A jaundice, or virus, known as a flavivirus, it is transmitted to humans through the bite of infected mosquitoes. People get yellow fever from the bite of an infected female mosquito which injects the yellow fever virus into the skin.

Illness ranges in severity from a self-limited febrile illness to severe hepatitis and hemorrhagic fever.

Yellow fever disease is diagnosed based on symptoms, physical findings, laboratory testing, and the possibility of exposure to infected mosquitoes. There is no specific treatment for yellow fever; care is based on which symptoms caused it.

Steps to prevent yellow fever include use of insect repellent, protective clothing, and vaccination. Yellow fever occurs primarily in tropical regions of Africa and in parts of South America; however, it is a very rare cause of illness in U.S. travelers. The last epidemic of yellow fever in North America occurred in New Orleans in 1905.