Communicable diseases: dracunculiasis intermediate host: 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 · Communicable diseases: dracunculiasis intermediate host

Sample item

In a village that depends on an open step-well, several adults develop a painful blister on the foot from which a long thread-like worm later emerges when the foot is dipped in water. Which organism in the water is the intermediate host of this parasite?

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

The answer and the reasoning

B. Cyclops (water flea)

Guinea worm (Dracunculus medinensis) larvae released from the blister are eaten by Cyclops, a tiny crustacean, and humans are infected by drinking water containing infected Cyclops. Control relies on safe drinking water, filtering water through fine cloth and keeping patients out of water sources. India has been certified free of the disease.

Option by option

  • A. Culex larva

    Culex larvae are involved in the breeding of vectors of filariasis and do not host the guinea worm.

  • B. Cyclops (water flea) (correct)

    Correct. Cyclops carries the infective larval stage and is swallowed with unfiltered water.

  • C. Freshwater snail

    Freshwater snails are intermediate hosts of schistosomes and not of the guinea worm.

  • D. Sandfly larva

    Sandflies transmit leishmaniasis and are unrelated to this infection.

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.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, Cyclops (water flea). Guinea worm (Dracunculus medinensis) larvae released from the blister are eaten by Cyclops, a tiny crustacean, and humans are infected by drinking water containing infected Cyclops.

Why is "Culex larva" not the answer?

Culex larvae are involved in the breeding of vectors of filariasis and do not host the guinea worm.

Why is "Freshwater snail" not the answer?

Freshwater snails are intermediate hosts of schistosomes and not of the guinea worm.

Why is "Sandfly larva" not the answer?

Sandflies transmit leishmaniasis and are unrelated to this infection.

What concept does this question test?

It tests Communicable diseases: dracunculiasis intermediate host in PSM. Control relies on safe drinking water, filtering water through fine cloth and keeping patients out of water sources. India has been certified free of the disease.

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 Communicable diseases: dracunculiasis intermediate host?

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.