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71-577: Prior to American occupation the Spanish city of St. Augustine was predominately Catholic and the only burial ground within the city, the Tolomato cemetery, was reserved for Catholics. Recognizing a need for a formal Protestant burial ground an area just outside the city gate was chosen by the new American administration in St. Augustine. The first burials occurred in 1821 just prior to a yellow fever epidemic which claimed

142-671: A Level 2 alert (practice enhanced precautions.) A Bayesian analysis of genotypes I and II has shown that genotype I accounts for virtually all the current infections in Brazil , Colombia , Venezuela , and Trinidad and Tobago , while genotype II accounted for all cases in Peru . Genotype I originated in the northern Brazilian region around 1908 (95% highest posterior density interval [HPD]: 1870–1936). Genotype II originated in Peru in 1920 (95% HPD: 1867–1958). The estimated rate of mutation for both genotypes

213-413: A polyprotein . Host proteases cut this polyprotein into three structural (C, prM, E) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5); the enumeration corresponds to the arrangement of the protein coding genes in the genome . Minimal YFV 3 ′ UTR region is required for stalling of the host 5 ′ -3 ′ exonuclease XRN1. The UTR contains PKS3 pseudoknot structure, which serves as

284-758: A WHO-approved vaccination center is required. Although 32 of 44 countries where yellow fever occurs endemically do have vaccination programmes, in many of these countries, less than 50% of their population is vaccinated. Control of the yellow fever mosquito A. aegypti is of major importance, especially because the same mosquito can also transmit dengue fever and chikungunya disease. A. aegypti breeds preferentially in water, for example, in installations by inhabitants of areas with precarious drinking water supplies, or in domestic refuse, especially tires, cans, and plastic bottles. These conditions are common in urban areas in developing countries. Two main strategies are employed to reduce A. aegypti populations. One approach

355-570: A billion people live in an area of the world where the disease is common. It is common in tropical areas of the continents of South America and Africa, but not in Asia. Since the 1980s, the number of cases of yellow fever has been increasing. 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. The disease originated in Africa and spread to

426-464: A biopsy is only advisable post mortem to confirm the cause of death. In a differential diagnosis , infections with yellow fever must be distinguished from other feverish illnesses such as malaria . Other viral hemorrhagic fevers , such as Ebola virus , Lassa virus , Marburg virus , and Junin virus , must be excluded as the cause. Personal prevention of yellow fever includes vaccination and avoidance of mosquito bites in areas where yellow fever

497-424: A day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin . If this occurs, the risk of bleeding and kidney problems is increased. The disease is caused by the yellow fever virus and is spread by the bite of an infected mosquito . It infects humans, other primates , and several types of mosquitoes. In cities, it is spread primarily by Aedes aegypti ,

568-442: A molecular signal to stall the exonuclease and is the only viral requirement for subgenomic flavivirus RNA (sfRNA) production. The sfRNAs are a result of incomplete degradation of the viral genome by the exonuclease and are important for viral pathogenicity. Yellow fever belongs to the group of hemorrhagic fevers . The viruses infect, amongst others, monocytes , macrophages , Schwann cells , and dendritic cells . They attach to

639-422: A period of twice the incubation period of the infectious disease has elapsed without identification of any new case, however, for organisms with a short incubation period (e.g. fewer than ten days), a period of three times the incubation period is preferred. Outbreak legislation is still in its infancy and not many countries have had a direct and complete set of the provisions. However, some countries do manage

710-493: A rearrangement of the 90 homo dimers to 60 homo trimers . After entering the host cell, the viral genome is replicated in the rough endoplasmic reticulum (ER) and in the so-called vesicle packets. At first, an immature form of the virus particle is produced inside the ER, whose M-protein is not yet cleaved to its mature form, so is denoted as precursor M (prM) and forms a complex with protein E. The immature particles are processed in

781-549: A reduced volume of vaccine dose, which has been reconstituted as per manufacturer recommendations. The first practical use of fractional dose yellow fever vaccination was in response to a large yellow fever outbreak in the Democratic Republic of the Congo in mid-2016. Available evidence shows that fractional dose yellow fever vaccination induces a level of immune response similar to that of the standard full dose. In March 2017,

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852-494: A type of mosquito found throughout the tropics and subtropics . The virus is an RNA virus of the genus Flavivirus . The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood-sample testing with a polymerase chain reaction is required. A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers. Other efforts to prevent infection include reducing

