Poxviruses (members of the family<unk>  can infect as a family both vertebrate and invertebrate animals.<unk>  viral particles (virions) are generally enveloped (external enveloped virion- EEV), though the intracellular mature virion (IMV) form of the virus, which contains different envelope, is also infectious.  They vary in their shape depending upon the species but are generally shaped like a brick or as an oval form similar to a rounded brick.  The virion size is around 200 nm in diameter and 300 nm in length and carries its genome in a single, linear, double-stranded segment of DNA.  By comparison, Rhinovirus is 1/10th as large as a typical<unk>  virion. Electron micrographs of Orthopoxvirus and Parapoxvirus Genera, including the smallpox virus, have been collected by the International Committee on Taxonomy of Viruses in their<unk>  picture gallery.
The prototype of poxvirus family is vaccinia virus, which has been used as a successful vaccine to eradicate smallpox virus. Vaccinia virus is also used as an effective tool for foreign protein expression to elicite strong host immune response. Vaccinia virus enters cells mainly by cell fusion, although currently the receptor is not known. Virus contains three classes of genes, early, intermediate and late, that are transcribed by viral RNA polymerase and associated transcription factors. Vaccinia virus replicates its genome in cytoplasm of the infected cells and after late gene expression virion morphogenesis produces IMV that contains envelope, although the origin of the envelope membrane is still unknown. IMV  is transported to Golgi to be wrapped additional two membrane to become intracellular enveloped virus (IEV). IEV transports along microtubules to reach cell periphery and fuse with plasma membrane to become cell-associated enveloped virus (CEV) that triggers actin tails on cell surfaces or is releared as EEV.
The name of the family,<unk> , is a legacy of the original grouping of viruses associated with diseases that produced poxs in the skin.  Modern viral classification is based on the shape and molecular features of viruses, and the smallpox virus remains as the most notable member of the family.
The only other poxvirus known to specifically infect humans is the molluscum contagiosum virus (MCV).
Poxviridae
Herpesviridae
Adenoviridae
Hantavirus
Arenavirus
Endornavirus
Benyvirus
Cheravirus