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Yellow Fever Profiles


The virus has an incubation period of 3-6 days.


The mosquito is the yellow fever virus, so transmission occurs via mosquito bites. The virus is also preserved in mosquito eggs through their incubation period, thus ensuring existence of the virus each year. Yellow fever is located only in Africa and South America.




Global distribution of Yellow Fever, 1996 (CDC)

Symptomatology and outcome

Although some people experience no symptoms, others enter an acute phase, characterized by fever, muscle pain (especially backache), shivers, loss of appetite, nausea and/or vomiting. An indication of yellow fever infection is that the high fever is associated with a relatively slow pulse. After 3 or 4 days, most patients improve, but an estimated 15% enter a toxic phase, marked by a reappearance of fever, jaundice, abdominal pain, vomiting, and bleeding from the eyes, nose, mouth, vomit, and feces. Half of these patients in the toxic phase die within 10-14 days.

Prevention and management

A yellow fever vaccine is available and should be taken by travelers to endemic areas. It is a safe, effective live virus vaccine that has been used for several decades and confers immunity for 10 years or more. Side effects occur in very few vaccinees. Four groups of people should not receive the vaccine: infants under 6 months, pregant women, persons hypersensitive to eggs (the vaccine is developed in embryonic eggs), and immunosuppressed persons.

Because the virus is transmitted by mosquitos, effective protection against mosquitos results in effective potection against yellow fever. This includes the use of insect repellant, protective clothing, and mosquito netting.

Sources: CDC, WHO