Which of the following is a DNA Virus?

Appeared in: UP CHO - 2018

Explanation

Hepatitis B virus (HBV) is the only human hepatitis virus with a DNA genome.
It belongs to the Hepadnaviridae family and possesses a unique, partially double-stranded circular DNA.
Its replication cycle is distinct from other DNA viruses as it uses a reverse transcriptase enzyme, a feature more commonly associated with retroviruses (which are RNA viruses).
All other major human hepatitis viruses (A, C, D, and E) are RNA viruses.

Option A: Hepatitis A virus (HAV) is an RNA virus. It belongs to the Picornaviridae family and has a single-stranded RNA (ssRNA) genome.
Option C: Hepatitis C virus (HCV) is an RNA virus. It is a member of the Flaviviridae family and has a single-stranded RNA (ssRNA) genome.
Option D: Hepatitis D virus (HDV), or the delta agent, is a defective RNA virus. It has a circular single-stranded RNA (ssRNA) genome and is unique because it requires the Hepatitis B virus surface antigen (HBsAg) for its own replication and transmission.

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 their genetic material (DNA vs. RNA) as background academic context rather than a clinical decision trigger.
Knowing the genetic makeup (DNA vs. RNA) of hepatitis viruses is crucial for diagnosis (using DNA or RNA-based tests like PCR) and treatment, as antiviral medications target specific viral replication pathways.
The HBV vaccine, which prevents infection from a DNA virus, also indirectly protects against the RNA-based Hepatitis D virus (HDV), as HDV cannot replicate without a concurrent HBV infection.
What if? If a patient is a chronic carrier of Hepatitis B (a DNA virus), they are at a higher risk for developing hepatocellular carcinoma and also for being superinfected with Hepatitis D (an RNA virus), which often leads to more severe, fulminant liver disease.

How to Approach the Question

This is a factual recall question from microbiology.
The question asks you to identify the DNA virus from the list of hepatitis viruses.
First, recall the basic classification of the main hepatitis viruses (A, B, C, D, E) based on their nucleic acid (genetic material).
Remember that most are RNA viruses.
Identify the exception in the group. Hepatitis B virus (HBV) is the only one that is a DNA virus.
Scan the options and select the one corresponding to Hepatitis B.

Concept Tested & Keywords

Concept Tested: Classification of hepatitis viruses based on their genetic material (DNA vs. RNA).
Stem keywords: DNA Virus, Hepatitis
Lead-in keywords: Which

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

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

E6 Microbiology Essentials Sastry 4e Part 2 p. 41-43

Practise the full UP CHO - 2018

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