Causative agent of Infectious mononucleosis
**Core Concept**
Infectious mononucleosis, also known as "mono" or the "kissing disease," is primarily caused by a viral infection. The **Epstein-Barr virus (EBV)** is the most common causative agent of this condition. EBV is a member of the **Herpesviridae** family.
**Why the Correct Answer is Right**
The correct answer is right because EBV is transmitted through saliva, mucus, and other bodily fluids, leading to infection of **B lymphocytes**. This infection results in the production of **atypical lymphocytes**, a hallmark of infectious mononucleosis. The virus infects **B cells** by binding to the **CD21 receptor**.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not specified, but other viruses like CMV can cause similar symptoms, not typically classified under infectious mononucleosis.
**Option B:** Incorrect as it is not provided, but typically, other herpesviruses are not the primary cause.
**Option C:** Incorrect, not given, but usually, this would be another incorrect pathogen.
**Option D:** Incorrect, not specified, but likely another incorrect viral agent.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that EBV infection can lead to **Burkitt lymphoma** and **nasopharyngeal carcinoma** in rare cases, making it a significant public health concern.
**Correct Answer:** D. Epstein-Barr virus