History of yellow fever History of yellow fever The evolutionary origins of yellow fever most likely lie in Africa. Phylogenetic analyses indicate that the virus originated from East or Central Africa, with transmission between primates and humans, and spread from there to West Africa. The virus as well as the vector "Aedes aegypti", a mosquito species, were probably brought to the western hemisphere and the Americas by slave trade ships from Africa after the first European exploration in 1492. The first outbreaks of disease that were probably yellow fever occurred in the Windward Islands of the Caribbean on Barbados in 1647 and Guadalupe in
Yellow fever vaccine is a small risk of neurologic disease and encephalitis, particularly in individuals with compromised immune systems and very young children. The 17D vaccine is contraindicated in (among others) infants between zero and six months or over 59 years of age, people with thymus disorders associated with abnormal immune cell function, people with primary immunodeficiencies, and anyone with a diminished immune capacity including those taking immunosuppressant drugs. There is a small risk of more severe yellow fever-like disease associated with the vaccine. This reaction, called YEL-AVD, causes a fairly severe disease closely resembling yellow fever caused by virulent strains of the