Virology: cytopathic effect: 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 · Virology: cytopathic effect

Sample item

A nasopharyngeal aspirate from an infant with bronchiolitis is inoculated onto HEp-2 cells. After several days, the monolayer shows multinucleated giant cells and syncytia. Which virus is most likely?

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

The answer and the reasoning

D. Respiratory syncytial virus

Respiratory syncytial virus, a paramyxovirus, is named for the syncytia that its fusion protein produces in cell culture. Infection typically causes bronchiolitis in infants. Rhinoviruses cause rounding, adenoviruses cause grape-like clusters, and influenza virus is detected by haemadsorption.

Option by option

  • A. Adenovirus

    Adenovirus produces grape-like clusters of rounded cells.

  • B. Influenza A virus

    Influenza virus produces little cytopathic effect and is detected by haemadsorption.

  • C. Rhinovirus

    Rhinovirus causes rounding of cells, not syncytia.

  • D. Respiratory syncytial virus (correct)

    Correct. Syncytium formation is the cytopathic effect of respiratory syncytial virus.

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 D, Respiratory syncytial virus. Respiratory syncytial virus, a paramyxovirus, is named for the syncytia that its fusion protein produces in cell culture.

Why is "Adenovirus" not the answer?

Adenovirus produces grape-like clusters of rounded cells.

Why is "Influenza A virus" not the answer?

Influenza virus produces little cytopathic effect and is detected by haemadsorption.

Why is "Rhinovirus" not the answer?

Rhinovirus causes rounding of cells, not syncytia.

What concept does this question test?

It tests Virology: cytopathic effect in Microbiology. Infection typically causes bronchiolitis in infants. Rhinoviruses cause rounding, adenoviruses cause grape-like clusters, and influenza virus is detected by haemadsorption.

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 Virology: cytopathic effect?

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.