Editing Infection (section)

===Transmission<!--linked from 'Transmission (medicine)'-->===
{{Main|Transmission (medicine)}}
[[File:CulexNil.jpg|thumb|220px|A southern house mosquito (''[[Culex quinquefasciatus]]'') is a [[disease vector|vector]] that transmits the pathogens that cause [[West Nile fever]] and [[avian malaria]] among others.]]For infecting organisms to survive and repeat the infection cycle in other hosts, they (or their progeny) must leave an existing reservoir and cause infection elsewhere. Infection transmission can take place via many potential routes:<ref>{{cite web | title = How Infections Spread | url = https://www.cdc.gov/infectioncontrol/spread/index.html | website = Centers for Disease Control and Prevention | date = 1 January 2016 | access-date = 17 October 2021 | archive-date = 2 June 2023 | archive-url = https://web.archive.org/web/20230602112416/https://www.cdc.gov/infectioncontrol/spread/index.html | url-status = live }}</ref>
* '''Droplet contact''', also known as the ''respiratory route'', and the resultant infection can be termed [[airborne disease]]. If an infected person coughs or sneezes on another person the microorganisms, suspended in warm, moist droplets, may enter the body through the nose, mouth or eye surfaces.
* '''Fecal-oral transmission''', wherein foodstuffs or water become contaminated (by people not washing their hands before preparing food, or untreated sewage being released into a drinking water supply) and the people who eat and drink them become infected. Common [[Fecal–oral route|fecal-oral]] transmitted pathogens include ''[[Vibrio cholerae]]'', ''[[Giardia]]'' species, [[rotavirus]]es, ''[[Entamoeba histolytica]]'', ''[[Escherichia coli]]'', and [[tape worm]]s.<ref>[http://www.fungusfocus.com/html/flukes.htm Intestinal Parasites and Infection] {{Webarchive|url=https://web.archive.org/web/20101028013944/http://fungusfocus.com/html/flukes.htm |date=2010-10-28 }} fungusfocus.com – Retrieved on 2010-01-21</ref> Most of these pathogens cause [[gastroenteritis]].
* '''Sexual transmission''', with the result being called [[sexually transmitted infection]].
* '''Oral transmission''', diseases that are transmitted primarily by oral means may be caught through direct oral contact such as [[kiss]]ing, or by indirect contact such as by sharing a drinking glass or a cigarette.
* '''Transmission by direct contact''', Some diseases that are transmissible by direct contact include [[athlete's foot]], [[impetigo]] and [[wart]]s.
* '''Vehicle transmission''', transmission by an inanimate reservoir (food, water, soil).<ref>{{Cite web|url=http://www.microbiologybook.org/Infectious%20Disease/Infectious%20Disease%20Introduction.htm|title=Clinical Infectious Disease – Introduction|website=microbiologybook.org|access-date=2017-04-19|archive-date=2017-04-20|archive-url=https://web.archive.org/web/20170420143405/http://www.microbiologybook.org/Infectious%20Disease/Infectious%20Disease%20Introduction.htm|url-status=live}}</ref>
* '''[[Vertically transmitted infection|Vertical transmission]]''', directly from the mother to an [[embryo]], [[fetus]] or baby during [[pregnancy]] or [[childbirth]]. It can occur as a result of a [[pre-existing disease in pregnancy|pre-existing infection]] or one acquired during pregnancy.
* '''[[Iatrogenic]] transmission''', due to medical procedures such as [[Injection (medicine)|injection]] or [[organ transplant|transplantation]] of infected material.
* '''Vector-borne transmission''', transmitted by a [[Vector (epidemiology)|vector]], which is an [[organism]] that does not cause [[disease]] itself but that transmits infection by conveying [[pathogen]]s from one [[Host (biology)|host]] to another.<ref>[http://www.metapathogen.com/ Pathogens and vectors] {{Webarchive|url=https://web.archive.org/web/20171005150918/http://www.metapathogen.com/ |date=2017-10-05 }}. ''MetaPathogen.com''.</ref>

The relationship between ''[[optimal virulence|virulence versus transmissibility]]'' is complex; with studies have shown that there were no clear relationship between the two.<ref>{{cite journal |last1=Hector |first1=Tobias E. |last2=Booksmythe |first2=Isobel |title=Digest: Little evidence exists for a virulence-transmission trade-off* |journal=Evolution |date=April 2019 |volume=73 |issue=4 |pages=858–859 |doi=10.1111/evo.13724 |pmid=30900249 |s2cid=85448255 |doi-access=free }}</ref><ref>{{cite journal |last1=Acevedo |first1=Miguel A. |last2=Dillemuth |first2=Forrest P. |last3=Flick |first3=Andrew J. |last4=Faldyn |first4=Matthew J. |last5=Elderd |first5=Bret D. |title=Virulence-driven trade-offs in disease transmission: A meta-analysis* |journal=Evolution |date=April 2019 |volume=73 |issue=4 |pages=636–647 |doi=10.1111/evo.13692 |pmid=30734920 |s2cid=73418339 |url=https://digitalcommons.lsu.edu/biosci_pubs/1193 |access-date=2022-06-28 |archive-date=2022-12-04 |archive-url=https://web.archive.org/web/20221204210544/https://digitalcommons.lsu.edu/biosci_pubs/1193/ |url-status=live }}</ref> There is still a small number of evidence that partially suggests a link between virulence and transmissibility.<ref>{{cite journal |last1=Ericson |first1=L. |last2=Burdon |first2=J. J. |last3=Müller |first3=W. J. |title=Spatial and temporal dynamics of epidemics of the rust fungus Uromyces valerianae on populations of its host Valeriana salina |journal=Journal of Ecology |date=August 1999 |volume=87 |issue=4 |pages=649–658 |doi=10.1046/j.1365-2745.1999.00384.x |s2cid=86478171 |doi-access=free |bibcode=1999JEcol..87..649E }}</ref><ref>{{cite journal |last1=Mideo |first1=N |last2=Alizon |first2=S |last3=Day |first3=T |title=Linking within- and between-host dynamics in the evolutionary epidemiology of infectious diseases |journal=Trends in Ecology & Evolution |date=September 2008 |volume=23 |issue=9 |pages=511–517 |doi=10.1016/j.tree.2008.05.009|pmid=18657880 |bibcode=2008TEcoE..23..511M }}</ref><ref>{{cite journal |last1=Mordecai |first1=Erin A. |last2=Cohen |first2=Jeremy M. |last3=Evans |first3=Michelle V. |last4=Gudapati |first4=Prithvi |last5=Johnson |first5=Leah R. |last6=Lippi |first6=Catherine A. |last7=Miazgowicz |first7=Kerri |last8=Murdock |first8=Courtney C. |last9=Rohr |first9=Jason R. |last10=Ryan |first10=Sadie J. |last11=Savage |first11=Van |last12=Shocket |first12=Marta S. |last13=Stewart Ibarra |first13=Anna |last14=Thomas |first14=Matthew B. |last15=Weikel |first15=Daniel P. |title=Detecting the impact of temperature on transmission of Zika, dengue, and chikungunya using mechanistic models |journal=PLOS Neglected Tropical Diseases |date=27 April 2017 |volume=11 |issue=4 |pages=e0005568 |doi=10.1371/journal.pntd.0005568|pmid=28448507 |pmc=5423694 |doi-access=free }}</ref>