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{{Molluscum contagiosum}}
{{Molluscum contagiosum}}


{{CMG}}
{{CMG}};{{AE}}{{MIR}}
 
==Overview==
==Overview==
This is a common infection in children and occurs when a child comes into direct contact with a lesion. The virus can spread through contact with contaminated objects, such as towels, clothing, or toys. The virus also spreads by sexual contact. Persons with a weakened immune system (due to conditions such as AIDS) may have a rapidly worse case of molluscum contagiosum.
Molluscum contagiosum is usually transmitted via direct contact with a skin lesion. Following transmission, molluscum contagiosum uses the human cell machinery to replicate. On gross [[pathology]], a central umbilication and punctiform [[vessels]] are characteristic findings of molluscum contagiosum. On [[Electron microscope|electron microscopic]] analysis, typical brick-shaped [[poxvirus]] particles inside the infected tissue are characteristic findings of molluscum contagiosum.


==Pathophysiology==
==Pathogenesis==
The time from infection to the appearance of lesions ranges from 1 week to 6 months, with an average incubation period of 6 weeks. Diagnosis is made on the clinical appearance.
*The human molluscum contagiosum virus (MCV) is a DNA [[Poxviridae|poxvirus]]. 
===Transmission===
*MCV has no animal reservoir, infecting only [[human]]s.
In adults, molluscum infections are often [[sexually transmitted]] and usually affect the [[genitals]], lower [[abdomen]], [[buttocks]], and inner thighs. In rare cases, molluscum infections are also found on the [[lips]], [[mouth]], and eyelids. It is spread through direct contact or shared articles of clothing (including towels).  
*MCV replicates in cells [[cytoplasm]]. This may be related to genetic similarity in [[variola]] and [[vaccinia]] viruses more than one-half.
*In adults, molluscum infections are often [[sexually transmitted]] and usually affect the [[genitals]], lower [[abdomen]], [[buttocks]], and inner thighs. In rare cases, molluscum contagiosum infections are also found on the [[lips]], [[mouth]], and eyelids. It spread through direct contact or shared articles of clothing (including towels).
*MCV can commonly cause asymptomatic cutaneous [[Neoplasm|neoplasms]]. Children and sexually active adults as well as persistent opportunistic [[acquired immunodeficiency syndrome]] (AIDS)-associated disease are more sensitive to the virus and more in danger for cutaneous [[neoplasm]]. <ref name="pmid8941326">{{cite journal |vauthors=Fife KH, Whitfeld M, Faust H, Goheen MP, Bryan J, Brown DR |title=Growth of molluscum contagiosum virus in a human foreskin xenograft model |journal=Virology |volume=226 |issue=1 |pages=95–101 |year=1996 |pmid=8941326 |doi=10.1006/viro.1996.0631 |url=}}</ref>
==Genetics==
*In 1997, Senkevich et al were the first who described [[molluscum contagiosum virus]] (MCV) genome.<ref name="pmid92012142">{{cite journal |vauthors=Senkevich TG, Koonin EV, Bugert JJ, Darai G, Moss B |title=The genome of molluscum contagiosum virus: analysis and comparison with other poxviruses |journal=Virology |volume=233 |issue=1 |pages=19–42 |year=1997 |pmid=9201214 |doi=10.1006/viro.1997.8607 |url=}}</ref>
*MCV possesses 59 genes predicted to code for novel proteins including [[MHC class I|MHC-class I]], [[chemokine]], and [[glutathione peroxidase]] homologs not found in other [[Poxvirus|poxviruses]]. The MCV genomic data is near complete which can allow the investigation of host defense mechanisms. These information also can provide new possibilities for the development of therapeutics for treatment and prevention of the MCV infection.<ref name="pmid9413524">{{cite journal |vauthors=Bugert JJ, Darai G |title=Recent advances in molluscum contagiosum virus research |journal=Arch. Virol. Suppl. |volume=13 |issue= |pages=35–47 |year=1997 |pmid=9413524 |doi= |url=}}</ref><ref name="pmid9201214">{{cite journal |vauthors=Senkevich TG, Koonin EV, Bugert JJ, Darai G, Moss B |title=The genome of molluscum contagiosum virus: analysis and comparison with other poxviruses |journal=Virology |volume=233 |issue=1 |pages=19–42 |year=1997 |pmid=9201214 |doi=10.1006/viro.1997.8607 |url=}}</ref>
*Molluscum contagiosum inhibits the host [[inflammatory]] response. This unique feature seems to be related to some of the specific genes that are present in its genome.
*Scientists have sequenced more than 190-kilobase pair genome of MCV. These genome findings have revealed that the virus potentially encodes approximately 182 proteins, 105 of which have direct counterparts in orthopoxviruses (OPV).<ref name="pmid8941326" /> Another study suggests that MCV lacks counterparts to 83 genes of the [[smallpox virus]], including those important in suppression of host responses to [[infection]], [[nucleotide]] [[biosynthesis]], and [[cell proliferation]].<ref name="pmid9413524" />


