Parasitology: Giardia lamblia: practice question

A Microbiology 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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Microbiology · Parasitology: Giardia lamblia

Sample item

A 6-year-old child has several weeks of foul-smelling greasy stools, bloating and weight loss, without fever or blood in stool. Stool microscopy shows pear-shaped binucleate trophozoites with a sucking disc. Which is the drug of choice?

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

The answer and the reasoning

B. Tinidazole

Giardia lamblia colonises the duodenum and jejunum, impairing absorption and producing steatorrhoea without invasion. It is acquired from faecally contaminated water through cysts. Treatment is with a nitroimidazole such as tinidazole (single dose), metronidazole or secnidazole, and nitazoxanide is an alternative.

Option by option

  • A. Praziquantel

    Praziquantel treats cestodes and trematodes, not flagellates.

  • B. Tinidazole (correct)

    Correct. Nitroimidazoles are effective against Giardia trophozoites.

  • C. Ivermectin

    Ivermectin treats strongyloidiasis, onchocerciasis and scabies.

  • D. Albendazole

    Albendazole is used for roundworms and hookworms and is not first-line for Giardia.

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 Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Tinidazole. Giardia lamblia colonises the duodenum and jejunum, impairing absorption and producing steatorrhoea without invasion.

Why is "Praziquantel" not the answer?

Praziquantel treats cestodes and trematodes, not flagellates.

Why is "Ivermectin" not the answer?

Ivermectin treats strongyloidiasis, onchocerciasis and scabies.

Why is "Albendazole" not the answer?

Albendazole is used for roundworms and hookworms and is not first-line for Giardia.

What concept does this question test?

It tests Parasitology: Giardia lamblia in Microbiology. It is acquired from faecally contaminated water through cysts. Treatment is with a nitroimidazole such as tinidazole (single dose), metronidazole or secnidazole, and nitazoxanide is an alternative.

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 Parasitology: Giardia lamblia?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.