Yellow fever

Yellow fever
Other namesYellow jack, yellow plague,[1] bronze john[2]
A TEM micrograph of yellow fever virus (234,000× magnification)
SpecialtyInfectious disease
SymptomsFever, chills, muscle pain, yellow skin[3]
ComplicationsLiver failure, bleeding[3]
Usual onset3–6 days post exposure[3]
Duration3–4 days[3]
CausesYellow fever virus spread by mosquitoes[3]
Diagnostic methodBlood test[4]
PreventionYellow fever vaccine[3]
TreatmentSupportive care[3]
Frequency~127,000 severe cases (2013)[3]
Deaths5,100 (2015)[5]

Yellow fever is a viral disease of typically short duration.[3] In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains particularly in the back, and headaches.[3] Symptoms typically improve within five days.[3] In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin.[3][6] If this occurs, the risk of bleeding and kidney problems is also increased.[3]

The disease is caused by yellow fever virus and is spread by the bite of an infected female mosquito.[3] It infects only humans, other primates, and several species of mosquitoes.[3] In cities, it is spread primarily by Aedes aegypti, a type of mosquito found throughout the tropics and subtropics.[3] The virus is an RNA virus of the genus Flavivirus.[7] The disease may be difficult to tell apart from other illnesses, especially in the early stages.[3] To confirm a suspected case, blood sample testing with polymerase chain reaction is required.[4]

A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers.[3] Other efforts to prevent infection include reducing the population of the transmitting mosquito.[3] In areas where yellow fever is common and vaccination is uncommon, early diagnosis of cases and immunization of large parts of the population are important to prevent outbreaks.[3] Once infected, management is symptomatic with no specific measures effective against the virus.[3] Death occurs in up to half of those who get severe disease.[3][8]

In 2013, yellow fever resulted in about 127,000 severe infections and 45,000 deaths,[3] with nearly 90% of these occurring in African nations.[4] Nearly a billion people live in an area of the world where the disease is common.[3] It is common in tropical areas of the continents of South America and Africa, but not in Asia.[3][9] Since the 1980s, the number of cases of yellow fever has been increasing.[3][10] This is believed to be due to fewer people being immune, more people living in cities, people moving frequently, and changing climate increasing the habitat for mosquitoes.[3] The disease originated in Africa, from where it spread to South America through the slave trade in the 17th century.[1] Since the 17th century, several major outbreaks of the disease have occurred in the Americas, Africa, and Europe.[1] In the 18th and 19th centuries, yellow fever was seen as one of the most dangerous infectious diseases.[1] In 1927 yellow fever virus became the first human virus to be isolated.[7][11]

Signs and symptoms

Yellow fever begins after an incubation period of three to six days.[12] Most cases only cause a mild infection with fever, headache, chills, back pain, fatigue, loss of appetite, muscle pain, nausea, and vomiting.[13] In these cases, the infection lasts only three to four days.

In 15% of cases, however, people enter a second, toxic phase of the disease with recurring fever, this time accompanied by jaundice due to liver damage, as well as abdominal pain.[14] Bleeding in the mouth, the eyes, and the gastrointestinal tract cause vomit containing blood, hence the Spanish name for yellow fever, vómito negro ("black vomit").[15] There may also be kidney failure, hiccups, and delirium.[16][17]

Among those who develop jaundice the fatality rate is 20% to 50%, while the overall fatality rate is about 5%.[18] Severe cases may have a mortality greater than 50%.[19]

Surviving the infection provides lifelong immunity,[20] and normally no permanent organ damage results.[21]

Other Languages
Afrikaans: Geelkoors
العربية: حمى صفراء
asturianu: Fiebre mariello
azərbaycanca: Sarı qızdırma
বাংলা: পীতজ্বর
беларуская: Жоўтая ліхаманка
български: Жълта треска
bosanski: Žuta groznica
català: Febre groga
čeština: Žlutá zimnice
dansk: Gul feber
Deutsch: Gelbfieber
ދިވެހިބަސް: ރީނދޫ ހުން
español: Fiebre amarilla
Esperanto: Flava febro
euskara: Sukar hori
فارسی: تب زرد
français: Fièvre jaune
Gaeilge: Fiabhras buí
한국어: 황열
հայերեն: Դեղին տենդ
हिन्दी: पीतज्वर
hrvatski: Žuta groznica
Bahasa Indonesia: Demam kuning
italiano: Febbre gialla
Kiswahili: Homa ya manjano
Kreyòl ayisyen: Lafyèv jòn
lingála: Fièvre jaune
Luganda: Enkaka
magyar: Sárgaláz
македонски: Жолта треска
മലയാളം: മഞ്ഞപ്പനി
Bahasa Melayu: Demam kuning dewasa
Nederlands: Gele koorts
日本語: 黄熱
norsk: Gulfeber
ଓଡ଼ିଆ: ପୀତ ଜ୍ୱର
português: Febre amarela
română: Febră galbenă
Runa Simi: Fiebre amarilla
Simple English: Yellow fever
slovenščina: Rumena mrzlica
српски / srpski: Žuta groznica
srpskohrvatski / српскохрватски: Žuta groznica
suomi: Keltakuume
svenska: Gula febern
ትግርኛ: ብጫ ረስኒ
Türkçe: Sarıhumma
Thuɔŋjäŋ: Juanmaketh
українська: Жовта гарячка
اردو: زرد بخار
Tiếng Việt: Sốt vàng
粵語: 黃熱病
中文: 黄热病