923-421: Is common in tropical and subtropical areas of South America and Africa. Worldwide, about 600 million people live in endemic areas. The WHO estimates 200,000 cases of yellow fever worldwide each year. About 15% of people infected with yellow fever progress to a severe form of the illness, and up to half of those will die, as there is no cure for yellow fever. An estimated 90% of yellow fever infections occur on

994-413: Is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire continent. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics , which term

1065-431: Is caused by yellow fever virus (YFV), an enveloped RNA virus 40–50 nm in width, the type species and namesake of the family Flaviviridae . It was the first illness shown to be transmissible by filtered human serum and transmitted by mosquitoes, by American doctor Walter Reed around 1900. The positive- sense , single-stranded RNA is around 10,862 nucleotides long and has a single open reading frame encoding

1136-625: Is endemic. Institutional measures for prevention of yellow fever include vaccination programmes and measures to control mosquitoes. Programmes for distribution of mosquito nets for use in homes produce reductions in cases of both malaria and yellow fever. Use of EPA-registered insect repellent is recommended when outdoors. Exposure for even a short time is enough for a potential mosquito bite. Long-sleeved clothing, long pants, and socks are useful for prevention. The application of larvicides to water-storage containers can help eliminate potential mosquito breeding sites. EPA-registered insecticide spray decreases

1207-643: Is fatal in 60% of cases. It is probably due to the genetic morphology of the immune system. Another possible side effect is an infection of the nervous system, which occurs in one in 200,000 to 300,000 cases, causing yellow fever vaccine-associated neurotropic disease, which can lead to meningoencephalitis and is fatal in less than 5% of cases. The Yellow Fever Initiative, launched by the WHO in 2006, vaccinated more than 105 million people in 14 countries in West Africa. No outbreaks were reported during 2015. The campaign

1278-504: Is known as acquired immunity . The virus, as well as the vector A. aegypti, were probably transferred to North and South America with the trafficking of slaves from Africa, part of the Columbian exchange following European exploration and colonization. However, some researchers have argued that yellow fever might have existed in the Americas during the pre-Columbian period as mosquitoes of

1349-497: Is normally only for infectious diseases , as well as diseases with an environmental origin, such as a water or foodborne disease . They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks when multiple and various countries around the Earth are soon infected. The terms "outbreak" and "epidemic" have often been used interchangeably. Researchers Manfred S. Green and colleagues propose that

1420-470: Is not recommended by the WHO. Insecticide-treated mosquito nets are effective, just as they are against the Anopheles mosquito that carries malaria. As with other Flavivirus infections, no cure is known for yellow fever. Hospitalization is advisable and intensive care may be necessary because of rapid deterioration in some cases. Certain acute treatment methods lack efficacy: passive immunization after

1491-514: Is obtained. Waiting until the end of an investigation to implement prevention and control measures is a sure way to lose ones job. In outbreaks identified through notifiable disease surveillance, reports are often linked to laboratory results and verifying the diagnosis is straight forward. In outbreaks of unknown etiology, determining and verifying the diagnosis can be a significant part of the investigation with respect to time and resources. Several steps are usually going on at any point in time during

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1562-437: Is quite a foot longer than the other two. A low coquina curb around the three. Grave not marked during Leed's 1893 survey: Yellow fever Yellow fever is a viral disease of typically short duration . In most cases, symptoms include fever , chills , loss of appetite , nausea , muscle pains—particularly in the back—and headaches . Symptoms typically improve within five days. In about 15% of people, within

1633-410: Is recommended as a chemical larvicide, mainly because it is safe for humans and effective in small doses. The second strategy is to reduce populations of the adult yellow fever mosquito. Lethal ovitraps can reduce Aedes populations, using lesser amounts of pesticide because it targets the pest directly. Curtains and lids of water tanks can be sprayed with insecticides, but application inside houses

1704-427: Is taken up by a female mosquito when it ingests the blood of an infected human or another primate. Viruses reach the stomach of the mosquito, and if the virus concentration is high enough, the virions can infect epithelial cells and replicate there. From there, they reach the haemocoel (the blood system of mosquitoes) and from there the salivary glands . When the mosquito next sucks blood, it injects its saliva into

1775-543: Is the absence of a slave trade to Asia on the scale of that to the Americas. The trans-Atlantic slave trade probably introduced yellow fever into the Western Hemisphere from Africa. The evolutionary origins of yellow fever most likely lie in Africa, with transmission of the disease from nonhuman primates to humans. The virus is thought to have originated in East or Central Africa and spread from there to West Africa. As it

