Yaws — DTM&H MCQ

Correct answer: C — Single-dose oral azithromycin

The correct answer is C, single-dose oral azithromycin. This scenario describes yaws, caused by Treponema pallidum subspecies pertenue, a non-venereal treponematosis endemic in humid tropical communities and typically affecting children who present with a painless papillomatous (frambesial) skin lesion; clustering among classmates reflects the highly contagious, contact-spread nature of early yaws. Positive treponemal serology in a child with no sexual exposure and a classic papilloma is diagnostic in an endemic setting, and this cross-reacts identically with venereal syphilis serology, so clinical context, not serology, distinguishes them. WHO's yaws eradication (Morges) strategy specifies azithromycin 30 mg/kg (max 2 g) as a single oral dose as the preferred treatment for both individual cases and total community treatment, because it is easy to administer, avoids injections, and supports mass campaigns. Why the other options are wrong: A. Ceftriaxone for suspected typhoid: nothing in the stem (fever, abdominal symptoms, rose spots) suggests enteric fever; the lesion and serology point specifically to a treponemal infection, not Salmonella Typhi. E. Flucloxacillin alone: this covers staphylococcal or streptococcal skin infection but has no activity against Treponema pallidum pertenue, so it would not treat the causative organism. D. Ivermectin mass treatment: ivermectin is used for helminths and scabies (and mass drug administration for onchocerciasis/strongyloidiasis), not for bacterial spirochaetal disease. B. Topical aciclovir for 5 days: aciclovir treats herpesvirus infections; the painless papillomatous ulcer described is not vesicular or herpetic, and topical antivirals have no effect on treponemes. Key point: a painless papillomatous skin lesion with positive treponemal serology in a child from an endemic humid region, clustering with peers, is yaws, and WHO's preferred treatment is single-dose oral azithromycin (30 mg/kg, max 2 g).

Reference: World Health Organization, Yaws: Diagnosis and treatment, https://www.who.int/teams/control-of-neglected-tropical-diseases/yaws/diagnosis-and-treatment