Parasitology: 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

Sample item

A teenager who swam in a warm freshwater pond develops severe frontal headache, fever, neck stiffness and rapid deterioration within days. CSF shows motile trophozoites on a wet mount. Which organism is responsible?

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

The answer and the reasoning

C. Naegleria fowleri

Naegleria fowleri causes primary amoebic meningoencephalitis. It enters through the cribriform plate while swimming in warm freshwater, travels along the olfactory nerve and kills rapidly. Motile trophozoites are seen in fresh CSF.

Option by option

  • A. Acanthamoeba castellanii

    Acanthamoeba causes subacute granulomatous encephalitis in immunocompromised hosts and keratitis in lens wearers.

  • B. Toxoplasma gondii

    Toxoplasma is an intracellular protozoan causing ring-enhancing lesions in the immunocompromised.

  • C. Naegleria fowleri (correct)

    Correct. Warm freshwater exposure and fulminant meningitis with motile amoebae suggest Naegleria.

  • D. Entamoeba histolytica

    Entamoeba histolytica causes colitis and liver abscess.

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.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is C, Naegleria fowleri. Naegleria fowleri causes primary amoebic meningoencephalitis.

Why is "Acanthamoeba castellanii" not the answer?

Acanthamoeba causes subacute granulomatous encephalitis in immunocompromised hosts and keratitis in lens wearers.

Why is "Toxoplasma gondii" not the answer?

Toxoplasma is an intracellular protozoan causing ring-enhancing lesions in the immunocompromised.

Why is "Entamoeba histolytica" not the answer?

Entamoeba histolytica causes colitis and liver abscess.

What concept does this question test?

It tests Parasitology in Microbiology. It enters through the cribriform plate while swimming in warm freshwater, travels along the olfactory nerve and kills rapidly. Motile trophozoites are seen in fresh CSF.

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?

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.