The Herpesviridae, a large family of DNA viruses, causes disease in animals and humans. Members of this family are known as herpesviruses. They all share a common structure where they are composed of relatively large double-stranded, linear DNA genomes encoding 100-200 genes encased within an icosahedral protein cage called the capsid. The whole particle is known as a virion. They are all nuclear-replicating.

When a viral particle contacts a cell with specific types of receptor molecules on the cell surface an infection happens. Eventually viral DNA migrates to the cell nucleus and starts to replicate there. Infected cells transcribe lytic viral genes. The virus can persist in the cell indefinitely. Primary infection is accompanied by self-limited period clinical illness while long term latency is symptom-free. Lytic activation leads to cell death and is often accompanied by emergence of non-specific symptoms such as low grade fever, headache, sore throat, malaise, and rash as well as clinical signs such as a swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells.

Herpesviruses are known to establish lifelong infections often through immune evasion. It does this by encoding a protein mimicking human interleukin 10. It can also invade the immune system through down regulation of MHC I and MHC II. This is in almost every human herpesvirus.