Editing Measles (section)

==Cause==
[[File:Measles virus.JPG|thumb|upright=1.3|An electron micrograph of the measles virus]]
Measles is caused by the [[measles virus]], a single-stranded, non-segmented, [[Sense (molecular biology)#RNA sense in viruses|negative-sense]], [[Viral envelope|enveloped]] [[RNA virus]] of the genus ''[[Morbillivirus]]'' within the family ''[[Paramyxoviridae]]''.<ref name=":16" /><ref name="Bester2016" /> It is related most closely to [[rinderpest]], a cattle virus eradicated in 2001, and [[canine distemper]], a mammalian disease that causes neurologic deterioration.<ref name="Pink Book" /> There are 24 [[Strain (biology)|strains]] of measles virus divided into eight [[clade]]s designated A-H.<ref name=":16" />

The virus is one of the most contagious human pathogens and is spread by coughing and sneezing via close personal contact or direct contact with secretions.<ref name="cdc.gov" /><ref name="Bester2016" /><ref name=":16">{{Cite journal |last1=Hübschen |first1=Judith M. |last2=Gouandjika-Vasilache |first2=Ionela |last3=Dina |first3=Julia |date=12 February 2022 |title=Measles |url=https://pubmed.ncbi.nlm.nih.gov/35093206 |journal=Lancet |volume=399 |issue=10325 |pages=678–690 |doi=10.1016/S0140-6736(21)02004-3 |issn=1474-547X |pmid=35093206}}</ref> It remains infectious for up to two hours via suspended respiratory droplets.<ref name="Pink Book" /> It is not easily spread by [[fomite]]s, because the virus is inactivated within a few hours by [[Ultraviolet|ultraviolet light]] and heat.<ref name="Rot2016" /> It is also inactivated by [[trypsin]], acidic environments, and [[ether]].<ref name="Pink Book" /> Measles is so contagious that if one person has it, 90% of non-immune people who have close contact with them (e.g., household members) will also become infected.<ref name="Pink Book" /><ref name="pmid31480896">{{cite journal | vauthors=Banerjee E, Griffith J, Kenyon C, Christianson B, Strain A, Martin K | display-authors=etal | title=Containing a measles outbreak in Minnesota, 2017: methods and challenges. | journal=Perspect Public Health | year=2020 | volume=140 | issue=3 | pages=162–171 | pmid=31480896 | doi=10.1177/1757913919871072 | pmc= | s2cid=201829328 | url=https://pubmed.ncbi.nlm.nih.gov/31480896 | archive-date=2 May 2023 | archive-url=https://web.archive.org/web/20230502182530/https://journals.sagepub.com/doi/10.1177/1757913919871072?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed | url-status=live }}</ref> Humans are the only natural hosts of the virus, and no other animal [[Natural reservoir|reservoirs]] are known to exist, although mountain gorillas are believed to be susceptible to the disease.<ref name="Pink Book" /><ref name="pmid24450064">{{cite journal |vauthors=Spelman LH, Gilardi KV, Lukasik-Braum M, Kinani JF, Nyirakaragire E, Lowenstine LJ | display-authors=etal | title=Respiratory disease in mountain gorillas (Gorilla beringei beringei) in Rwanda, 1990-2010: outbreaks, clinical course, and medical management. | journal=J Zoo Wildl Med | year=2013 | volume=44 | issue=4 | pages=1027–35 | pmid=24450064 | doi=10.1638/2013-0014R.1 | pmc= | url=https://pubmed.ncbi.nlm.nih.gov/24450064| archive-date=2 May 2023 | archive-url=https://web.archive.org/web/20230502182527/https://bioone.org/journals/journal-of-zoo-and-wildlife-medicine/volume-44/issue-4/2013-0014R.1/RESPIRATORY-DISEASE-IN-MOUNTAIN-GORILLAS-GORILLA-BERINGEI-BERINGEI-IN-RWANDA/10.1638/2013-0014R.1.short | url-status=live }}</ref>
Risk factors for measles virus infection include [[immunodeficiency]] caused by [[HIV/AIDS]],<ref>{{cite journal | vauthors = Gowda VK, Sukanya V | title = Acquired immunodeficiency syndrome with subacute sclerosing panencephalitis | journal = Pediatric Neurology | volume = 47 | issue = 5 | pages = 379–81 | date = November 2012 | pmid = 23044024 | doi = 10.1016/j.pediatrneurol.2012.06.020 }}</ref> [[immunosuppression]] following receipt of an [[Organ transplantation|organ]] or a [[hematopoietic stem cell transplantation|stem cell transplant]],<ref>{{cite journal | vauthors = Waggoner JJ, Soda EA, Deresinski S | title = Rare and emerging viral infections in transplant recipients | journal = Clinical Infectious Diseases | volume = 57 | issue = 8 | pages = 1182–8 | date = October 2013 | pmid = 23839998 | doi = 10.1093/cid/cit456 | pmc = 7107977 | doi-access = free | title-link = doi }}</ref> [[Alkylation|alkylating agents]], or [[Corticosteroid#Medical uses|corticosteroid therapy]], regardless of immunization status;<ref name=Medscape2018/> travel to areas where measles commonly occurs or contact with travelers from such an area;<ref name=Medscape2018/> and the loss of passive, inherited antibodies before the age of routine immunization.<ref name=Leuridan2012/>