1846-507: Is to kill the developing larvae. Measures are taken to reduce the water accumulations in which the larvae develop. Larvicides are used, along with larvae-eating fish and copepods , which reduce the number of larvae. For many years, copepods of the genus Mesocyclops have been used in Vietnam for preventing dengue fever. This eradicated the mosquito vector in several areas. Similar efforts may prove effective against yellow fever. Pyriproxyfen

1917-545: The Golgi apparatus by the host protein furin , which cleaves prM to M. This releases E from the complex, which can now take its place in the mature, infectious virion . Yellow fever virus is mainly transmitted through the bite of the yellow fever mosquito Aedes aegypti , but other mostly Aedes mosquitoes such as the tiger mosquito ( Aedes albopictus ) can also serve as a vector for this virus. Like other arboviruses , which are transmitted by mosquitoes, yellow fever virus

1988-775: The Huguenots , a French Protestant sect started in the 16th century in France. INSCRIPTIONS IN THE OLD PROTESTANT GRAVEYARD AT ST. AUGUSTINE, FLORIDA. Vol. XLVII Palatka , Fla. Oct. 20, 1881. Aged 5 years 18 days. This grave is about 7 feet from the south fence of the yard. North of this line of graves and southeast of the Douglas Pacetti grave are the two following: Single grave with cement curb and head and footboard but no inscription - an evergreen anonymous with curbing. A grave with palings around in very shaky condition - no mark. Directly adjoining above north - North of and directly adjoining

2059-684: The Napoleonic Wars , the West Indies were known as a particularly dangerous posting for soldiers due to yellow fever being endemic in the area. The mortality rate in British garrisons in Jamaica was seven times that of garrisons in Canada, mostly because of yellow fever and other tropical diseases. Both English and French forces posted there were seriously affected by the "yellow jack." Wanting to regain control of

2130-437: The 22d of January, 1825, etatis 31. Vertical marble slab on raised brick foundation. A marble horizontal slab on raised marble faced foundation. Lot enclosed with iron fence. Mrs. _________, 1841. A bit of stone with this inscription. In a lot with cement (over coquina) curbing level with the ground without it. The above, each covered with horizontal marble slab on raised cement foundation, differ only in length. The middle slab

2201-653: The African continent. In 2016, a large outbreak originated in Angola and spread to neighboring countries before being contained by a massive vaccination campaign. 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. Phylogenetic analysis has identified seven genotypes of yellow fever viruses, and they are assumed to be differently adapted to humans and to

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2272-521: The Americas starting in the 17th century with the European trafficking of enslaved Africans from sub-Saharan Africa. Since the 17th century, several major outbreaks of the disease have occurred in the Americas, Africa, and Europe. In the 18th and 19th centuries, yellow fever was considered one of the most dangerous infectious diseases ; numerous epidemics swept through major cities of the US and in other parts of

2343-523: The Democratic Republic of Congo (2016), Uganda (2016), and more recently in Nigeria and Brazil in 2017 have further increased demand, while straining global vaccine supply. Therefore, to vaccinate susceptible populations in preventive mass immunization campaigns during outbreaks, fractional dosing of the vaccine is being considered as a dose-sparing strategy to maximize limited vaccine supplies. Fractional dose yellow fever vaccination refers to administration of

2414-790: The East African genotype, which had remained undetected in the previous 40 years. In South America, two genotypes have been identified (South American genotypes I and II). Based on phylogenetic analysis these two genotypes appear to have originated in West Africa and were first introduced into Brazil. The date of introduction of the predecessor African genotype which gave rise to the South American genotypes appears to be 1822 (95% confidence interval 1701 to 1911). The historical record shows an outbreak of yellow fever occurred in Recife, Brazil, between 1685 and 1690. The disease seems to have disappeared, with

2485-624: The French troops survived for withdrawal and return to France. Napoleon gave up on the island and his plans for North America, selling the Louisiana Purchase to the US in 1803. In 1804, Haiti proclaimed its independence as the second republic in the Western Hemisphere. Considerable debate exists over whether the number of deaths caused by disease in the Haitian Revolution was exaggerated. Outbreak In epidemiology , an outbreak

2556-468: The Public Health Agency of Canada. There are several outbreak patterns, which can be useful in identifying the transmission method or source, and predicting the future rate of infection. Each has a distinctive epidemic curve , or histogram of case infections and deaths. Outbreaks can also be: Patterns of occurrence are: By convention, a communicable disease outbreak is declared over when

