Virology: hepatitis D: 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 · Virology: hepatitis D

Sample item

A chronic HBsAg carrier abruptly develops severe hepatitis. Testing shows anti-HDV IgM positive. Why can the delta agent cause infection in this patient?

AIt encodes its own envelope glycoprotein and needs no helperBIt is a defective RNA virus that uses HBsAg as its envelopeCIt is a prion that depends on hepatitis B core proteinDIt is a DNA virus that integrates into the hepatocyte genome

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

The answer and the reasoning

B. It is a defective RNA virus that uses HBsAg as its envelope

Hepatitis D virus has a small circular single-stranded RNA genome and lacks its own envelope protein. It depends on HBsAg from hepatitis B virus to assemble infectious virions, so it only infects people with HBV, either as coinfection or superinfection. Superinfection of a carrier often causes severe or fulminant disease and progression to chronicity.

Option by option

A. It encodes its own envelope glycoprotein and needs no helper
Delta virus has no envelope protein of its own and requires hepatitis B.
B. It is a defective RNA virus that uses HBsAg as its envelope (correct)
Correct. Delta virus is dependent on HBsAg for its coat.
C. It is a prion that depends on hepatitis B core protein
Delta agent is a virus with an RNA genome and not a prion.
D. It is a DNA virus that integrates into the hepatocyte genome
Delta virus has an RNA genome and does not integrate as a DNA virus.

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.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, It is a defective RNA virus that uses HBsAg as its envelope. Hepatitis D virus has a small circular single-stranded RNA genome and lacks its own envelope protein.

Why is "It encodes its own envelope glycoprotein and needs no helper" not the answer?

Delta virus has no envelope protein of its own and requires hepatitis B.

Why is "It is a prion that depends on hepatitis B core protein" not the answer?

Delta agent is a virus with an RNA genome and not a prion.

Why is "It is a DNA virus that integrates into the hepatocyte genome" not the answer?

Delta virus has an RNA genome and does not integrate as a DNA virus.

What concept does this question test?

It tests Virology: hepatitis D in Microbiology. It depends on HBsAg from hepatitis B virus to assemble infectious virions, so it only infects people with HBV, either as coinfection or superinfection. Superinfection of a carrier often causes severe or fulminant disease and progression to chronicity.

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 Virology: hepatitis D?

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.