Yellow fever

Yellow fever is a viral disease transmitted to humans by mosquitoes in parts of South America and Africa.

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.

• Humans and monkeys are the main animals infected by the virus.

• Certain species of mosquitoes known as Aedes aegypti are required to spread 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 animal to person.

Yellow fever only occurs in Africa and South America in countries located near the equator.

Vaccination is the most effective way to prevent yellow fever.

• Vaccination must be administered at an approved vaccination centre and an international yellow fever vaccination certificate must be provided. Your local public health unit can provide a list of approved vaccination centres.

• Under the Commonwealth Quarantine Act, 1908, any person over one year of age must hold an international yellow fever vaccination certificate if they have stayed overnight or longer in a declared yellow fever infected country within the six days prior to their arrival in Australia. A list of yellow fever declared countries can be found at: http://www.health.gov.au/internet/wcms/publishing.nsf/content/health-pubhlth-strateg-communic-factsheets-yellow.htm.

• 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 sterility of the vaccine given in such situations may not always be guaranteed.

• Persons arriving in Australia from a yellow fever infected country without a yellow fever vaccination certificate will be interviewed on their arrival by officers from the Australian Quarantine Inspection Service (AQIS). AQIS officers may only permit unvaccinated people to enter Australia if they agree in writing to notify health authorities if they develop any symptom of yellow fever infection in the six-day period following their departure from a declared yellow fever infected place.

Travellers in yellow fever infected countries should also take measures to avoid being bitten by mosquitoes:

• Wear loose fitting, long sleeved clothing

• Apply mosquito repellent (containing DEET or picardin) to exposed areas

• Stay in mosquito proof accommodation (e.g. use bed nets).

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.

• 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.

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 the infection of mosquitoes in susceptible areas in Australia.

For more information, please contact your doctor, local public health unit or community health centre.