What is it

Yellow fever is a viral disease spread by mosquitoes.1 It occurs in tropical and subtropical areas of Africa and South America.1 Its name is derived from the yellowing of the skin and eyes (jaundice) that occurs when the virus attacks the liver1. Illness ranges in severity from self-limited febrile cases to severe liver damage with bleeding.1

Who is at risk

Risk of developing yellow fever depends on several factors including1:

  • Travel destination
  • Time of the year (season)
  • Duration of travel
  • Activities done during the trip

Risk is higher for travellers who are going to areas of risk (e.g. tropical areas of Africa and South America) and who are staying for an extended period of time, visiting rural or jungle areas or participating in outdoor activities including camping, hiking cycling or fieldwork1.

What are the symptoms

Symptoms develop within 3 to 6 days1. Initial symptoms include1:

  • Sudden onset of fever
  • Chills
  • Headache
  • Joint and muscle pain
  • Loss of appetite
  • Abdominal pain, back pain
  • Nausea, vomiting
  • Fatigue, weakness
  • Dehydration

In severe cases yellow fever can cause1:

  • Shock
  • Internal bleeding
  • Jaundice (yellow of the skin and whites of the eyes)
  • Organ failure

How is it spread

Yellow fever is a viral disease that spread through the bite of infected mosquitoes, mainly the Aedes species in Africa and the Haemagogus species in South America1. Mosquitoes that spread yellow fever typically bite during the daytime, particularly around sunrise and sunset.1

How is it prevented

Consult your healthcare provider or visit a travel clinic (preferably six weeks or more) prior to travelling.2

To prevent getting sick from yellow fever, use insect repellent, wear long-sleeved shirts and long pants, and get vaccinated.3

Vaccine is recommended for people aged 9 months or older and who are traveling to or living in areas at risk for yellow fever virus in Africa and South America.3
Yellow fever vaccine may be required for entry into certain countries.3 

How is it treated

There is no specific treatment for yellow fever, only supportive care to relieve symptoms.1


  1. Government of Canada. Yellow Fever
  2. Ministry of Health Israel. Vaccination Abroad.
  3. Centers for Disease Control and Prevention. Yellow Fever.