EpsteinBarr

Epstein-Barr virus (EBV), also known as human herpesvirus 4 (HHV-4), is a ubiquitous member of the herpesviridae family. It is a double-stranded DNA virus that infects humans and is primarily transmitted via saliva, with less common routes including blood and sexual contact. Primary EBV infection typically occurs in childhood or adolescence; in many children it is asymptomatic, while infection in adolescence can cause infectious mononucleosis.

EBV establishes latent infection in B lymphocytes by binding to CD21 (complement receptor 2) and can express different latency programs that enable persistence for the life of the host. The virus can also infect epithelial cells and periodically reactivate, producing a lytic cycle.

Clinical associations include infectious mononucleosis, and EBV is linked to several malignancies such as endemic Burkitt lymphoma, certain cases of Hodgkin lymphoma, nasopharyngeal carcinoma (especially in southern China and parts of Southeast Asia), and post-transplant lymphoproliferative disorder. EBV may contribute to other diseases, but causality varies.

Diagnosis combines serology and molecular testing. EBV-specific antibodies to viral capsid antigen (VCA) and EBV nuclear antigen (EBNA), together with heterophile tests, help distinguish phases of infection; EBV DNA by PCR can quantify active replication. Biopsy and imaging are used to evaluate suspected EBV-associated cancers.

Treatment and prevention: There is no licensed EBV vaccine. Management of infectious mononucleosis is supportive. Antiviral agents are not routinely used for EBV. EBV-associated cancers are treated with standard oncologic regimens; post-transplant lymphoproliferative disorder may respond to rituximab and reduction of immunosuppression.

Epidemiology: EBV infection is highly prevalent; most adults have been exposed. Primary infection typically occurs in childhood; adolescence infection is more likely to be symptomatic. Geographic variation exists in EBV-associated cancers, with high NPC incidence in southern China and other regions.