Measles pathophysiology: Difference between revisions
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==Overview== | ==Overview== | ||
Measles is a [[ | Measles is caused by a nonsegmented negative-stranded [[RNA virus]] of the [[Paramyxoviridae]] family, genus [[Morbillivirus]]. The primary site of infection is the [[respiratory epithelium]] of the [[nasopharynx]] and it is transmitted in respiratory secretions, via aerosol droplets containing virus particles. | ||
==Pathogenesis== | ==Pathogenesis== | ||
* Measles is a systemic infection.<ref name=CDC1>{{cite web | title = Measles: Epidemiology and Prevention of Vaccine-Preventable Diseases | url = http://www.cdc.gov/vaccines/pubs/pinkbook/meas.html#pathogenesis }}</ref> | * Measles is a systemic infection.<ref name=CDC1>{{cite web | title = Measles: Epidemiology and Prevention of Vaccine-Preventable Diseases | url = http://www.cdc.gov/vaccines/pubs/pinkbook/meas.html#pathogenesis }}</ref> | ||
* The primary site of infection is the [[respiratory epithelium] of the [[nasopharynx]]. | * The primary site of infection is the [[respiratory epithelium]] of the [[nasopharynx]]. | ||
* Cellular receptors: CD46 ( | * Cellular receptors: CD46 (ubiquitous) and CD150 ([[antigen-presenting cells]] and [[lymphocytes]]).<ref name="pmid16963735">{{cite journal| author=Yanagi Y, Takeda M, Ohno S| title=Measles virus: cellular receptors, tropism and pathogenesis. | journal=J Gen Virol | year= 2006 | volume= 87 | issue= Pt 10 | pages= 2767-79 | pmid=16963735 | doi=10.1099/vir.0.82221-0 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16963735 }} </ref> | ||
* Two to three days after invasion and replication in the [[respiratory epithelium]] and regional [[lymph nodes]], a primary viremia occurs with subsequent infection of the [[reticuloendothelial system | * Two to three days after invasion and replication in the [[respiratory epithelium]] and regional [[lymph nodes]], a primary viremia occurs with subsequent infection of the [[reticuloendothelial system]]. | ||
* Following further viral replication in regional and distal reticuloendothelial sites, a second viremia occurs 5–7 days after initial infection. | * Following further viral replication in regional and distal reticuloendothelial sites, a second viremia occurs 5–7 days after initial infection. | ||
* During this viremia, there may be [[infection]] of the [[respiratory]] tract and other organs. | * During this viremia, there may be [[infection]] of the [[respiratory]] tract and other organs. | ||
* Measles virus is shed from the [[nasopharynx]] beginning with the prodrome until 3–4 days after rash onset. | * Measles virus is shed from the [[nasopharynx]] beginning with the prodrome until 3–4 days after rash onset. | ||
* The symptoms are caused by the immune response. | |||
* At the acute phase of the infection, the [[IL-2]] drives the immune response to a stronger [[Th1 response]] and cellular T-cell [[CD8]] response, which is vital for viral elimination. <ref name="pmid19203109">{{cite journal| author=Naniche D| title=Human immunology of measles virus infection. | journal=Curr Top Microbiol Immunol | year= 2009 | volume= 330 | issue= | pages= 151-71 | pmid=19203109 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19203109 }} </ref><ref name="pmid20636817">{{cite journal| author=Griffin DE| title=Measles virus-induced suppression of immune responses. | journal=Immunol Rev | year= 2010 | volume= 236 | issue= | pages= 176-89 | pmid=20636817 | doi=10.1111/j.1600-065X.2010.00925.x | pmc=PMC2908915 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20636817 }} </ref> | |||
* Later on, the secretion of IL-4 and IL-10 rises, driving the immune response to a stronger [[Th2 response]] and inhibiting the [[Th2 response]] respectively, which allows the development of measles virus-specific [[antibodies]] and establishment of long-term immunity.<ref name="pmid19203109">{{cite journal| author=Naniche D| title=Human immunology of measles virus infection. | journal=Curr Top Microbiol Immunol | year= 2009 | volume= 330 | issue= | pages= 151-71 | pmid=19203109 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19203109 }} </ref> | |||
* The measles infection induces [[immunosuppression]] in the host even months after the resoluton of the [[infection]], predisposing the host to other [[infections]].<ref name="pmid20376484">{{cite journal| author=Avota E, Gassert E, Schneider-Schaulies S| title=Measles virus-induced immunosuppression: from effectors to mechanisms. | journal=Med Microbiol Immunol | year= 2010 | volume= 199 | issue= 3 | pages= 227-37 | pmid=20376484 | doi=10.1007/s00430-010-0152-3 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20376484 }} </ref> | |||
* Alterations on the immune response include<ref name="pmid20376484">{{cite journal| author=Avota E, Gassert E, Schneider-Schaulies S| title=Measles virus-induced immunosuppression: from effectors to mechanisms. | journal=Med Microbiol Immunol | year= 2010 | volume= 199 | issue= 3 | pages= 227-37 | pmid=20376484 | doi=10.1007/s00430-010-0152-3 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20376484 }} </ref>: | |||
** [[Lymphopenia]] | |||
** Suppression of [[cellular immunity]] | |||
** Inhibition of multiplication of periphereal blood [[lymphocytes]] | |||
==Transmission== | ==Transmission== | ||
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* German measles is an unrelated condition caused by the [[rubella]] virus. | * German measles is an unrelated condition caused by the [[rubella]] virus. | ||
* Humans are the only known natural hosts of measles, although the virus can infect some non-human primate species. | * Humans are the only known natural hosts of measles, although the virus can infect some non-human primate species. | ||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
{{WH}} | |||
{{WS}} | |||
[[Category:Pediatrics]] | [[Category:Pediatrics]] | ||
[[Category:Dermatology]] | [[Category:Dermatology]] | ||
[[Category:Viral diseases]] | [[Category:Viral diseases]] | ||
[[Category:Mononegavirales]] | [[Category:Mononegavirales]] | ||
[[Category:Ophthalmology]] | [[Category:Ophthalmology]] | ||
[[Category:Otolaryngology]] | [[Category:Otolaryngology]] | ||
[[Category:Pulmonology]] | [[Category:Pulmonology]] | ||
[[Category:Disease]] | [[Category:Disease]] | ||
Latest revision as of 22:40, 29 July 2020
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Guillermo Rodriguez Nava, M.D. [2]
Overview
Measles is caused by a nonsegmented negative-stranded RNA virus of the Paramyxoviridae family, genus Morbillivirus. The primary site of infection is the respiratory epithelium of the nasopharynx and it is transmitted in respiratory secretions, via aerosol droplets containing virus particles.
