The Herpesviridae family contains
over a 100 species of enveloped DNA viruses that affects humans and animals.
They are characterised by the ability to establish latent infections, enabling
the virus to persist indefinitely within infected hosts and to undergo periodic
activation.
The herpesvirus capsid is icosahedral, composed of 162 capsomeres,
and enclosing the core containing the linear dsDNA genome. The nucleocapsid is
surrounded by the lipid envelope derived from the host cell nuclear membrane.
The envelope carries surface spikes about 8nm long. Between the envelope and
capsid is an amorphous structure called the tegument, containing several
proteins and enzymes which aids in replication. The enveloped virion measures
about 200nm and the naked virion about 100nm in diameter. Herpesviruses
replicate in the host cell nucleus. Like other enveloped viruses, herpesviruses
are susceptible to fat solvents like alcohol, ether, chloroform and bile salts.
They are heat labile and have to be stored at -700C.
