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 10 years. Although the WHO on 17 May 2013 advised that subsequent booster vaccinations are unnecessary, an older (than 10 years) certificate may not be acceptable at all border posts in all affected countries. A list of the countries that require yellow fever vaccination is published by the WHO. If the vaccination cannot be conducted for some reasons, dispensation may be possible. In this case, an exemption certificate issued by a WHO-approved vaccination center is required. Although 32 of 44 countries where yellow fever occurs endemically do have vaccination programmes, in many of these countries, less than 50% of their