Yellow fever is a viral disease, caused by the yellow fever virus, and transmitted by female mosquitoes It is a tropical disease that results in the death of about half who develop severe cases that are left untreated. Symptoms include high fever, chills, nausea, loss of appetite, muscle pain and headaches. While a safe and effective vaccine against yellow fever exists, it still causes 200,000 infections and 30,000 deaths annually, most of them in Africa.
Yellow fever is endemic in tropical and subtropical regions of Africa and South America. It is believed to have originated in Africa, migrating to the New World alongside the slave trade. The first outbreak in the Americas occurred in Barbados in 1647. The disease was named "yellow fever" in 1744. Outbreaks in New York occurred in 1668, and in Philadelphia in 1669 and 1793. New Orleans was home to several major outbreaks of yellow fever in 1833 and 1853 being the most notorious. The last outbreak in the United States occurred in 1905, in New Orleans. Yellow fever was also rampant during the construction of the Panama Canal and during the Spanish-American War in Cuba.
In 1881, Cuban doctor Carlos Finlay first proposed the idea that yellow fever was transmitted by mosquito bites. A team of scientists led by Walter Reed later proved this hypothesis. Vaccines were developed in the 1903s after the virus was isolated in West Africa.