**Question:** The following are true about EBV except -

A. Epstein-Barr virus (EBV) is a member of the Herpesviridae family.
B. EBV infection primarily affects children.
C. EBV infection is associated with infectious mononucleosis (glandular fever).
D. EBV infection can cause chronic active infection in immunocompromised patients.

**Correct Answer:** B. EBV infection primarily affects children.

**Core Concept:**
Epstein-Barr virus (EBV) is a member of the Herpesviridae family, a group of viruses known for their ability to establish lifelong latent infections in their human hosts. Unlike some other herpesviruses, EBV primarily infects B cells, a type of white blood cell involved in the immune response.

**Why the Correct Answer is Right:**
EBV primarily affects immunocompetent individuals, meaning it primarily infects and establishes latency in individuals with a robust immune system. This allows the virus to coexist within the host without causing overt disease. In contrast, children generally have a less developed immune system compared to adults, making them more prone to severe illnesses like infectious mononucleosis (IM) when infected with EBV.

**Why Each Wrong Option is Incorrect:**

A. EBV is a member of the Herpesviridae family, but its primary mode of infection and clinical manifestations are different from those of herpes simplex virus (HSV) and varicella-zoster virus (VZV), which primarily affect infants and children.

C. EBV primarily infects B cells and establishes latency, which is essential for its persistence in the host. Infectious mononucleosis (IM) is a clinical syndrome associated with EBV infection, but it primarily affects immunocompetent individuals. Children are more likely to experience severe IM due to their less developed immune system.

D. Chronic active EBV infection can occur in immunocompromised patients, where the immune system is unable to control the virus. However, this is not the primary mode of EBV infection or clinical presentation. EBV primarily infects B cells and establishes latency, resulting in clinical syndromes like infectious mononucleosis (IM) or post-transplant lymphoproliferative disorders (PTLD). While EBV infection can cause chronic active infection in immunocompromised patients, this is not the primary mode of infection or clinical presentation in healthy adults.

**Clinical Pearl:**
Infectious mononucleosis (IM) is a clinical syndrome associated with EBV infection, which primarily affects immunocompetent individuals. Children are more susceptible to severe IM due to their less developed immune system. This highlights the importance of a robust immune system in managing EBV infection and preventing severe complications.