Bone and joint lesions of yaws.Care & specialists in India

Yes. Yaws is endemic in 13 countries, with about 46,000 confirmed cases reported globally in 2022 (WHO). Papua New Guinea, the Solomon Islands, and several West and Central African countries carry most of the burden. WHO has set 2030 as the eradication target.

Yaws spreads by direct skin-to-skin contact, usually through minor cuts, scratches, or insect bites. It is not sexually transmitted, not congenital, and not spread by food, water, or insect vectors. Most transmission happens between children playing or sharing bedding in close contact.

Yes, but it is uncommon. About 75-80% of new cases occur in children under 15. Adults in endemic areas are usually partially protected by childhood immunity. Travelers can occasionally acquire it after prolonged stays in rural endemic areas.

The first lesion (the 'mother yaw') is a single, painless, raspberry-like papilloma, typically 1-5 cm wide, on the leg, foot, or buttock. It appears 9-90 days after exposure, does not hurt unless secondarily infected, and heals slowly over months even without treatment.

The primary papilloma is usually painless. Pain becomes more prominent in secondary disease — painful sole thickening (plantar hyperkeratosis) and bone pain in the tibia and forearms. The difficulty walking on flat feet gave rise to the name 'crab yaws'.

Both are caused by closely related subspecies of Treponema pallidum and serology cannot distinguish them. Syphilis is sexually transmitted, can be congenital, and is global. Yaws is non-venereal, affects children, and occurs only in tropical regions.

Diagnosis is clinical plus serologic. A characteristic papilloma in a child in an endemic area plus a positive rapid treponemal test (DPP) makes the diagnosis. Quantitative RPR or VDRL confirms active disease and monitors treatment. PCR on lesion swabs is the gold standard.

A single oral dose of azithromycin at 30 mg/kg (maximum 2 g) cures over 95% of cases. This replaced intramuscular benzathine penicillin as first-line in 2012 because pills are easier to give at community scale. Penicillin remains the alternative for pregnancy or resistance.

Patients are no longer infectious within 24 hours of azithromycin or benzathine penicillin. Primary lesions begin to flatten within 1-2 weeks and heal over 4-8 weeks. Bone pain settles within 2-4 weeks. Antibody titers (RPR) take 3-6 months to fall fourfold, which is the laboratory marker of cure.

Relapse is rare with adequate treatment but does occur in 1-3% of cases, usually within 6 months. Re-treatment with a second dose of azithromycin, or switching to benzathine penicillin, cures most relapses. Persistent failure should prompt PCR testing for the 23S rRNA macrolide-resistance mutation.

No vaccine for yaws is currently available. Eradication relies on mass drug administration with azithromycin, contact tracing, and improved community hygiene. A vaccine has been technically feasible but not prioritized because oral antibiotic therapy is already highly effective.

WHO lists 13 endemic countries: Cameroon, Central African Republic, Congo, DRC, Côte d'Ivoire, Ghana, Indonesia, Liberia, Papua New Guinea, Solomon Islands, Timor-Leste, Togo, and Vanuatu. Papua New Guinea and Solomon Islands together account for over 70% of reported cases.

Yaws affects only humans, has no animal reservoir, has a sensitive single-dose oral treatment, and is geographically confined. These features make it biologically eradicable — similar to smallpox. WHO set 2030 as the eradication target.

Gangosa is the destructive late-stage facial lesion of untreated tertiary yaws, eroding the nose, palate, and pharynx. It develops 5-10 years after primary infection. Modern surveillance has essentially eliminated new gangosa; most living cases reflect pre-1970s untreated childhood infections.

No. Yaws is not a sexually transmitted infection. Sexual transmission has not been demonstrated for T. pertenue. Adolescent cases with positive treponemal serology require careful history-taking to distinguish yaws from acquired syphilis.

Yaws itself is rarely fatal. The historical burden has been disfigurement, school absence, and stigma rather than mortality. Death from yaws occurs only in extreme tertiary cases with secondary bacterial sepsis or in severely malnourished children with overwhelming co-infection.

A 2018 outbreak in Papua New Guinea identified yaws strains with the A2058G mutation in 23S rRNA, conferring high-level azithromycin resistance. Benzathine penicillin remains universally effective, and resistance has not spread widely outside the original outbreak focus.

Risk to short-term travelers is very low. Yaws requires repeated close skin contact in rural endemic communities, typically over weeks to months. Any persistent unhealed skin papilloma after travel should be assessed by a tropical medicine clinician. No vaccine exists.

WHO's Morges Strategy involves total community treatment — every resident receives a single oral dose of azithromycin on a designated day, with coverage above 90% as the target. Re-surveys every 6-12 months identify new cases for repeat treatment until 3 consecutive years without new cases.

Partial prevention is possible through improved hygiene — handwashing, soap, footwear, prompt cleaning of cuts — which reduces incidence by 30-50%. However, hygiene alone has not eliminated yaws anywhere.