Epidemiology: propagated epidemic: 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 · Epidemiology: propagated epidemic

Sample item

In a village, measles cases occur in successive waves, each beginning roughly 10 to 12 days after the preceding one, with each wave larger than the last. Which type of epidemic does this pattern suggest?

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

The answer and the reasoning

D. Propagated epidemic

Waves separated by about one incubation period, growing in size, show person-to-person spread, as in measles. This is a propagated (progressive) epidemic. A point-source outbreak has a single sharp peak within one incubation period.

Option by option

  • A. Common-source point epidemic

    A point-source epidemic shows one sharp peak after a single exposure.

  • B. Seasonal endemic fluctuation

    Seasonal fluctuation recurs yearly and is not seen as repeated waves over days.

  • C. Continuous common-source epidemic

    A continuous common-source epidemic shows a plateau while exposure continues.

  • D. Propagated epidemic (correct)

    Correct. Successive generations of cases separated by the incubation period mean person-to-person spread.

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 D, Propagated epidemic. Waves separated by about one incubation period, growing in size, show person-to-person spread, as in measles.

Why is "Common-source point epidemic" not the answer?

A point-source epidemic shows one sharp peak after a single exposure.

Why is "Seasonal endemic fluctuation" not the answer?

Seasonal fluctuation recurs yearly and is not seen as repeated waves over days.

Why is "Continuous common-source epidemic" not the answer?

A continuous common-source epidemic shows a plateau while exposure continues.

What concept does this question test?

It tests Epidemiology: propagated epidemic in PSM. This is a propagated (progressive) epidemic. A point-source outbreak has a single sharp peak within one incubation period.

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 Epidemiology: propagated epidemic?

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.