Vaccinia virus (VACV) is the prototypic member of the Poxviridae a group of large DNA
viruses that replicate in the cell cytoplasm. The entry and exit of VACV are complicated by
the existence of two distinct forms of virus, intracellular mature virus (IMV) and extracellular
enveloped virus (EEV), that are surrounded by different numbers of lipid membranes and
have different surface proteins. Here the mechanisms used by these different forms of VACV
to leave the infected cell are reviewed. Whereas some enveloped viruses complete virus …