**Question:** Which virus remains dormant but can be reactivated is -

A. Herpes Simplex Virus (HSV)
B. Varicella-Zoster Virus (VZV)
C. Human Immunodeficiency Virus (HIV)
D. Hepatitis B Virus (HBV)

**Core Concept:** Understanding the concept of latent infections and virus dormancy is crucial for understanding the pathophysiology of certain diseases. Latent infections occur when viruses establish a persistent infection without causing clinical symptoms. These viruses can be reactivated under specific conditions, leading to disease manifestation.

**Why the Correct Answer is Right:**

The correct answer, B. Varicella-Zoster Virus (VZV), is a DNA virus that causes chickenpox (primary infection) and subsequently establishes latency in the dorsal root ganglia (nerve cells). VZV remains dormant until triggered by factors such as immune system suppression, stress, or other opportunistic infections. Reactivation results in herpes zoster (shingles), a painful rash with characteristic blisters.

**Why Each Wrong Option is Incorrect:**

A. Herpes Simplex Virus (HSV) is another DNA virus that causes two primary infections: HSV-1 for oral herpes (cold sores) and HSV-2 for genital herpes. Unlike VZV, HSV does not establish a latent infection but remains latent in neurons. Reactivation results in recurrent herpes lesions.

C. Human Immunodeficiency Virus (HIV) is a lentivirus that primarily targets CD4+ T cells, leading to acquired immune deficiency syndrome (AIDS). HIV does not establish a latent infection; instead, it progressively destroys immune cells, making the host more susceptible to opportunistic infections.

D. Hepatitis B Virus (HBV) is an RNA virus responsible for chronic hepatitis and liver cirrhosis. Unlike the selected answer, HBV does not establish latency but can cause lifelong infection with complications.

**Clinical Pearl:** Understanding viral latency and reactivation is essential for diagnosing and treating patients with recurrent viral infections. Latent infections can lead to lifelong disease burden and complications. It is crucial to consider these factors when assessing patients with recurrent symptoms or chronic disease conditions.