National programmes: malaria indicators: 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 · National programmes: malaria indicators

Sample item

In a malaria-endemic block with a population of 40,000, 8,000 blood slides were examined in a year and 200 were confirmed positive for malaria parasites. What is the annual parasite incidence?

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

The answer and the reasoning

B. 5 per 1000 population

Annual parasite incidence is the number of confirmed cases in a year per 1000 population: 200 divided by 40,000, multiplied by 1000, is 5. The slide positivity rate is 200 divided by 8,000, which is 2.5 percent. The annual blood examination rate is 8,000 divided by 40,000, which is 20 per 100 population.

Option by option

  • A. 2.5 per 1000 population

    2.5 is the slide positivity rate in percent, which uses slides examined as the denominator.

  • B. 5 per 1000 population (correct)

    Correct. 200/40,000 x 1000 = 5 per 1000.

  • C. 50 per 1000 population

    50 results from a decimal error in the calculation.

  • D. 20 per 1000 population

    20 is the annual blood examination rate per 100 population, a measure of surveillance effort.

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 B, 5 per 1000 population. Annual parasite incidence is the number of confirmed cases in a year per 1000 population: 200 divided by 40,000, multiplied by 1000, is 5.

Why is "2.5 per 1000 population" not the answer?

2.5 is the slide positivity rate in percent, which uses slides examined as the denominator.

Why is "50 per 1000 population" not the answer?

50 results from a decimal error in the calculation.

Why is "20 per 1000 population" not the answer?

20 is the annual blood examination rate per 100 population, a measure of surveillance effort.

What concept does this question test?

It tests National programmes: malaria indicators in PSM. The slide positivity rate is 200 divided by 8,000, which is 2.5 percent. The annual blood examination rate is 8,000 divided by 40,000, which is 20 per 100 population.

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 National programmes: malaria indicators?

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.