Early history can be found in New Orleans' cemeteries. The evolutionary origins of yellow fever most likely lie in Africa, with transmission of the disease from nonhuman primates to humans. 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 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.
Dr. John Mitchell of Virginia made the first recorded mention of a disease by the name "yellow fever" in 1744. However, Mitchell misdiagnosed the disease that he observed and treated, which 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 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 the highly profitable sugar trade on Hispaniola, and rejuvenate 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 inflicted between 35,000 and 45,000 casualties on French army, which was forced to withdraw, with only one-third surviving to return to France. Consequently, Napoleon abandoned his plans for North America and sold
Louisiana 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. Although yellow fever is most prevalent in tropical-like climates, the northern United States was not exempt from the fever. The first outbreak in English-speaking North America occurred in
New York City in 1668. English colonists in
Philadelphia and the French in the
Mississippi River Valley recorded major outbreaks in 1669, as well as additional yellow fever epidemics in Philadelphia,
Baltimore, and New York City in the 18th and 19th centuries. The disease traveled along
steamboat routes from New Orleans, causing some 100,000–150,000 deaths in total. The
Yellow Fever Epidemic of 1793 in Philadelphia, which was then the capital of the United States, caused thousands of deaths totaling over 9% of the city's population, including
James Hutchinson, a physician helping to treat the population of the city. As the outbreak escalated organs of the federal government fled piecemeal to the city to Trenton, New Jersey, eventually being joined by President
George Washington. This was done with little coordination or formal sanction and at times was carried out in great haste. All entities of the federal government including Congress and President soon returned to resume operations in Philadelphia as the epidemic subsided. However, another severe outbreak in 1799 culminated in an official decision to
relocate the national government to the city of Trenton, where it remained for the next six months. The southern city of
New Orleans was plagued with major epidemics during the 19th century, most notably in 1833 and 1853. A major epidemic occurred in both New Orleans and
Shreveport, Louisiana, in 1873. Its residents called the disease "yellow jack". Urban epidemics continued in the United States until 1905, with the last outbreak affecting New Orleans. At least 25 major outbreaks took place in the Americas during the 18th and 19th centuries, including particularly serious ones in
Cartagena, Chile, in 1741; Cuba in 1762 and 1900;
Santo Domingo in 1803; and
Memphis, Tennessee, in 1878. In the early 19th century, the prevalence of yellow fever in the Caribbean "led to serious health problems" and alarmed the
United States Navy as numerous deaths and sickness curtailed naval operations and destroyed morale. One episode began in April 1822 when the frigate
USS Macedonian left
Boston and became part of Commodore James Biddle's West India Squadron. Unbeknownst to all, they were about to embark on an assignment that "would prove a cruise through hell". Secretary of the Navy
Smith Thompson had assigned the squadron to guard American merchant shipping and suppress piracy. From 26 May to 3 August 1822, 76 of the
Macedonians officers and men died, including John Cadle, surgeon USN. 74 of these deaths were attributed to yellow fever. Biddle reported that another 52 of his crew were on the sick list. In their report to the secretary of the Navy, Biddle and Surgeon's Mate Charles Chase stated the cause as "fever". As a consequence of this loss, Biddle noted that his squadron was forced to return to Norfolk Navy Yard early. Upon arrival, the
Macedonians crew were provided medical care and quarantined at
Craney Island, Virginia. In 1854, 650 residents of
Savannah, Georgia, died from yellow fever. In 1858,
St. Matthew's German Evangelical Lutheran Church in
Charleston, South Carolina, had 308 yellow fever deaths, reducing the congregation by half. A ship carrying persons infected with the virus arrived in
Hampton Roads in southeastern
Virginia in June 1855. The disease spread quickly through the community, eventually killing over 3,000 people, mostly residents of Norfolk and
Portsmouth. In 1873, Shreveport lost 759 citizens in an 80-day period to a yellow fever epidemic that began in August, by November over 400 additional victims succumbed for a total death toll of approximately 1,200. The widespread
Lower Mississippi Valley yellow fever epidemic of 1878 caused an estimated 20,000 fatalities. That year, Memphis had an unusually large amount of rain, which led to an increase in the mosquito population. The result was a huge epidemic of yellow fever. The steamship John D. Porter took people fleeing Memphis northward in hopes of escaping the disease, but passengers were not allowed to disembark due to concerns of spreading yellow fever. The ship roamed the Mississippi River for the next two months before unloading her passengers. Major outbreaks have also occurred in southern Europe.
Gibraltar lost many lives to outbreaks in 1804, 1814, and 1828.
Barcelona suffered the loss of several thousand citizens during an outbreak in 1821. The
Duke de Richelieu deployed 30,000 French troops to the border between
France and
Spain in the
Pyrenees Mountains, to establish a
cordon sanitaire to prevent the epidemic from spreading from Spain into France.
