A slow virus is a virus, or a viruslike agent, etiologically associated with a slow virus disease. A slow virus disease is a disease that, after an extended period of latency, follows a slow, progressive course spanning months to years, frequently involves the central nervous system, and in most cases progresses to death. Examples of slow virus diseases include HIV/AIDS, caused by the HIV virus, [1] subacute sclerosing panencephalitis, the rare result of a measles virus infection, [2] and Paget's disease of bone (osteitis deformans), which may be associated with paramyxoviruses, especially the measles virus and the human respiratory syncytial virus. [3]
Every infectious agent is different, but in general, slow viruses: [4]
Additionally, the immune system seems to plays a limited role, or no role, in protection from many of these slow viruses. This may be due to the slow replication rates some of these agents exhibit, [5] preexisting immunosuppression (as in the cases of JC virus and BK virus), [6] or, in the case of prions, the identity of the agent involved. [7]
Slow viruses cause a variety of diseases, including cancer.
Virus | Virus family | Disease | Typical latency | Transmitted by |
---|---|---|---|---|
JC virus ( Human polyomavirus 2) | Polyomavirus | Progressive multifocal leukoencephalopathy | Years to Life§ | Unknown; possibly contaminated water [6] |
BK virus | Polyomavirus | BK nephropathy, bladder cancer [8] | Years to life§ | Unknown; possibly respiratory spread/urine; possibly contaminated water [6] |
Measles virus | Paramyxovirus | Subacute sclerosing panencephalitis | 1–10 years | Respiratory droplets [9] |
Rubella virus | Togaviridae | Progressive rubella panencephalitis | 10–20 years | Respiratory droplets [10] |
Rabies virus | Rhabdoviridae | Rabies | 3–12 weeks | Bite of an infected animal [11] |
Human papillomavirus infection | Papillomaviridae | Cancers of the cervix, oropharynx, vulva, anal, penis, vagina and rectum. | Years | Sexual activity [12] |