Yellow fever

Yellow fever usually takes 3 to 6 days to appear.

It begins as a mild illness, characterised by:

• fever
• muscle pain
• nausea
• vomiting
• headache
• weakness.

Around 15 to 25 per cent of those with yellow fever infection progress to a second ‘toxic’ stage, of which half die within 10 to 14 days after onset of illness.

Visible bleeding, jaundice, kidney and liver failure can occur during the second stage.

Yellow fever is transmitted to humans by the bite of infected mosquitoes, principally, Aedes and Haemagogus mosquito species.

The disease occurs in two forms – urban (household) and sylvatic (jungle) yellow fever. Both forms are caused by the same virus. In tropical rainforests, yellow fever occurs in monkeys that are infected by mosquitoes. The yellow fever virus is passed onto other mosquitoes that feed on infected monkeys. These infected mosquitoes bite humans that enter the forest, resulting in some cases of yellow fever. This form of the disease is known as ‘sylvatic’ or ‘jungle’ yellow fever.

People who travel to high risk areas such as Africa and South America

The World Health Organisation (WHO) provides a list of yellow fever declared places (external site) which includes 43 countries.

Yellow fever is preventable through vaccination (from 9 months of age).

The period of protection has changed from 10 years to the duration of the life of the person vaccinated. This is based on data demonstrating for the majority of people, a single dose of yellow fever vaccine results in life-long immunity.

The vaccine is safe and offers 90 per cent protection in 14 days and almost 100 per cent protection in 28 days

With few exceptions, vaccination is recommended for all travellers to countries or areas where there is a high risk of yellow fever transmission.

Check the list of yellow fever vaccination centres (external link) for your closest centre.

Vaccination is not recommended if travelling to areas where there is low risk of exposure to yellow fever, check the WHO list of yellow fever declared places (external site)

The mosquitoes that transmit yellow fever are usually active during the day, when travelling to high risk areas:

• wear a mosquito repellent containing DEET or Picaridin
• wear light coloured, long-sleeved clothes when you’re outdoors
• avoid wearing perfume or cologne, because these can attract mosquitoes
• prevent mosquitoes entering your accommodation by keeping doors/fly screens closed
• use a mosquito net at night if mosquitoes are likely to be present

See your doctor or go to your local hospital if you have travelled to any high risk country and suspect that you have symptoms of yellow fever.

Diagnosis is made through a blood test

Notifiable disease

Yellow fever is a notifiable disease. This means doctors, hospitals and laboratories must inform the Department of Health of your diagnosis. Notification is confidential.

Department of Health staff may talk to you or your doctor to find out travel history and how the infection occurred, and to advise you if you need to stay away from work, school or other group gatherings.

There is no specific treatment for yellow fever, and 50% of severely affected persons will die. However medicines can be used to relieve the symptoms and may improve the outcome for seriously ill patients.