Yellow fever 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. Although yellow fever is most prevalent in tropical-like climates, the northern United States were not exempted from the fever. The first outbreak in English-speaking North America occurred in New York City in 1668, and a serious one afflicted Philadelphia in 1793. English colonists in Philadelphia and the French in the Mississippi River Valley recorded major outbreaks in 1669, as well as those occurring later in
Yellow fever vaccine fever certificate of vaccination for travelers. Increases in cases of yellow fever in endemic areas of Africa and South America in the 1980s were addressed by the WHO Yellow Fever Initiative launched in the mid-2000s. The initiative was supported by the Gavi Alliance, a collaboration of the WHO, UNICEF, vaccine manufacturers, and private philanthropists such as the Bill & Melinda Gates Foundation. Gavi-supported vaccination campaigns since 2011 have covered 88 million people in 14 countries considered at "high-risk" of a yellow fever outbreak (Angola was considered "medium risk"). Activities of the Yellow Fever Initiative are managed through an international coordinating