yellow fever

Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains—particularly in the back—and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever recurs, abdominal pain occurs and liver damage begins, causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased.

The disease is caused by the yellow fever virus and is spread by the bite of an infected mosquito. It infects humans, other primates, and several types of mosquitoes. In cities, it is spread primarily by Aedes aegypti, a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus Orthoflavivirus (full scientific name Orthoflavivirus flavi). The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood-sample testing with a polymerase chain reaction is required.