Viruses within the Herpesviridae family are encapsulated, enveloped, double-stranded DNA viruses, with large coding potentials that have co-evolved with their hosts for the past 200 million years. The Herpesviridae family is further divided into three subfamilies: Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae, which is based upon duration of replication cycle, cell tropism, sites of latency, and species restriction. A total of eight viruses comprising all three subfamily members of the Herpesviridae family are known to infect humans and can establish persistent infections that cannot be completely cleared by the host.