Malaria epidemiology: classification of endemicity: 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 · Malaria epidemiology: classification of endemicity

Sample item

A survey in a malaria-endemic area finds a spleen rate of 82% in children aged 2 to 9 years, while the spleen rate in adults is low. How is the endemicity classified?

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

The answer and the reasoning

A. Holoendemic

Endemicity is graded by the spleen rate in children aged 2 to 9: hypoendemic 0 to 10%, mesoendemic 11 to 50%, hyperendemic 51 to 75% and holoendemic above 75%. In holoendemic areas transmission is intense and perennial, so adults acquire immunity and their spleen rate is low. In hyperendemic areas the spleen rate in adults is also high.

Option by option

  • A. Holoendemic (correct)

    Correct. A childhood spleen rate above 75% with low adult rates is holoendemic.

  • B. Hypoendemic

    Hypoendemic areas have spleen rates of only 0 to 10% in children.

  • C. Mesoendemic

    Mesoendemic areas have spleen rates of 11 to 50% in children.

  • D. Hyperendemic

    Hyperendemic areas have childhood spleen rates of 51 to 75%, with high rates in adults too.

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, Holoendemic. Endemicity is graded by the spleen rate in children aged 2 to 9: hypoendemic 0 to 10%, mesoendemic 11 to 50%, hyperendemic 51 to 75% and holoendemic above 75%.

Why is "Hypoendemic" not the answer?

Hypoendemic areas have spleen rates of only 0 to 10% in children.

Why is "Mesoendemic" not the answer?

Mesoendemic areas have spleen rates of 11 to 50% in children.

Why is "Hyperendemic" not the answer?

Hyperendemic areas have childhood spleen rates of 51 to 75%, with high rates in adults too.

What concept does this question test?

It tests Malaria epidemiology: classification of endemicity in PSM. In holoendemic areas transmission is intense and perennial, so adults acquire immunity and their spleen rate is low. In hyperendemic areas the spleen rate in adults is also high.

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 Malaria epidemiology: classification of endemicity?

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.