Outbreak investigation: 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 · Outbreak investigation

Sample item

What epidemic-curve pattern most suggests a single point-source exposure?

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

The answer and the reasoning

A. Cases cluster within one incubation period

A point-source outbreak often produces a sharp cluster of cases within roughly one incubation period because people were exposed to the same source during a limited time window.

Option by option

  • A. Cases cluster within one incubation period (correct)

    Correct: tight clustering within one incubation period suggests a point source.

  • B. Cases rise in regular waves over many generations

    Repeated waves suggest propagated person-to-person transmission.

  • C. No cases occur after exposure

    An outbreak requires cases, so no cases cannot define one.

  • D. Cases occur at a constant low baseline only

    A stable baseline does not describe an acute outbreak cluster.

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 PSM question

What is the answer to this PSM question?

The best answer is A, Cases cluster within one incubation period. A point-source outbreak often produces a sharp cluster of cases within roughly one incubation period because people were exposed to the same source during a limited time window.

Why is "Cases rise in regular waves over many generations" not the answer?

Repeated waves suggest propagated person-to-person transmission.

Why is "No cases occur after exposure" not the answer?

An outbreak requires cases, so no cases cannot define one.

Why is "Cases occur at a constant low baseline only" not the answer?

A stable baseline does not describe an acute outbreak cluster.

What concept does this question test?

It tests Outbreak investigation in PSM. The correct option holds because: Correct: tight clustering within one incubation period suggests a point source.

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 Outbreak investigation?

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.