Causes and transmission Ezekiel Stone Wiggins, known as the Ottawa Prophet, proposed that the cause of a yellow fever epidemic in
Jacksonville, Florida, in 1888, was astrological. In 1848,
Josiah C. Nott suggested that yellow fever was spread by insects such as moths or mosquitoes, basing his ideas on the pattern of transmission of the disease.
Carlos Finlay, a Cuban-Spanish doctor and scientist, proposed in 1881 that yellow fever might be transmitted by previously infected
mosquitoes rather than by direct contact from person to person, as had long been believed. Since the losses from yellow fever in the
Spanish–American War in the 1890s were extremely high, U.S. Army doctors began research experiments with a team led by
Walter Reed, and composed of doctors
James Carroll,
Aristides Agramonte, and
Jesse William Lazear. They successfully proved Finlay's "mosquito hypothesis". Yellow fever was the first virus shown to be transmitted by mosquitoes. The physician
William Gorgas applied these insights and eradicated yellow fever from
Havana. He also campaigned against yellow fever during the construction of the
Panama Canal. A previous effort of canal building by the French had failed in part due to mortality from the high incidence of yellow fever and malaria, which killed many workers. The acceptance of Finlay's work was one of the most important and far-reaching effects of the U.S. Army Yellow Fever Commission of 1900. Applying methods first suggested by Finlay, the United States government and Army eradicated yellow fever in Cuba and later in Panama, allowing completion of the Panama Canal. While Reed built on the research of Finlay, historian François Delaporte notes that yellow fever research was a contentious issue. Scientists, including Finlay and Reed, became successful by building on the work of less prominent scientists, without always giving them the credit they were due. Reed's research was essential in the fight against yellow fever. He is also credited for using the first type of
medical consent form during his experiments in Cuba, an attempt to ensure that participants knew they were taking a risk by being part of testing. Like Cuba and Panama, Brazil also led a highly successful sanitation campaign against mosquitoes and yellow fever. Beginning in 1903, the campaign led by
Oswaldo Cruz, then director general of public health, resulted not only in eradicating the disease but also in reshaping the physical landscape of Brazilian cities such as Rio de Janeiro. During rainy seasons, Rio de Janeiro regularly suffered floods, as water from the bay surrounding the city overflowed into Rio's narrow streets. Coupled with the poor drainage systems found throughout Rio, this created swampy conditions in the city's neighborhoods. Pools of stagnant water stood year-long in city streets and proved to be fertile ground for disease-carrying mosquitoes. Thus, under Cruz's direction, public health units known as "mosquito inspectors" fiercely worked to combat yellow fever throughout Rio by spraying, exterminating rats, improving drainage, and destroying unsanitary housing. Ultimately, the city's sanitation and renovation campaigns reshaped Rio de Janeiro's neighborhoods. Its poor residents were pushed from city centers to Rio's suburbs, or to towns found in the outskirts of the city. In later years, Rio's most impoverished inhabitants would come to reside in
favelas. During 1920–1923, the
Rockefeller Foundation's
International Health Board undertook an expensive and successful yellow fever eradication campaign in Mexico. The IHB gained the respect of Mexico's federal government because of the success. The eradication of yellow fever strengthened the relationship between the US and Mexico, which had not been very good in the years prior. The eradication of yellow fever was also a major step toward better global health. In 1927, scientists isolated the Yellow fever virus in West Africa. Following this, two
vaccines were developed in the 1930s.
Max Theiler led the completion of the 17D
yellow fever vaccine in 1937, for which he was subsequently awarded the
Nobel Prize in Physiology or Medicine. That vaccine, 17D, is still in use, although newer vaccines, based on
vero cells, are in development (as of 2018). File:Juan Manuel Blanes Episodio de la Fiebre Amarilla.jpg|A painting by
Juan Manuel Blanes depicting
yellow fever in Buenos Aires, 1871 File:Finlay Carlos 1833-1915.jpg|
Carlos Finlay File:WalterReed.jpeg|
Walter Reed File:Max Theiler nobel.jpg|
Max Theiler Current status Using vector control and strict vaccination programs, the urban cycle of yellow fever was nearly eradicated from South America. Since 1943, only a single urban outbreak in
Santa Cruz de la Sierra, Bolivia, has occurred. Since the 1980s, however, the number of yellow fever cases has been increasing again, and
A. aegypti has returned to the urban centers of South America. This is partly due to limitations on available insecticides, as well as habitat dislocations caused by climate change. It is also because the vector control program was abandoned. Although no new urban cycle has yet been established, scientists believe this could happen again at any point. An outbreak in
Paraguay in 2008 was thought to be urban in nature, but this ultimately proved not to be the case. These programs have largely been unsuccessful because they were unable to break the
sylvatic cycle involving wild primates. With few countries establishing regular vaccination programs, measures to fight yellow fever have been neglected, making the future spread of the virus more likely. ==Research==