Which of the following is a DNA virus?

Appeared in: MP CHO-2020

Explanation

Hepatitis B virus (HBV) is the correct answer as it is a DNA virus, belonging to the hepadnavirus family.
Its genome is a partially double-stranded circular DNA molecule.
This is a distinct feature, as all other major human hepatitis viruses (A, C, D, and E) are RNA viruses.
HBV replicates in the liver using a unique mechanism that involves reverse transcription, a process more typical of retroviruses.

Option A: Hepatitis A virus (HAV) is an RNA virus, not a DNA virus. It belongs to the Picornaviridae family and has a single-stranded RNA genome.
Option C: Hepatitis C virus (HCV) is an RNA virus, belonging to the Flaviviridae family. It has a single-stranded RNA genome.
Option D: Hepatitis D virus (HDV), or the delta agent, is a defective RNA virus. It has a circular single-stranded RNA genome.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Hepatitis Viruses (DNA vs. RNA) as background academic context rather than a clinical decision trigger.
Knowing the genetic makeup (DNA vs. RNA) is fundamental to understanding the pathophysiology, treatment, and prevention of viral hepatitis.
The HBV vaccine is crucial because it not only prevents Hepatitis B infection but also, by extension, prevents Hepatitis D, as HDV cannot infect a person without the presence of HBV.
Antiviral therapies are designed to target specific viral components and replication cycles. For example, treatments for HBV target its DNA polymerase and reverse transcriptase activity.

How to Approach the Question

Identify the core of the question: It asks to identify the DNA virus from a list of hepatitis viruses.
This is a factual recall question. Access your knowledge about the classification of pathogens.
Recall the genetic material for each type of hepatitis virus: A, C, D, and E are RNA viruses.
Remember the exception: Hepatitis B is the only DNA virus in this group.
Select the option corresponding to Hepatitis B.
A useful mnemonic is to remember that 'B' is the odd one out in the 'A, B, C, D' sequence when it comes to viral genome type.

Concept Tested & Keywords

QbT5RD5Q2jgisgKKYRT1Ua

E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 158-160

E6 Medicine Harrison 22e Part 2 p. 547-549

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 837-839

Practise the full MP CHO-2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.