Huge, up to 450 nm long with a complex capsid symmetry. The poxviruses are subdivided into genera which differ in external structure by em.

Poxviruses survive for years in dust.

Up to 30 different structural proteins.

Nonstructural proteins include viral epidermal growth factor (see later) and viral DNA and RNA polymerases to allow intracytoplasmic replication within obvious inclusion bodies (see later).