2627-514: The WHO launched a vaccination campaign in Brazil with 3.5 million doses from an emergency stockpile. In March 2017 the WHO recommended vaccination for travellers to certain parts of Brazil. In March 2018, Brazil shifted its policy and announced it planned to vaccinate all 77.5 million currently unvaccinated citizens by April 2019. Some countries in Asia are considered to be potentially in danger of yellow fever epidemics, as both mosquitoes with

2698-409: The WHO on 17 May 2013 advised that subsequent booster vaccinations are unnecessary, an older (than 10 years) certificate may not be acceptable at all border posts in all affected countries. A list of the countries that require yellow fever vaccination is published by the WHO. If the vaccination cannot be given for some reason, dispensation may be possible. In this case, an exemption certificate issued by

2769-572: The above a mound, and adjoining this mound northwardly another and shorter - Neither marked. As the Thomas grave and these two are so close together, the interred may be related. These succeed, through some distance - 10 feet north - from the two children's graves mentioned above on this page. A vertical marble slab. This stone of same height as the above, but outline at top different. They however seem to belong together. Louisa Charlotte Izard , daut of Ralph and Elizabeth Izard , of South Carolina, who died on

2840-441: The above steps and relative amount of effort and resources used in each varies from outbreak to outbreak. For example, prevention and control measures are usually implemented very early in the investigation, often before the causative agent is known. In many situations, promoting good hygiene and hand-washing is one of the first things recommended. Other interventions may be added as the investigation moves forward and more information

2911-407: The capability to transmit yellow fever as well as susceptible monkeys are present. The disease does not yet occur in Asia. To prevent introduction of the virus, some countries demand previous vaccination of foreign visitors who have passed through yellow fever areas. Vaccination has to be proved by a vaccination certificate, which is valid 10 days after the vaccination and lasts for 10 years. Although

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2982-399: The cell surfaces via specific receptors and are taken up by an endosomal vesicle . Inside the endosome , the decreased pH induces the fusion of the endosomal membrane with the virus envelope . The capsid enters the cytosol , decays, and releases the genome. Receptor binding, as well as membrane fusion, are catalyzed by the protein E, which changes its conformation at low pH, causing

3053-472: The detection of IgM or a four-fold increase in IgG titer is considered sufficient indication for yellow fever. As these tests can cross-react with other flaviviruses, such as dengue virus , these indirect methods cannot conclusively prove yellow fever infection. Liver biopsy can verify inflammation and necrosis of hepatocytes and detect viral antigens . Because of the bleeding tendency of yellow fever patients,

3124-562: The disease by the name "yellow fever" occurred in 1744. However, Dr. Mitchell misdiagnosed the disease that he observed and treated, and the disease was probably Weil's disease or hepatitis. McNeill argues that the environmental and ecological disruption caused by the introduction of sugar plantations created the conditions for mosquito and viral reproduction, and subsequent outbreaks of yellow fever. Deforestation reduced populations of insectivorous birds and other creatures that fed on mosquitoes and their eggs. In Colonial times and during

3195-498: The disease can only be confirmed virologically. Since mild cases of yellow fever can also contribute significantly to regional outbreaks, every suspected case of yellow fever (involving symptoms of fever, pain, nausea, and vomiting 6–10 days after leaving the affected area) is treated seriously. If yellow fever is suspected, the virus cannot be confirmed until 6–10 days following the illness. A direct confirmation can be obtained by reverse transcription polymerase chain reaction , where

3266-417: The disease characterized by recurring fever, this time accompanied by jaundice due to liver damage , as well as abdominal pain . Bleeding in the mouth, nose, eyes, and the gastrointestinal tract cause vomit containing blood , hence one of the names in Spanish for yellow fever, vómito negro ("black vomit"). There may also be kidney failure, hiccups, and delirium. Among those who develop jaundice,

3337-493: The emergence of symptoms is probably without effect; ribavirin and other antiviral drugs , as well as treatment with interferons , are ineffective in yellow fever patients. Symptomatic treatment includes rehydration and pain relief with drugs such as paracetamol (acetaminophen). However, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) are often avoided because of an increased risk of gastrointestinal bleeding due to their anticoagulant effects. Yellow fever

