Mucocutaneous leishmaniasis — DTM&H MCQ

Correct answer: E — Leishmania braziliensis

The correct answer is E, Leishmania braziliensis. This species belongs to the New World Viannia subgenus and is the principal cause of mucocutaneous leishmaniasis (espundia), in which parasites metastasise from a healed primary cutaneous lesion to nasopharyngeal mucosa years later, producing progressive nasal septal and palatal destruction. Bolivia and other Andean/Amazonian countries are recognised endemic foci for L. braziliensis, matching the travel history. The delayed onset, self-healing skin lesion followed years later by mucosal disease, is the classic natural history of L. (Viannia) braziliensis infection and is why any New World cutaneous leishmaniasis caused by Viannia species warrants systemic treatment to prevent this complication. Why the other options are wrong: D. Leishmania donovani: causes visceral leishmaniasis (kala-azar) in the Indian subcontinent and East Africa, with hepatosplenomegaly, pancytopenia and fever, not mucosal destruction, and is not endemic to South America. C. Leishmania major: an Old World species (Middle East, North Africa, Central Asia) causing self-limiting zoonotic cutaneous ulcers; it does not metastasise to mucosal tissue and is geographically inconsistent with Bolivia. B. Leishmania tropica: causes Old World anthroponotic cutaneous leishmaniasis, typically chronic dry lesions in urban Mediterranean, Middle Eastern and South Asian settings, without mucosal spread. A. Leishmania infantum: found in the Mediterranean basin and Latin America, mainly causes visceral leishmaniasis in children and immunosuppressed adults (and occasionally localised cutaneous disease), but it is not the classic cause of espundia. Key point: a South/Central American patient with a healed cutaneous lesion followed years later by destructive nasal or palatal mucosal disease indicates mucocutaneous leishmaniasis from Leishmania (Viannia) braziliensis.

Reference: UK Health Security Agency (UKHSA), Leishmaniasis: guidance on causative species, clinical forms (cutaneous, mucocutaneous, visceral) and geographic distribution, https://researchportal.ukhsa.gov.uk/en/publications/leishmaniasis/