In some cases, the prophage DNA becomes inserted into the chromosome of its host. When these virions infect new hosts, they insert these bacterial genes into them. This process of genetic transfer, a virus-mediated transformation , is called transduction . It can express certain of its genes. For example, the gene that encodes diphtheria toxin is the property of a prophage in the diphtheria bacillus , not of the bacillus itself.
Some animal viruses can also establish latent infections.
Latent infections may also cause the cell to become cancerous. The cell has become transformed . Link to a discussion of the properties of transformed cells. Link for more details.