Yellow fever

Definition:

An insect-borne tropical disease characterized by fever, jaundice (yellow skin and eyes), and hemorrhage.

Causes, incidence, and risk factors:

Yellow fever is caused by an arbovirus (Flaviviridae), a small RNA virus that is transmitted by the bite of mosquitoes (Aedes aegypti, Aedes africanus, and Haemagogus). Areas of high incidence are Central America, the northern half of South America, and Central Africa.

Mild subclinical infection occurs and may be more common in children. The acute form of the disease causes headache, muscle aches, fever, loss of appetite, and vomiting. The infected person may also develop a red tongue, flushed face, and reddening of the eyes. By the fifth day, jaundice (the yellow color of the skin for which the disease is named), stomach pain, and bleeding (which may appear as bloody vomiting) develops. Delirium and seizures followed by coma are common. Death occurs at the end of the first week of symptoms and as many as half of the infected people may die.