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,<ref>{{Cite web|url=https://www.cdc.gov/hiv/basics/whatishiv.html|title=About HIV/AIDS {{!}} HIV Basics {{!}} HIV/AIDS |date=2019-02-28| publisher = U.S. Centers for Disease Control and Prevention |language=en-us|access-date=2019-03-05}}</ref> subacute sclerosing panencephalitis, the rare result of a measles virus infection,<ref>{{cite web | work = PubMed Health | publisher = National Center for Biotechnology Information, U.S. National Library of Medicine | url = https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002392 | archive-url = https://web.archive.org/web/20140225233200/http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002392/ | archive-date = 25 February 2014 | title = Subacute Sclerosing Panencephalitis | access-date = 10 February 2012 }}</ref> and Paget's disease of bone (osteitis deformans), which may be associated with paramyxoviruses, especially the measles virus and the human respiratory syncytial virus.<ref name="pmid15690073">{{cite journal | vauthors = Roodman GD, Windle JJ | title = Paget disease of bone | journal = The Journal of Clinical Investigation | volume = 115 | issue = 2 | pages = 200–208 | date = February 2005 | pmid = 15690073 | pmc = 546434 | doi = 10.1172/JCI24281 }}</ref>

==Characteristics==

Every infectious agent is different, but in general, slow viruses:<ref>{{cite book | chapter = Slow Viruses & Prions. | veditors = Levinson W, Chin-Hong P, Joyce EA, Nussbaum J, Schwartz B | title = Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases | edition = 16th | publisher = McGraw Hill | date = 2020 | chapter-url = https://accessmedicine.mhmedical.com/content.aspx?bookid=2867&sectionid=242761049 }}</ref> :* Cause an asymptomatic primary infection :* Have a long incubation period ranging from months to years :* Follow a slow but relentless progressive course leading to death :* Tend to have a genetic predisposition :* Often re-emerge from latency if the host becomes immuno-compromised

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,<ref name="pmid14963121">{{cite journal | vauthors = Bocharov G, Ludewig B, Bertoletti A, Klenerman P, Junt T, Krebs P, Luzyanina T, Fraser C, Anderson RM | display-authors = 6 | title = Underwhelming the immune response: effect of slow virus growth on CD8+-T-lymphocyte responses | journal = Journal of Virology | volume = 78 | issue = 5 | pages = 2247–2254 | date = March 2004 | pmid = 14963121 | pmc = 369240 | doi = 10.1128/jvi.78.5.2247-2254.2004 }}</ref> preexisting immunosuppression (as in the cases of JC virus and BK virus),<ref name=JCBKReview>{{cite journal | vauthors = Pinto M, Dobson S | title = BK and JC virus: a review | journal = The Journal of Infection | volume = 68 | issue = Suppl 1 | pages = S2–S8 | date = January 2014 | pmid = 24119828 | doi = 10.1016/j.jinf.2013.09.009 }}</ref> or, in the case of prions, the identity of the agent involved.<ref name="pmid23342365">{{cite journal | vauthors = Bradford BM, Mabbott NA | title = Prion disease and the innate immune system | journal = Viruses | volume = 4 | issue = 12 | pages = 3389–3419 | date = December 2012 | pmid = 23342365 | pmc = 3528271 | doi = 10.3390/v4123389 | doi-access = free }}</ref>

== Scope == Slow viruses cause a variety of diseases, including cancer. {| class="wikitable" |+Examples of viral agents |- ! Virus !! Virus family !! Disease !! Typical latency !! Transmitted by |- | JC virus (Human polyomavirus 2) || Polyomavirus || Progressive multifocal leukoencephalopathy || Years to Life<sup>§</sup> || Unknown; possibly contaminated water<ref name="JCBKReview" /> |- | BK virus || Polyomavirus || BK nephropathy, bladder cancer<ref>{{Cite web | vauthors = Haridy R |date=2022-02-25 |title=The new science linking cancer, schizophrenia and MS to viral infections |url=https://newatlas.com/science/bladder-cancer-schizophrenia-ms-dementia-viral-infections/ |access-date=2022-02-28 |website=New Atlas |language=en-US}}</ref> || Years to life<sup>§</sup> || Unknown; possibly respiratory spread/urine; possibly contaminated water<ref name="JCBKReview" /> |- | Measles virus || Paramyxovirus || Subacute sclerosing panencephalitis || 1–10 years|| Respiratory droplets<ref name="pmid11807185">{{cite journal | vauthors = Garg RK | title = Subacute sclerosing panencephalitis | journal = Postgraduate Medical Journal | volume = 78 | issue = 916 | pages = 63–70 | date = February 2002 | pmid = 11807185 | pmc = 1742261 | doi = 10.1136/pmj.78.916.63 }}</ref> |- | Rubella virus || Togaviridae || Progressive rubella panencephalitis || 10–20 years|| Respiratory droplets<ref name="pmid9103895">{{cite journal | vauthors = Kuroda Y, Matsui M | title = [Progressive rubella panencephalitis] | language = Japanese | journal = Nihon Rinsho. Japanese Journal of Clinical Medicine | volume = 55 | issue = 4 | pages = 922–925 | date = April 1997 | pmid = 9103895 | doi = }}</ref> |- | Rabies virus || Rhabdoviridae || Rabies || 3–12 weeks || Bite of an infected animal<ref name="pmid23602163">{{cite journal | vauthors = Hemachudha T, Ugolini G, Wacharapluesadee S, Sungkarat W, Shuangshoti S, Laothamatas J | title = Human rabies: neuropathogenesis, diagnosis, and management | journal = The Lancet. Neurology | volume = 12 | issue = 5 | pages = 498–513 | date = May 2013 | pmid = 23602163 | doi = 10.1016/S1474-4422(13)70038-3 | s2cid = 1798889 }}</ref> |- |Human papillomavirus infection |''Papillomaviridae'' |Cancers of the cervix, oropharynx, vulva, anal, penis, vagina and rectum. |Years |Sexual activity<ref name="Mil2015">{{cite book | vauthors = Soong TR, Milner Jr DA | chapter = Human Papillomavirus Infection | chapter-url=https://books.google.com/books?id=YJ_uCQAAQBAJ&pg=PA40 | veditors = Milner Jr DA, Pecora N, Solomon I, Soong TR |title=Diagnostic Pathology: Infectious Diseases |date=2015 |publisher=Elsevier Health Sciences |isbn=978-0-323-40037-4 |page=40 |archive-url=https://web.archive.org/web/20170911003204/https://books.google.com/books?id=YJ_uCQAAQBAJ&pg=PA40 |archive-date=11 September 2017 |url-status=live |name-list-style=vanc |df=dmy-all}}</ref> |}

:<sup>§</sup>JC virus & BK virus only cause disease in immunocompromised patients

== See also == * Clinical latency * Virus latency

== References == {{Reflist}}

{{DEFAULTSORT:Slow Virus}} Category:Virology Category:Slow virus diseases