History of yellow fever 1,235 fatalities were recorded of an estimated 12,000 cases. Smaller outbreaks occurred in Saint-Nazaire in France, Swansea in Wales, and in other European port cities following the arrival of vessels carrying the mosquito vector. The first mention of the disease by the name "yellow fever" occurred in 1744. Many famous people, mostly during the 18th through the 20th centuries, contracted and then recovered from, or died of, yellow fever. The Yellow Fever Epidemic of 1793 struck during the summer in Philadelphia, Pennsylvania, where the highest fatalities in the United States were recorded. The disease probably was brought by refugees and
Yellow fever 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 was endemic in Africa, the natives had developed some immunity to it. When an outbreak of yellow fever would occur in an African village where colonists resided, most Europeans died, while the native population usually suffered nonlethal symptoms resembling influenza. This phenomenon, in which certain populations develop immunity to yellow fever due to prolonged exposure in their childhood, is known as acquired immunity. The virus, as well as the vector "A. aegypti," were