Communicable diseases: post-kala-azar dermal leishmaniasis: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Communicable diseases: post-kala-azar dermal leishmaniasis

Sample item

In a kala-azar elimination programme, a 25-year-old man treated for visceral leishmaniasis two years ago now has hypopigmented macules and nodules on the face. He has no fever and no splenomegaly. Why is it important to detect and treat him?

AHe can act as a reservoir that sustains transmission to sandfliesBHis stool carries the parasite into water suppliesCHe is at high risk of relapsing visceral disease within weeksDHis skin lesions transmit infection by direct contact

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. He can act as a reservoir that sustains transmission to sandflies

Post-kala-azar dermal leishmaniasis (PKDL) develops after treated visceral leishmaniasis and the skin lesions harbour parasites. In India humans are the main reservoir, so PKDL cases can infect sandflies and maintain transmission between epidemics, which is why finding and treating them is part of elimination.

Option by option

A. He can act as a reservoir that sustains transmission to sandflies (correct)
Correct. Parasites in the skin lesions infect sandflies, so he keeps the cycle going.
B. His stool carries the parasite into water supplies
Leishmania does not spread by the faeco-oral route.
C. He is at high risk of relapsing visceral disease within weeks
PKDL does not signal imminent relapse of visceral disease, and he has no fever or splenomegaly.
D. His skin lesions transmit infection by direct contact
Leishmania is transmitted by the bite of sandflies and not by direct skin contact.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this PSM question

What is the answer to this PSM question?

The best answer is A, He can act as a reservoir that sustains transmission to sandflies. Post-kala-azar dermal leishmaniasis (PKDL) develops after treated visceral leishmaniasis and the skin lesions harbour parasites.

Why is "His stool carries the parasite into water supplies" not the answer?

Leishmania does not spread by the faeco-oral route.

Why is "He is at high risk of relapsing visceral disease within weeks" not the answer?

PKDL does not signal imminent relapse of visceral disease, and he has no fever or splenomegaly.

Why is "His skin lesions transmit infection by direct contact" not the answer?

Leishmania is transmitted by the bite of sandflies and not by direct skin contact.

What concept does this question test?

It tests Communicable diseases: post-kala-azar dermal leishmaniasis in PSM. In India humans are the main reservoir, so PKDL cases can infect sandflies and maintain transmission between epidemics, which is why finding and treating them is part of elimination.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Communicable diseases: post-kala-azar dermal leishmaniasis?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.