Herpesviridae

Herpesviridae is a diverse family of large, enveloped double-stranded DNA viruses within the order Herpesvirales. They infect a wide range of vertebrates, including humans, and are notable for establishing latent infections that persist for the host’s lifetime and may reactivate to cause recurrent disease. The virions have an icosahedral capsid, a tegument layer, and a lipid envelope, and replicate in the cell nucleus.

The family comprises three subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae. Each subfamily contains multiple genera. In humans, representative pathogens include herpes simplex virus types 1 and 2 in the genus Simplexvirus, varicella-zoster virus in the genus Varicellovirus, cytomegalovirus in the genus Cytomegalovirus, Epstein-Barr virus in the genus Lymphocryptovirus, and Kaposi’s sarcoma-associated herpesvirus in the genus Rhadinovirus.

Biology and latency are hallmarks of the family. Alphaherpesviruses often establish latency in sensory neurons with frequent reactivation; betaherpesviruses tend to persist in cells of the myeloid and vascular systems and reactivate slowly; gammaherpesviruses frequently persist in B cells and related tissues and may contribute to oncogenesis in some contexts.

Transmission and disease vary by member but commonly involve direct contact with secretions or skin lesions, respiratory routes, or vertical transmission. Diagnosis relies on molecular methods such as PCR, serology, or culture. Antiviral therapies, including acyclovir and related nucleoside analogs, are used for active infections; ganciclovir targets CMV. Vaccines exist for varicella and zoster; vaccines for other herpesviruses are in development.