 Even if a virus is able to bind to a host cell and transfer its genetic material through the cell membrane, the cell may not contain the necessary polymerases and enzymes necessary for viral replication to occur and for pathogenesis to continue.Many pathogens also contain important virulence factors within their genomes.In particular, pathogenic bacteria are capable of translating virulence genes located within their plasmids into different virulence factors in order to aid the bacterium in pathogenesis.