically appear?
3-4 weeks - What is the appearance of the primary yaw lesion?
A papule that evolves into a painless, raspberry-like, friable growth - Which stage of yaws is characterized by widespread skin lesions and bone involvement?
Secondary stage - What type of bone deformity can occur in long-standing yaws infections?
Sabre tibia (anterior bowing of the tibia) - Which diagnostic test is most commonly used to confirm yaws infection?
Rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test - What is the gold standard treatment for yaws according to WHO guidelines?
Single dose of azithromycin - What is the alternative treatment for yaws if azithromycin is unavailable?
Intramuscular benzathine penicillin G - Which continent has the highest prevalence of yaws cases?
Africa - What is the WHO's goal regarding yaws?
Global eradication by 2030 - How does yaws differ from syphilis in terms of transmission?
Yaws is not sexually transmitted, while syphilis is primarily sexually transmitted - What is the Romani sign in yaws?
Papillomatous lesions on the soles of the feet - Which stage of yaws can lead to destructive lesions of the skin, bones, and cartilage?
Tertiary stage - What is "piano-key" arthralgia in yaws?
Pain in the fingers and toes when pressure is applied - How long can latent yaws persist without treatment?
Up to several years - What is the typical incubation period for yaws?
9-90 days - Which environmental factors contribute to the prevalence of yaws?
Warm, humid climates and poor hygiene conditions - What is the "fifty-cent sign" in yaws?
Circular, scaly patches on the face or body - How does yaws affect the nasopharyngeal region?
It can cause destructive lesions leading to goundou (swelling of nasal bones) - What is the main difference between yaws and endemic syphilis?
Yaws primarily affects the skin and bones, while endemic syphilis can also affect internal organs - Which age group is least commonly affected by yaws?
Adults over 30 years old - What is the recommended follow-up period after treatment for yaws?
6-12 months - How does yaws impact school attendance in endemic areas?
It can lead to decreased attendance due to stigma and physical discomfort - What is the role of flies in the transmission of yaws?
They can act as mechanical vectors, transferring the bacteria from one person to another - Which serological test is used to distinguish yaws from syphilis?
Treponema pallidum particle agglutination (TPPA) test - What is the primary prevention strategy for yaws?
Improving hygiene and living conditions in endemic areas