===Virology===
==Gross Pathology==
MC has no animal reservoir, infecting only [[human]]s, as did [[smallpox]]. However, there are different pox viruses that infect  many other mammals. The infecting human MC virus is a DNA [[Poxviridae|poxvirus]] called the ''[[molluscum contagiosum virus]]'' (MCV).  There are 4 types of MCV, MCV-1 to -4, with MCV-1 being the most prevalent and MCV-2 seen usually in adults and often sexually transmitted.
In a dermoscopic exam of infected tissue the important parts include:
*A central umbilication with polylobular, white to yellow amorphous structures
*A peripheral crown of radiating or punctiform vessels<ref name="pmid9201214" />
==Microscopic Pathology==
[[Electron microscope|Electron microscopic]] evaluation of tissue is not a part of routine diagnosis procedure, but if done it may show:<ref name="pmid9201214" />
* Typical brick-shaped [[poxvirus]] particles inside the infected tissue which is highly specific for diagnosis
* [[Electron microscopy]] can also identify infected cells that appear normal on [[light microscopy]]


==References==
==References==
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{{Reflist|2}}
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Latest revision as of 22:45, 29 July 2020

Molluscum contagiosum Microchapters

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Overview

Historical Perspective

Classification

Pathophysiology

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Differentiating Molluscum contagiosum from other Diseases

Epidemiology and Demographics

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Natural History, Complications and Prognosis

Diagnosis

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History and Symptoms

Physical Examination

Laboratory Findings

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Mahshid Mir, M.D. [2]

Overview

Molluscum contagiosum is usually transmitted via direct contact with a skin lesion. Following transmission, molluscum contagiosum uses the human cell machinery to replicate. On gross pathology, a central umbilication and punctiform vessels are characteristic findings of molluscum contagiosum. On electron microscopic analysis, typical brick-shaped poxvirus particles inside the infected tissue are characteristic findings of molluscum contagiosum.

Pathogenesis

  • The human molluscum contagiosum virus (MCV) is a DNA poxvirus.
  • MCV has no animal reservoir, infecting only humans.
  • MCV replicates in cells cytoplasm. This may be related to genetic similarity in variola and vaccinia viruses more than one-half.
  • In adults, molluscum infections are often sexually transmitted and usually affect the genitals, lower abdomen, buttocks, and inner thighs. In rare cases, molluscum contagiosum infections are also found on the lips, mouth, and eyelids. It spread through direct contact or shared articles of clothing (including towels).
  • MCV can commonly cause asymptomatic cutaneous neoplasms. Children and sexually active adults as well as persistent opportunistic acquired immunodeficiency syndrome (AIDS)-associated disease are more sensitive to the virus and more in danger for cutaneous neoplasm. [1]

Genetics

  • In 1997, Senkevich et al were the first who described molluscum contagiosum virus (MCV) genome.[2]
  • MCV possesses 59 genes predicted to code for novel proteins including MHC-class I, chemokine, and glutathione peroxidase homologs not found in other poxviruses. The MCV genomic data is near complete which can allow the investigation of host defense mechanisms. These information also can provide new possibilities for the development of therapeutics for treatment and prevention of the MCV infection.[3][4]
  • Molluscum contagiosum inhibits the host inflammatory response. This unique feature seems to be related to some of the specific genes that are present in its genome.
  • Scientists have sequenced more than 190-kilobase pair genome of MCV. These genome findings have revealed that the virus potentially encodes approximately 182 proteins, 105 of which have direct counterparts in orthopoxviruses (OPV).[1] Another study suggests that MCV lacks counterparts to 83 genes of the smallpox virus, including those important in suppression of host responses to infection, nucleotide biosynthesis, and cell proliferation.[3]

Gross Pathology

In a dermoscopic exam of infected tissue the important parts include:

  • A central umbilication with polylobular, white to yellow amorphous structures
  • A peripheral crown of radiating or punctiform vessels[4]

Microscopic Pathology

Electron microscopic evaluation of tissue is not a part of routine diagnosis procedure, but if done it may show:[4]

References

  1. 1.0 1.1 Fife KH, Whitfeld M, Faust H, Goheen MP, Bryan J, Brown DR (1996). "Growth of molluscum contagiosum virus in a human foreskin xenograft model". Virology. 226 (1): 95–101. doi:10.1006/viro.1996.0631. PMID 8941326.
  2. Senkevich TG, Koonin EV, Bugert JJ, Darai G, Moss B (1997). "The genome of molluscum contagiosum virus: analysis and comparison with other poxviruses". Virology. 233 (1): 19–42. doi:10.1006/viro.1997.8607. PMID 9201214.
  3. 3.0 3.1 Bugert JJ, Darai G (1997). "Recent advances in molluscum contagiosum virus research". Arch. Virol. Suppl. 13: 35–47. PMID 9413524.
  4. 4.0 4.1 4.2 Senkevich TG, Koonin EV, Bugert JJ, Darai G, Moss B (1997). "The genome of molluscum contagiosum virus: analysis and comparison with other poxviruses". Virology. 233 (1): 19–42. doi:10.1006/viro.1997.8607. PMID 9201214.

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