Which one of the following is a disease caused by viruses with DNA Genome ?

Question

Accepted Answer

The correct option is 4: Chicken Pox

Chicken Pox, clinically known as varicella, is the correct answer because it is caused by the Varicella-Zoster Virus (VZV), which belongs to the Herpesviridae family, specifically the genus *Varicellovirus*. A defining characteristic of the entire Herpesviridae family, including VZV, is that their genetic material consists of a large, linear **double-stranded DNA (dsDNA) genome**. The virus uses this DNA genome for replication within the host cell's nucleus, a process typical of all DNA viruses except Parvovirus. This feature distinguishes VZV from the viruses causing the other diseases listed in the options, all of which use an RNA genome. After causing the primary infection (chickenpox), VZV has the unique ability to establish latency in the sensory nerve ganglia, and its dsDNA genome allows it to remain dormant before potentially reactivating later in life to cause Shingles (Herpes Zoster).

The incorrect option is 1: Poliomyelitis

Poliomyelitis, or Polio, is a severe infectious disease caused by the Poliovirus. The Poliovirus is a member of the Picornaviridae family and the Enterovirus genus. Picornaviruses are characterized as small, non-enveloped viruses with a **single-stranded RNA genome of positive polarity** (ssRNA(+)). This positive-sense RNA genome functions directly as messenger RNA once inside the host cell and can immediately be translated by host ribosomes to produce viral proteins. Because its genetic material is RNA, not DNA, Poliovirus does not fit the criteria of the question.

The incorrect option is 2: AIDS

Acquired Immunodeficiency Syndrome (AIDS) is the most advanced stage of infection caused by the Human Immunodeficiency Virus (HIV). HIV is classified as a **Retrovirus**. All retroviruses, including HIV, have a genome composed of two identical copies of **single-stranded RNA** and carry the enzyme reverse transcriptase. Upon infecting the host, reverse transcriptase uses the viral RNA template to synthesize a double-stranded DNA copy, which is then integrated into the host cell's genome. However, the genetic material present *inside the infectious viral particle* (virion) is RNA, classifying HIV as an RNA virus.

The incorrect option is 3: Rabies

Rabies is a deadly viral disease of the central nervous system caused by the Rabies virus. This virus belongs to the Rhabdoviridae family, which are distinctively bullet-shaped. Rhabdoviruses possess a non-segmented **single-stranded RNA genome of negative polarity** (ssRNA(-)). This means the viral RNA genome cannot be directly translated by the host cell. Instead, it must first be transcribed by a viral RNA polymerase into a complementary positive-sense RNA strand, which then serves as the mRNA for protein synthesis. Consequently, Rabies is also caused by an RNA virus, making this option incorrect.