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relating to or caused by a virus; "viral infection"
the process whereby something is shed (同)sloughing

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ウィルスの;ウィルスが原因の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/12 01:13:19」(JST)

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Viral shedding refers to the expulsion and release of virus progeny following successful reproduction during a host-cell infection. Once replication has been completed and the host cell is exhausted of all resources in making viral progeny, the viruses may begin to leave the cell by several methods.^[1]

The term is used to refer to shedding from a single cell, shedding from one part of the body into another part of the body,^[2] and shedding from bodies into the environment where the viruses may infect other bodies.^[3]

Via budding

Generic viral budding.

"Budding" through the cell envelope—in effect, borrowing from the cell membrane to create the virus's own viral envelope—is most effective for viruses that need an envelope in the first place. These include enveloped viruses such as HIV, HSV, SARS or smallpox. Prior to budding, the virus may put its own receptor onto the surface of the cell in preparation for the virus to bud through, forming an envelope with the viral receptors already on it. Though budding does not immediately destroy the host cell, this process will slowly use up the cell membrane and eventually lead to the cell's demise. This is also how antiviral responses are able to detect virus-infected cells.^[4]

Via apoptosis

Virus forcing cell to undergo apoptosis to infect macrophages.

Animal cells are programmed to self-destruct when they are under viral attack or damaged in some other way. By forcing the cell to undergo apoptosis or cell suicide, release of progeny into the extracellular space is possible. However, apoptosis does not necessarily result in the cell simply popping open and spilling its contents into the extracellular space. Rather, apoptosis is usually controlled and results in the cell's genome being chopped up, before apoptotic bodies of dead cell material clump off the cell to be absorbed by macrophages. This is a good way for a virus to get into macrophages either to infect them or simply travel to other tissues in the body.

Although this process is primarily used by non-enveloped viruses, enveloped viruses may also use this. HIV is an example of an enveloped virus that exploits this process for the infection of macrophages.^[5]

Via exocytosis

Virus leaving via exocytosis.

Viruses also leave cells through exocytosis, in which the host cell is not destroyed. Viral progeny are synthesized within the cell and the host cell's transport system is used to enclose them in vesicles; the vesicles of virus progeny are carried to the cell membrane and then released into the extracellular space. This is used primarily by non-enveloped viruses, although enveloped viruses display this too. An example is the use of recycling viral particle receptors in the enveloped varicella-zoster virus.^[6]

References

^ N.J. Dimmock et al. "Introduction to Modern Virology, 6th edition." Blackwell Publishing, 2007.
^ [1] Massachusetts Department of Public Health - Rabies Control Plan - CHAPTER 1: GENERAL INFORMATION - "Definitions as Used in this Document [...] Shedding - The release of rabies virus from the salivary glands into the saliva."
^ J Infect Dis. 1979 Oct;140(4):610-3 article Viral shedding patterns of children with influenza B infection
^ Owen Pornillos, Jennifer E. Garrus and Wesley I. Sundquist. "Mechanisms of enveloped RNA virus budding." Trends in Cell Biology, Volume 12, Issue 12, 1 December 2002, Pages 569-579
^ Sheila A. Stewart, Betty Poon, Joo Y. Song, and Irvin S. Y. Chen. "Human Immunodeficiency Virus Type 1 Vpr Induces Apoptosis through Caspase Activation." Journal of Virology, April 2000, p. 3105-3111, Vol. 74, No. 7
^ J K Olson and C Grose. "Endocytosis and recycling of varicella-zoster virus Fc receptor glycoprotein gE: internalization mediated by a YXXL motif in the cytoplasmic tail." J Virol. 1997 May; 71(5): 4042–4054.

UpToDate Contents

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1. 性器単純ヘルペスウイルス感染の疫学、臨床症状、および診断 epidemiology clinical manifestations and diagnosis of genital herpes simplex virus infection
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4. 性器単純ヘルペスウイルス感染と妊娠 genital herpes simplex virus infection and pregnancy
5. 免疫正常患者における単純ヘルペスウイルス1型感染の治療 treatment of herpes simplex virus type 1 infection in immunocompetent patients

English Journal

ABC transporters in adaptive immunity.

Seyffer F1, Tampé R2.
Biochimica et biophysica acta.Biochim Biophys Acta.2015 Mar;1850(3):449-460. doi: 10.1016/j.bbagen.2014.05.022. Epub 2014 Jun 9.
BACKGROUND: ABC transporters ubiquitously found in all kingdoms of life move a broad range of solutes across membranes. Crystal structures of four distinct types of ABC transport systems have been solved, shedding light on different conformational states within the transport process. Briefly, ATP-de
PMID 24923865

Characterisation of a wild-type influenza (A/H1N1) virus strain as an experimental challenge agent in humans.

Watson JM, Francis JN, Mesens S, Faiman GA, Makin J, Patriarca P, Treanor JJ, Georges B, Bunce CJ.
Virology journal.Virol J.2015 Feb 3;12(1):13. [Epub ahead of print]
PMID 25645025

Association of oseltamivir treatment with virus shedding, illness, and household transmission of influenza viruses.

Cheung DH1, Tsang TK2, Fang VJ2, Xu J2, Chan KH3, Ip DK2, Peiris JS4, Leung GM2, Cowling BJ2.
The Journal of infectious diseases.J Infect Dis.2015 Feb 2. pii: jiv058. [Epub ahead of print]
In an observational study of 582 patients with laboratory-confirmed influenza virus infections, and their household contacts, we found that the initiation of oseltamivir within 24h was associated with shorter duration of self-reported illness symptoms (56% reduction in duration; 95% CI: 41%-67%). Ho
PMID 25646354

Japanese Journal

Use of quantitative real-time RT-PCR to investigate the correlation between viremia and viral shedding of canine distemper virus, and infection outcomes in experimentally infected dogs

SEHATA Go,SATO Hiroaki,ITO Toshihiro [他]
The journal of veterinary medical science 77(7), 851-855, 2015-07
NAID 40020548170

Use of quantitative real-time RT-PCR to investigate the correlation between viremia and viral shedding of canine distemper virus, and infection outcomes in experimentally infected dogs

SEHATA Go,SATO Hiroaki,ITO Toshihiro,IMAIZUMI Yoshitaka,NORO Taichi,OISHI Eiji
Journal of Veterinary Medical Science 77(7), 851-855, 2015
… Real-time RT-PCR proved extremely sensitive, and the correlation between the two methods for rectal and nasal (r=0.78, 0.80) samples on the peak day of viral RNA was good. … Although the dogs showed diverse symptoms, viral RNA kinetics were similar; … the peak of viral RNA in the symptomatic dogs was consistent with the onset of symptoms. …
NAID 130005089966

Prevalence of porcine reproductive and respiratory syndrome virus detection in aborted fetuses, mummified fetuses and stillborn piglets using quantitative polymerase chain reaction

OLANRATMANEE Em-on,WONGYANIN Piya,THANAWONGNUWECH Roongroje,TUMMARUK Padet
Journal of Veterinary Medical Science advpub(0), 2015
… The qPCR was carried out on the ORF7 of the PRRS viral genome using fluorogenic probes for amplified product detection. … These findings indicated that these specimens are important sources of the PRRS viral load and the viral shedding within the herd. …
NAID 130005061027