Yellow Fever

Yellow fever is a disease caused by a virus that is spread through mosquito bites. Yellow fever is found in areas in South America and Africa. For a complete list of countries where active yellow fever transmission is occurring, see list of affected areas.
  1. Transmission
  2. Signs & Symptoms
  3. Treatment
  4. Prevention
Yellow fever is spread primarily through mosquito bites. Yellow fever is spread to people primarily through the bite of infected Aedes aegypti mosquitoes. Aedes aegypti mosquitoes are found in Maricopa County and other parts of Arizona; however, we do not have mosquitoes infected with yellow fever. In Arizona, yellow fever infections have been found only in people who were infected while traveling outside the United States. These mosquitoes bite humans all day long so it is important to protect against mosquito bites whenever you are outside.