Slow virus

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]

Characteristics

Every infectious agent is different, but in general, slow viruses:[4]

• 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,[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]

Scope

Slow viruses cause a variety of diseases, including cancer.

Examples of viral agents

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]

^§JC virus & BK virus only cause disease in immunocompromised patients

See also

• Clinical latency
• Virus latency

References

1. "About HIV/AIDS | HIV Basics | HIV/AIDS". U.S. Centers for Disease Control and Prevention. 2019-02-28. Retrieved 2019-03-05.
2. "Subacute Sclerosing Panencephalitis". PubMed Health. National Center for Biotechnology Information, U.S. National Library of Medicine. Archived from the original on 25 February 2014. Retrieved 10 February 2012.
3. Roodman GD, Windle JJ (February 2005). "Paget disease of bone". The Journal of Clinical Investigation. 115 (2): 200–208. doi:10.1172/JCI24281. PMC 546434. PMID 15690073.
4. Levinson W, Chin-Hong P, Joyce EA, Nussbaum J, Schwartz B, eds. (2020). "Slow Viruses & Prions.". Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases (16th ed.). McGraw Hill.
5. Bocharov G, Ludewig B, Bertoletti A, Klenerman P, Junt T, Krebs P, et al. (March 2004). "Underwhelming the immune response: effect of slow virus growth on CD8+-T-lymphocyte responses". Journal of Virology. 78 (5): 2247–2254. doi:10.1128/jvi.78.5.2247-2254.2004. PMC 369240. PMID 14963121.
6. Pinto M, Dobson S (January 2014). "BK and JC virus: a review". The Journal of Infection. 68 (Suppl 1): S2 – S8. doi:10.1016/j.jinf.2013.09.009. PMID 24119828.
7. Bradford BM, Mabbott NA (December 2012). "Prion disease and the innate immune system". Viruses. 4 (12): 3389–3419. doi:10.3390/v4123389. PMC 3528271. PMID 23342365.
8. Haridy R (2022-02-25). "The new science linking cancer, schizophrenia and MS to viral infections". New Atlas. Retrieved 2022-02-28.
9. Garg RK (February 2002). "Subacute sclerosing panencephalitis". Postgraduate Medical Journal. 78 (916): 63–70. doi:10.1136/pmj.78.916.63. PMC 1742261. PMID 11807185.
10. Kuroda Y, Matsui M (April 1997). "[Progressive rubella panencephalitis]". Nihon Rinsho. Japanese Journal of Clinical Medicine (in Japanese). 55 (4): 922–925. PMID 9103895.
11. Hemachudha T, Ugolini G, Wacharapluesadee S, Sungkarat W, Shuangshoti S, Laothamatas J (May 2013). "Human rabies: neuropathogenesis, diagnosis, and management". The Lancet. Neurology. 12 (5): 498–513. doi:10.1016/S1474-4422(13)70038-3. PMID 23602163. S2CID 1798889.
12. Soong TR, Milner Jr DA (2015). "Human Papillomavirus Infection". In Milner Jr DA, Pecora N, Solomon I, Soong TR (eds.). Diagnostic Pathology: Infectious Diseases. Elsevier Health Sciences. p. 40. ISBN 978-0-323-40037-4. Archived from the original on 11 September 2017.