An acute viral hemorrhagic disease, yellow fever is an infectious disease transmitted by the bite of female mosquitoes (Aedes aegypti and other species) with primates and several species of mosquitoes as the only known hosts. The disease is said to originate from Africa, reaching parts of South America through slave trade in the 16th Century.
The disease begins after an incubation period of three to six days. In most cases, yellow fever symptoms include fever, nausea, and pains that generally subside several days later. A dangerous toxic phase may take place in some patients (around 15% of cases recorded) wherein liver damage noticeable with jaundice can be observed. Jaundice is the yellowing of the skin and the white parts of the eyeball brought about by the accumulation of bile pigment in the blood. This is where the "yellow fever" name for the disease comes from. Moreover, yellow fever also gives rise to increased bleeding tendency and abdominal pain. There may also be bleeding in the gastrointestinal tract and some orifices. Mortality rate for those who enter the toxic phase is 20%.
Yellow fever's fatality rate is estimated at 3%. Those who survive the disease develop lifelong immunity and normally, no permanent organ damage follows. Vaccines for the disease exist but there is no known causative cure.