Pathogenesis
- Measles is a systemic infection.[1]
- The primary site of infection is the respiratory epithelium of the nasopharynx.
- Cellular receptors: CD46 (ubiquitous) and CD150 (antigen-presenting cells and lymphocytes).[2]
- Two to three days after invasion and replication in the respiratory epithelium and regional lymph nodes, a primary viremia occurs with subsequent infection of the reticuloendothelial system.
- Following further viral replication in regional and distal reticuloendothelial sites, a second viremia occurs 5–7 days after initial infection.
- During this viremia, there may be infection of the respiratory tract and other organs.
- Measles virus is shed from the nasopharynx beginning with the prodrome until 3–4 days after rash onset.
- The symptoms are caused by the immune response.
- At the acute phase of the infection, the IL-2 drives the immune response to a stronger Th1 response and cellular T-cell CD8 response, which is vital for viral elimination. [3][4]
- Later on, the secretion of IL-4 and IL-10 rises, driving the immune response to a stronger Th2 response and inhibiting the Th2 response respectively, which allows the development of measles virus-specific antibodies and establishment of long-term immunity.[3]
- The measles infection induces immunosuppression in the host even months after the resoluton of the infection, predisposing the host to other infections.[5]
- Alterations on the immune response include[5]:
- Lymphopenia
- Suppression of cellular immunity
- Inhibition of multiplication of periphereal blood lymphocytes
Transmission
- The measles is a highly contagious airborne pathogen which spreads primarily via the respiratory system.
- The virus is transmitted in respiratory secretions, and can be passed from person to person via aerosol droplets containing virus particles, such as those produced by a coughing patient.
- The virus resides in the mucus in the nose and throat of the infected person. When that person sneezes or coughs, droplets spray into the air. The infected mucus can land in other people’s noses or throats when they breathe or put their fingers in their mouth or nose after handling an infected surface.
- The virus remains active and contagious on infected surfaces for up to 2 hours. Measles spreads so easily that anyone who is not immunized will probably get it, eventually.
- Once transmission occurs, the virus infects the epithelial cells of its new host, and may also replicate in the urinary tract, lymphatic system, conjunctivae, blood vessels, and central nervous system.[6]
- It spreads through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious— 90% of people without immunity sharing a house with an infected person will catch it.
- Airborne precautions should be taken for all suspected cases of measles.
- The incubation period usually lasts for 4–12 days (during which there are no symptoms).
- Infected people remain contagious from the appearance of the first symptoms until 3–5 days after the rash appears.
- German measles is an unrelated condition caused by the rubella virus.
- Humans are the only known natural hosts of measles, although the virus can infect some non-human primate species.
References
- ↑ "Measles: Epidemiology and Prevention of Vaccine-Preventable Diseases".
- ↑ Yanagi Y, Takeda M, Ohno S (2006). "Measles virus: cellular receptors, tropism and pathogenesis". J Gen Virol. 87 (Pt 10): 2767–79. doi:10.1099/vir.0.82221-0. PMID 16963735.
- ↑ 3.0 3.1 Naniche D (2009). "Human immunology of measles virus infection". Curr Top Microbiol Immunol. 330: 151–71. PMID 19203109.
- ↑ Griffin DE (2010). "Measles virus-induced suppression of immune responses". Immunol Rev. 236: 176–89. doi:10.1111/j.1600-065X.2010.00925.x. PMC 2908915. PMID 20636817.
- ↑ 5.0 5.1 Avota E, Gassert E, Schneider-Schaulies S (2010). "Measles virus-induced immunosuppression: from effectors to mechanisms". Med Microbiol Immunol. 199 (3): 227–37. doi:10.1007/s00430-010-0152-3. PMID 20376484.
- ↑ Flint SJ, Enquist LW, Racaniello VR, and AM Skalka. Principles of Virology, 2nd edition: Molecular Biology, Pathogenesis, and Control of Animal Viruses. Text " 2004" ignored (help)