Herpes – Zoster is caused by –
**Core Concept**
Herpes-Zoster, also known as shingles, is a viral infection caused by the reactivation of latent varicella-zoster virus (VZV). This virus initially infects individuals during childhood, causing chickenpox, and remains dormant in the dorsal root ganglia until it re-emerges years later.
**Why the Correct Answer is Right**
The correct answer is the varicella-zoster virus (VZV), which is a type of herpesvirus. When VZV reactivates, it travels along the nerve fibers and causes a painful rash, typically on one side of the body. This reactivation is thought to occur due to a decline in cell-mediated immunity with age, allowing the latent virus to reactivate.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a virus that causes Herpes-Zoster. Herpes Simplex Virus (HSV) is a different type of herpesvirus that causes oral and genital herpes.
**Option B:** This option is incorrect because it is not directly related to the causation of Herpes-Zoster. Human Papillomavirus (HPV) is a different virus that causes various types of skin and mucous membrane lesions.
**Option C:** This option is incorrect because it is not the correct virus that causes Herpes-Zoster. Cytomegalovirus (CMV) is another type of herpesvirus that can cause various infections, but it is not the primary cause of Herpes-Zoster.
**Clinical Pearl / High-Yield Fact**
Herpes-Zoster is more common in individuals with weakened immune systems, such as those with HIV/AIDS or taking immunosuppressive medications. It is also more common in older adults, as cell-mediated immunity declines with age.
**Correct Answer: D. Varicella-Zoster Virus**