Which of these is NOT a DNA virus?

UPPSC 2022

Applied Microbiology & Infection control

Easy

Appeared in: UPPSC 2022

Explanation

The correct option is Coronavirus because it belongs to the family Coronaviridae, which are enveloped, positive-sense, single-stranded RNA (+ssRNA) viruses.
Viruses are fundamentally classified based on their genetic material. Since the question asks for the virus that is NOT a DNA virus, the correct answer must be an RNA virus.
Coronaviruses, responsible for illnesses ranging from the common cold to severe diseases like COVID-19, are classic examples of RNA viruses.

Option A: Poxvirus is incorrect because it is a DNA virus. It belongs to the Poxviridae family, which are large, complex viruses with a double-stranded DNA (dsDNA) genome.
Option C: Herpesvirus is incorrect because it is a DNA virus. It is part of the Herpesviridae family, characterized by enveloped virions containing a double-stranded DNA (dsDNA) genome.
Option D: Adenovirus is incorrect because it is a DNA virus. It belongs to the Adenoviridae family, which are non-enveloped viruses with a double-stranded DNA (dsDNA) genome.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of viruses based on genetic material (DNA vs. RNA) as background academic context rather than a clinical decision trigger.
Understanding whether a virus is DNA or RNA-based is crucial for developing antiviral therapies, as the replication mechanisms and enzymes (e.g., polymerases) that can be targeted are fundamentally different.
RNA viruses (like Coronavirus and Influenza) tend to have higher mutation rates than DNA viruses because their RNA-dependent RNA polymerases often lack a proofreading mechanism. This leads to rapid evolution, the emergence of new variants, and challenges for long-term vaccine efficacy.
What if? If a new pandemic were caused by a large DNA virus instead of an RNA virus like SARS-CoV-2, scientists might expect a slower rate of significant variant emergence. This could potentially make the development of long-lasting vaccines and treatments more straightforward.

How to Approach the Question

First, analyze the question to identify the keyword. The word "NOT" is critical here; you are looking for the option that does not fit the category of 'DNA virus'.
Next, recall the primary method of classifying viruses, which is based on their genetic material: DNA or RNA.
Systematically evaluate each option based on this classification. Access your knowledge of common medically important viruses.
Poxvirus (smallpox), Herpesvirus (cold sores, chickenpox), and Adenovirus (common cold, conjunctivitis) are all classic examples of DNA viruses.
Coronavirus, famous for causing diseases like the common cold, SARS, MERS, and COVID-19, is a well-known RNA virus.
By identifying that Coronavirus is the only RNA virus in the list, you can confidently select it as the answer that is NOT a DNA virus.

Concept Tested & Keywords

Concept Tested: Classification of viruses based on genetic material (DNA vs. RNA)
Stem keywords: DNA virus, Poxvirus, Corona virus, Herpesvirus, Adenovirus
Lead-in keywords: NOT
Negative lead-in flag: The question asks to identify the virus that is NOT a DNA virus.

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