Yaws

Yaws is a chronic non-venereal treponemal infection caused by Treponema pallidum subspecies pertenue, affecting skin, bone, and cartilage, mainly in children in tropical communities.

• Endemic in the Pacific (Papua New Guinea, Solomon Islands, Vanuatu), West Africa (Ghana, Cote d'Ivoire), Central Africa, and Southeast Asia (Indonesia, Timor-Leste).
• Spread by direct skin contact with exudative lesions; most cases occur in children aged 2 to 15 years in poor, remote, overcrowded settings.
• Targeted for eradication through mass azithromycin treatment.

• Primary: "mother yaw", a papilloma or ulcer (strawberry like) at the inoculation site, with regional adenopathy, lasting weeks to months.
• Secondary: multiple papillomas, painful palmoplantar hyperkeratosis ("crab yaws"), bone and joint pain, periostitis (dactylitis, saber shins), and generalised skin lesions.
• Latent phase asymptomatic (serological) with relapses.
• Tertiary (10 to 15%, after 5 or more years): destructive gummata, hyperkeratosis, and gangosa (nasopharyngeal destruction), disfiguring bone changes.

• Clinical diagnosis in endemic areas, with serology: rapid treponemal tests (point-of-care) and non-treponemal tests (RPR or VDRL; titre of at least 1:8 indicates active disease).
• Dual treponemal/non-treponemal point-of-care test (DPP) identifies active infection.
• PCR on lesion swabs (identifies T. pallidum pertenue and azithromycin resistance mutations in 23S rRNA).
• Exclude cutaneous leishmaniasis, scabies, tinea, impetigo, tropical ulcer, venereal syphilis, and warts.
• Radiographs for bone changes.

• First line: single oral dose of azithromycin 30 mg/kg (maximum 2 g).
• Alternative: benzathine penicillin G single IM injection, 1.2 million units for adults and children aged 10 years and above, or 0.6 million units for children under 10.
• Total community treatment (mass drug administration with azithromycin 30 mg/kg) when prevalence is high; total targeted treatment of contacts.
• Follow up with repeat serology at 6 and 12 months; retreat if RPR titre does not fall fourfold or relapse; test for macrolide resistance.
• Wound care and treatment of secondary bacterial infection; hygiene, water, and sanitation.