Parasitology: Romana sign in Chagas disease: practice question

A Microbiology 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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Microbiology · Parasitology: Romana sign in Chagas disease

Sample item

A 4-year-old child from a mud-walled house in rural Brazil has fever, unilateral painless periorbital oedema, conjunctivitis and a tender preauricular lymph node. The parasite entered through the conjunctiva after contamination with the faeces of a nocturnal bug. What is the organism?

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

The answer and the reasoning

B. Trypanosoma cruzi

Romana sign is unilateral painless eyelid swelling with conjunctivitis at the site of entry of Trypanosoma cruzi, when infected reduviid bug faeces are rubbed into the eye. It marks acute Chagas disease.

Option by option

  • A. Loa loa

    Loa loa causes transient Calabar swellings and an eye worm, transmitted by Chrysops flies and not by bug faeces.

  • B. Trypanosoma cruzi (correct)

    Correct. Romana sign is the classic portal-of-entry sign of acute Chagas disease.

  • C. Onchocerca volvulus

    Onchocerca volvulus is transmitted by blackfly bites and causes nodules and dermatitis.

  • D. Trypanosoma brucei gambiense

    T. brucei is transmitted by tsetse bite and is restricted to Africa.

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.

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Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Trypanosoma cruzi. Romana sign is unilateral painless eyelid swelling with conjunctivitis at the site of entry of Trypanosoma cruzi, when infected reduviid bug faeces are rubbed into the eye.

Why is "Loa loa" not the answer?

Loa loa causes transient Calabar swellings and an eye worm, transmitted by Chrysops flies and not by bug faeces.

Why is "Onchocerca volvulus" not the answer?

Onchocerca volvulus is transmitted by blackfly bites and causes nodules and dermatitis.

Why is "Trypanosoma brucei gambiense" not the answer?

T. brucei is transmitted by tsetse bite and is restricted to Africa.

What concept does this question test?

It tests Parasitology: Romana sign in Chagas disease in Microbiology. It marks acute Chagas disease.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Parasitology: Romana sign in Chagas disease?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.