Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. One of the most dangerous viral illnesses is the yellow fever, an acute viral hemorrhagic disease, transmitted by the bite of a female yellow fever mosquito, Aedes aegypti, found in tropical and subtropical areas in South America and Africa. The World Health Organisation estimates that yellow fever causes 200,000 illnesses and 30,000 deaths every year in unvaccinated populations with nearly 90% of the infections occuring in Africa. Since the 1980s, the number of cases of yellow fever has been increasing, making it a reemerging disease, likely due to warfare and social disruption in several African nations. Learn more about the yellow fever, its life-cycle and transmission, as well as symptoms, cures and vaccines of the deadly disease it causes in the following pages.