3408-500: The fatality rate is 20 to 50%, while the overall fatality rate is about 3 to 7.5%. Severe cases may have a mortality rate greater than 50%. Surviving the infection provides lifelong immunity , and normally results in no permanent organ damage. Yellow fever can lead to death for 20% to 50% of those who develop severe disease. Jaundice, fatigue, heart rhythm problems, seizures and internal bleeding may also appear as complications of yellow fever during recovery time. Yellow fever

3479-441: The genome of the virus is amplified. Another direct approach is the isolation of the virus and its growth in cell culture using blood plasma ; this can take 1–4 weeks. Serologically, an enzyme-linked immunosorbent assay during the acute phase of the disease using specific IgM against yellow fever or an increase in specific IgG titer (compared to an earlier sample) can confirm yellow fever. Together with clinical symptoms,

3550-607: The genus Haemagogus , which is indigenous to the Americas, have been known to carry the disease. The first definitive outbreak of yellow fever in the New World was in 1647 on the island of Barbados . An outbreak was recorded by Spanish colonists in 1648 in the Yucatán Peninsula , where the indigenous Mayan people called the illness xekik ("blood vomit"). In 1685, Brazil suffered its first epidemic in Recife . The first mention of

3621-420: The investigation. Steps may be repeated. For example, initial case definitions are often established to be intentionally broad but later refined as more is learned about the outbreak. The above list has 9 steps, others have more. Implementing active surveillance to identify additional cases is often added. Outbreak debriefing and review has also been recognized as an additional final step and iterative process by

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3692-441: The jungle and urban cycles. Different mosquitoes of the genus Aedes are involved. In recent years, this has been the most common form of transmission of yellow fever in Africa. Concern exists about yellow fever spreading to southeast Asia, where its vector A. aegypti already occurs. After transmission from a mosquito, the viruses replicate in the lymph nodes and infect dendritic cells in particular. From there, they reach

3763-471: The latter term be restricted to larger events, pointing out that Chambers Concise Dictionary and Stedman's Medical Dictionary acknowledge this distinction. When investigating disease outbreaks, the epidemiology profession has developed a number of widely accepted steps. As described by the United States Centers for Disease Control and Prevention , these include the following: The order of

3834-468: The liver and infect hepatocytes (probably indirectly via Kupffer cells ), which leads to eosinophilic degradation of these cells and to the release of cytokines . Apoptotic masses known as Councilman bodies appear in the cytoplasm of hepatocytes. Fatality may occur when cytokine storm , shock , and multiple organ failure follow. Yellow fever is most frequently a clinical diagnosis , based on symptomatology and travel history. Mild cases of

3905-576: The lives of a large numbers of the city's inhabitants. The cemetery until title to the cemetery property was acquired by the Rev. Thomas Alexander, who then turned over it to the Presbyterian Church in 1832, burials continued until 1884 when both Huguenot and Tolomato cemeteries were closed. The cemetery is believed to hold at least 436 burials according to city records. The cemetery although named " Huguenot Cemetery " isn't believed to contain any members of

3976-475: The lucrative sugar trade in Saint-Domingue (Hispaniola), and with an eye on regaining France's New World empire, Napoleon sent an army under the command of his brother-in-law General Charles Leclerc to Saint-Domingue to seize control after a slave revolt. The historian J. R. McNeill asserts that yellow fever accounted for about 35,000 to 45,000 casualties of these forces during the fighting. Only one-third of

4047-469: The next outbreak occurring in 1849. It was likely introduced with the trafficking of slaves through the slave trade from Africa. Genotype I has been divided into five subclades, A through E. In late 2016, a large outbreak began in Minas Gerais state of Brazil that was characterized as a sylvatic or jungle epizootic . Real-time phylogenetic investigations at the epicentre of the outbreak revealed that

4118-481: The only way unvaccinated humans can become infected, which explains the low incidence of yellow fever cases on the continent. People who become infected in the jungle can carry the virus to urban areas, where A. aegypti acts as a vector. Because of this sylvatic cycle, yellow fever cannot be eradicated except by completely eradicating the mosquitoes that serve as vectors. In Africa, a third infectious cycle known as "savannah cycle" or intermediate cycle, occurs between

4189-478: The outbreak was caused by the introduction of a virus lineage from the Amazon region into the southeast region around July 2016, spreading rapidly across several neotropical monkey species, including brown howler monkeys, which serve as a sentinel species for yellow fever. No cases had been transmitted between humans by the A. aegypti mosquito, which can sustain urban outbreaks that can spread rapidly. In April 2017,

