When not inside a cell or in the process of infecting a cell, viruses exist in the form of independent particles called virions. (wikipedia.org)
Most of these viruses are bacteriophages which infect and destroy marine bacteria and control the growth of phytoplankton at the base of the marine food web. (wikipedia.org)
Bacteriophages, often contracted to phages, are viruses that parasitize bacteria for replication. (wikipedia.org)
Such a feature is unique among bacterial viruses (i.e., bacteriophages) and the mechanisms of virion envelopment within a bacterial host are largely unknown. (biomedcentral.com)