Parasitology: unfertilised Ascaris egg: 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: unfertilised Ascaris egg

Sample item

Stool microscopy in a child shows elongated oval eggs with a thin shell, a scanty irregular outer coat and a mass of refractile granules inside. What is the correct interpretation?

AFasciola egg suggesting watercress ingestionBImmature hookworm egg that will hatch in the gutCUnfertilised Ascaris egg, so only female worms are presentDFertilised Ascaris egg that is immediately infective

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

The answer and the reasoning

C. Unfertilised Ascaris egg, so only female worms are present

Unfertilised Ascaris eggs are longer and narrower than fertilised ones, with a thin shell and internal refractile granules instead of a developing embryo. They are found when only female worms are present and they are not infective.

Option by option

A. Fasciola egg suggesting watercress ingestion
Fasciola eggs are very large and operculated.
B. Immature hookworm egg that will hatch in the gut
Hookworm eggs are thin-shelled ovals with a clear space and early cleavage cells, not granular contents.
C. Unfertilised Ascaris egg, so only female worms are present (correct)
Correct. Elongated granular eggs indicate unfertilised eggs from female-only infection.
D. Fertilised Ascaris egg that is immediately infective
Fertilised eggs are rounded, with a thick mamillated shell, and need days in soil to become infective.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is C, Unfertilised Ascaris egg, so only female worms are present. Unfertilised Ascaris eggs are longer and narrower than fertilised ones, with a thin shell and internal refractile granules instead of a developing embryo.

Why is "Fasciola egg suggesting watercress ingestion" not the answer?

Fasciola eggs are very large and operculated.

Why is "Immature hookworm egg that will hatch in the gut" not the answer?

Hookworm eggs are thin-shelled ovals with a clear space and early cleavage cells, not granular contents.

Why is "Fertilised Ascaris egg that is immediately infective" not the answer?

Fertilised eggs are rounded, with a thick mamillated shell, and need days in soil to become infective.

What concept does this question test?

It tests Parasitology: unfertilised Ascaris egg in Microbiology. They are found when only female worms are present and they are not infective.

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 Parasitology: unfertilised Ascaris egg?

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.