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
1793 Philadelphia yellow fever epidemic vector of the 1793 plague in Philadelphia (and other Atlantic ports) was the British merchant ship "Hankey", which had fled the West African colony of Bolama (an island off West Africa, present day Guinea-Bissau) the previous November, trailing yellow fever at every port of call in the Caribbean and eastern Atlantic seaboard. See: "The Ship of Death: The Voyage That Changed the Atlantic World". After two weeks and an increasing number of fever cases, Dr. Benjamin Rush, a doctor's apprentice during the city's 1762 yellow fever epidemic, saw the pattern; he recognized that yellow fever had returned. Rush alerted his