Not just those but there are various other lesser known latent viruses such as JC virus and BK virus. Most of us are infected with these viruses latently. For most of us, they do nothing (that we know of!) for life. For the immunosuppressed (eg AIDS, organ transplants), because there is no immune system to keep these viruses "latent", they do actually reactivate and cause problems. For viruses which operate by embedding themselves in the DNA itself, such that for some time the virus may only exist as information encoded in some nucleotides and not a physical virus, to cure that would be a powerful achievement