Editing Yellow fever (section)

===Africa===
[[File:Yellow fever Africa 2009.jpeg|thumb|upright=1.2|Areas with risk of yellow fever in Africa (2017)]]

An estimated 90% of yellow fever infections occur on the African continent.<ref name=Toll2009/> In 2016, [[2016 Angola and DR Congo yellow fever outbreak|a large outbreak originated in Angola]] and spread to neighboring countries before being contained by a massive vaccination campaign.<ref>{{Cite web |title=Mass vaccination campaign to protect millions against yellow fever in Angola and the Democratic Republic of the Congo |url=https://www.who.int/news-room/feature-stories/detail/mass-vaccination-campaign-to-protect-millions-against-yellow-fever-in-angola-and-democratic-republic-of-the-congo |access-date=2022-04-25 |website=World Health Organization |language=en}}</ref> In March and April 2016, 11 imported cases of the Angola genotype in unvaccinated Chinese nationals were reported in China, the first appearance of the disease in Asia in recorded history.<ref>{{cite web |title=Yellow Fever – China |url=https://www.who.int/csr/don/22-april-2016-yellow-fever-china/en/ |website=World Health Organization |access-date=9 February 2017 |archive-url=https://web.archive.org/web/20170319162041/http://who.int/csr/don/22-april-2016-yellow-fever-china/en/ |archive-date=19 March 2017}}</ref><ref>{{cite journal | vauthors = Woodall JP, Yuill TM | title = Why is the yellow fever outbreak in Angola a 'threat to the entire world'? | journal = International Journal of Infectious Diseases | volume = 48 | pages = 96–97 | date = July 2016 | pmid = 27163382 | doi = 10.1016/j.ijid.2016.05.001 | doi-access = free }}</ref>

[[Phylogenetic]] analysis has identified seven [[genotype]]s of yellow fever viruses, and they are assumed to be differently adapted to humans and to the vector ''A. aegypti''. Five genotypes (Angola, Central/East Africa, East Africa, West Africa I, and West Africa II) occur only in Africa. West Africa genotype I is found in [[Nigeria]] and the surrounding region.<ref name=Mutebi2002>{{cite journal | vauthors = Mutebi JP, Barrett AD | title = The epidemiology of yellow fever in Africa | journal = Microbes and Infection | volume = 4 | issue = 14 | pages = 1459–1468 | date = November 2002 | pmid = 12475636 | doi = 10.1016/S1286-4579(02)00028-X }}</ref> West Africa genotype I appears to be especially infectious, as it is often associated with major outbreaks. The three genotypes found outside of Nigeria and Angola occur in areas where outbreaks are rare. Two outbreaks, in Kenya (1992–1993) and Sudan (2003 and 2005), involved the East African genotype, which had remained undetected in the previous 40 years.<ref name=Ellis2008>{{cite journal | vauthors = Ellis BR, Barrett AD | title = The enigma of yellow fever in East Africa | journal = Reviews in Medical Virology | volume = 18 | issue = 5 | pages = 331–346 | year = 2008 | pmid = 18615782 | doi = 10.1002/rmv.584 }}</ref>