Yellow fever is a viral disease that is transmitted to humans through the bite of infected mosquitoes. Yellow fever occurs worldwide, in tropical regions of Africa and in parts of South America, but travel-related cases are rarely reported in the United States. The last epidemic of yellow fever in North America occurred in New Orleans in 1905.
Onset of illness usually ranges from 3-6 days after being bitten by an infected mosquito. Symptoms of illness can be mild with acute onset of fever, chills, headache, muscle aches, and vomiting to severe hemorrhagic fever, kidney and liver failure. Yellow fever can be prevented by vaccination prior to traveling to endemic areas.