Which of the following hepatitis viruses is classified as a DNA virus?

RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Applied Microbiology & Infection control

Easy

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

Hepatitis B virus (HBV) is the correct answer as it is the only major human hepatitis virus with a DNA genome.
It belongs to the Hepadnaviridae family and has a unique, partially double-stranded circular DNA (dsDNA) genome.
While it is a DNA virus, it replicates using an RNA intermediate via a process called reverse transcription, a feature it shares with retroviruses.

Option A: Hepatitis A virus (HAV) is incorrect because it is a single-stranded RNA (ssRNA) virus belonging to the Picornaviridae family.
Option C: Hepatitis C virus (HCV) is incorrect. It is a single-stranded RNA (ssRNA) virus from the Flaviviridae family.
Option D: Hepatitis E virus (HEV) is incorrect. It is a single-stranded RNA (ssRNA) virus from the Hepeviridae family.

Visual 1: Table: Comparison of Human Hepatitis Viruses (A, B, C, D, E) - A summary table showing the virus family, genome type (RNA/DNA), transmission routes, and potential for chronic infection for each hepatitis virus.
Visual 2: Diagram: Structure of Hepatitis B Virus (Dane Particle) - A labeled diagram showing the outer envelope (HBsAg), the inner core (HBcAg), and the partially double-stranded DNA 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 based on genome type (DNA vs. RNA) as background academic context rather than a clinical decision trigger.
For nurses, knowing HBV is a DNA virus is key to understanding its persistence and the mechanism of action for antiviral therapies. It also reinforces the importance of vaccination as the primary prevention strategy.
The presence of HBV DNA in a patient's blood is a direct measure of active viral replication and infectivity. This guides nursing care regarding transmission-based precautions and patient education on preventing spread.
What if? If a nurse sustains a needlestick injury from a patient with chronic Hepatitis B, the protocol involves immediate post-exposure prophylaxis (PEP). This includes both the Hepatitis B vaccine and Hepatitis B Immune Globulin (HBIG) to provide passive and active immunity, highlighting the serious risk of this DNA virus.

How to Approach the Question

This is a factual recall question testing fundamental knowledge of virology.
First, identify the key concepts in the question stem: 'hepatitis viruses' and 'DNA virus'.
Systematically review the options provided: Hepatitis A, B, C, and E.
Recall the genomic classification of each virus. A helpful mnemonic is that 'B' is the 'body' of the DNA viruses among the main hepatitis types, while the others are RNA viruses.
Select Hepatitis B as the only DNA virus from the list. The others (A, C, E, and also D) are all RNA viruses.

Concept Tested & Keywords

Concept Tested: Classification of hepatitis viruses based on genome type (DNA vs. RNA)
Stem keywords: hepatitis viruses, DNA virus
Lead-in keywords: Which
Negative lead-in flag: false

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