What is the disease?
Yellow fever is a viral disease transmitted to humans by infected mosquitoes in parts of South America and Africa.
What are the symptoms?
Symptoms of infection include a sudden onset of fever, chills, muscle pain, backache, headache, nausea and vomiting three to six days after the virus enters the body. After three to four days most patients improve and their symptoms disappear.
However, about 15% of patients will go on to have bleeding (from the mouth, nose and eyes and/or stomach), jaundice (yellowing of the skin and eyes), abdominal pain with vomiting and problems with kidney function. Half of these patients recover but the remaining half die within 10-14 days of developing these symptoms.
How is it spread?
Humans and monkeys are the main animals infected by the virus. A certain type of mosquito (known as Aedes aegypti) is the main vector to transmit the virus. It takes three to six days for the illness to begin once a person is bitten by an infected mosquito.
Infected people can transmit the infection to mosquitoes for up to five days after the onset of symptoms. The infection is not spread directly from person to person or from animal to person.
Who is at risk?
Yellow fever only occurs in certain parts of Africa and South America. Unimmunised travellers to, and people living in these areas are at risk of infection.
How is it prevented?
Vaccination is the most effective way to prevent yellow fever:
- Yellow fever vaccination must be administered at a clinic designated as an approved yellow fever vaccination centre and this must be recorded on an International yellow fever vaccination certificate. See the NSW Health Yellow fever vaccination information for a list of approved yellow fever vaccination centres.
- a single Yellow fever vaccination is now considered to provide life-long protection (previously a booster vaccination had been recommended every 10 years)
- all people aged one year or older who have stayed overnight or longer in a declared Yellow fever infected country within the six days prior to their arrival Australia are required to show evidence of having had a yellow fever vaccination which is documented on an approved international yellow fever vaccination certificate. For more information and for a list of Yellow Fever-declared countries see the Australian Government Department of Health Yellow fever website .
- other countries may refuse entry to any person without a valid Yellow fever vaccination certificate who has recently been in a yellow fever infected country, and some of these may only allow unvaccinated people to enter after they are vaccinated at their border. The safety of the vaccine given in such situations cannot be guaranteed.
Even if you have been vaccinated it is still important to protect against mosquitoes and reduce the risk of diseases they transmit:
- cover-up with a loose-fitting long sleeved shirt and long pants when outside
- apply mosquito repellent to exposed skin
- remove potential mosquito breeding sites from around the home and screen windows and doors
- take extra precautions when travelling in areas with a higher risk of mosquito-borne diseases.
In addition to the general protection measures above, overseas travellers should also:
- take special care during peak mosquito biting hours. The mosquitoes that transmit diseases such as yellow fever, dengue, chikungunya and Zika will bite all through the day
- stay and sleep in screened or air-conditioned rooms
- use a bed net if the area where you are sleeping is exposed to the outdoors. Nets are most effective when they are treated with a pyrethroid insecticide, such as permethrin. Pre-treated bed nets can be purchased before travelling, or nets can be treated after purchase
- avoid known areas of high mosquito-borne disease transmission or outbreaks.
For more detailed Yellow fever vaccination advice, see the Australian Immunisation Handbook and consult with your GP or travel medicine clinic.
For more detailed information on reducing the risk of mosquito bites at home and while travelling, see the Mosquitoes are a Health Hazard factsheet. This also includes more information on mosquito repellents.
See the Staying healthy when travelling overseas factsheet for further information on travel. The Smart Traveller website also has health information for specific destinations.
How is it diagnosed?
Yellow fever is difficult to recognise in its early stages as there are a number of infections that may have similar signs and symptoms. Diagnosis requires a blood test.
How is it treated?
There is no specific treatment for Yellow fever. Patients can be treated for dehydration and fever. Intensive care may be needed for seriously ill patients.
In areas in which the Aedes aegypti mosquito lives (such as North Queensland), patients should be cared for in mosquito-proof rooms.
What is the public health response?
Laboratories and hospitals are required to notify cases of Yellow fever to the local public health unit. Public health units investigate possible cases to identify the risk factors for the disease and prevent infection of mosquitoes in susceptible areas in Australia.
For further information please call your local public health unit on 1300 066 055.
For further information on Australian and international Yellow fever vaccination certificate requirements see the Australian Department of Health Yellow fever fact sheet page.