4260-588: The population of the transmitting mosquitoes. In areas where yellow fever is common, early diagnosis of cases and immunization of large parts of the population are important to prevent outbreaks . Once a person is infected, management is symptomatic; no specific measures are effective against the virus. Death occurs in up to half of those who get severe disease. In 2013, yellow fever was estimated to have caused 130,000 severe infections and 78,000 deaths in Africa. Approximately 90 percent of an estimated 200,000 cases of yellow fever per year occur in Africa. Nearly

4331-562: The sylvatic outbreak continued moving toward the Brazilian coast, where most people were unvaccinated. By the end of May the outbreak appeared to be declining after more than 3,000 suspected cases, 758 confirmed and 264 deaths confirmed to be yellow fever. The Health Ministry launched a vaccination campaign and was concerned about spread during the Carnival season in February and March. The CDC issued

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4402-505: The transmission of yellow fever. Vaccination is recommended for those traveling to affected areas, because non-native people tend to develop more severe illness when infected. Protection begins by the 10th day after vaccine administration in 95% of people, and had been reported to last for at least 10 years. The World Health Organization (WHO) now states that a single dose of vaccine is sufficient to confer lifelong immunity against yellow fever disease. The attenuated live vaccine stem 17D

4473-516: The urban cycle, both in Africa and South America, a sylvatic cycle (forest or jungle cycle) is present, where Aedes africanus (in Africa) or mosquitoes of the genus Haemagogus and Sabethes (in South America) serve as vectors. In the jungle, the mosquitoes infect mainly nonhuman primates; the disease is mostly asymptomatic in African primates. In South America, the sylvatic cycle is currently

4544-587: 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. 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

4615-587: The virus is transmitted from mosquitoes to humans or other primates. In the "urban cycle", only the yellow fever mosquito A. aegypti is involved. It is well adapted to urban areas, and can also transmit other diseases, including Zika fever , dengue fever , and chikungunya . The urban cycle is responsible for the major outbreaks of yellow fever that occur in Africa. Except for an outbreak in Bolivia in 1999, this urban cycle no longer exists in South America. Besides

4686-423: The world. In 1927, yellow fever virus became the first human virus to be isolated. Yellow fever begins after an incubation period of three to six days. Most cases cause only mild infection with fever, headache, chills, back pain, fatigue, loss of appetite, muscle pain, nausea, and vomiting. In these cases, the infection lasts only three to six days. But in 15% of cases, people enter a second, toxic phase of

4757-461: The wound, and the virus reaches the bloodstream of the bitten person. Transovarial transmissionial and transstadial transmission of yellow fever virus within A. aegypti , that is, the transmission from a female mosquito to its eggs and then larvae, are indicated. This infection of vectors without a previous blood meal seems to play a role in single, sudden breakouts of the disease. Three epidemiologically different infectious cycles occur in which

4828-487: Was about 5 × 10  substitutions/site/year, similar to that of other RNA viruses. The main vector ( A. aegypti ) also occurs in tropical and subtropical regions of Asia, the Pacific, and Australia, but yellow fever had never occurred there until jet travel introduced 11 cases from the 2016 Angola and DR Congo yellow fever outbreak in Africa. Proposed explanations include: But none is considered satisfactory. Another proposal

4899-411: Was developed in 1937 by Max Theiler . The WHO recommends routine vaccination for people living in affected areas between the 9th and 12th month after birth. Up to one in four people experience fever, aches, and local soreness and redness at the site of injection. In rare cases (less than one in 200,000 to 300,000), the vaccination can cause yellow fever vaccine-associated viscerotropic disease, which

4970-407: Was endemic in Africa, local populations had developed some immunity to it. When an outbreak of yellow fever would occur in an African community where colonists resided, most Europeans died, while the indigenous Africans usually developed nonlethal symptoms resembling influenza . This phenomenon, in which certain populations develop immunity to yellow fever due to prolonged exposure in their childhood,

5041-657: Was supported by the GAVI alliance and governmental organizations in Europe and Africa. According to the WHO, mass vaccination cannot eliminate yellow fever because of the vast number of infected mosquitoes in urban areas of the target countries, but it will significantly reduce the number of people infected. Demand for yellow fever vaccine has continued to increase due to the growing number of countries implementing yellow fever vaccination as part of their routine immunization programmes. Recent upsurges in yellow fever outbreaks in Angola (2015),

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