Public health priority: Urgent.
PHU response time: Respond to cases on day of notification.Enter confirmed cases on NDD within 1 working day.
Case management: Notify the Communicable Diseases Branch. Determine source of infection.
Contact management: Unimmunised contacts who shared an exposure with the case should be placed under surveillance.
Quarantine: Yellow fever is subject to the Commonwealth Quarantine Act (1908).
Last updated: 25 January 2013
1. Reason for surveillance
- To identify cases and prevent infection of mosquitoes in susceptible areas (e.g. Northern Queensland).
2. Case definition
Only a confirmed case should be notified.
A confirmed case requires either laboratory definative evidence AND cliinical evidence OR laboratory suggestive evidence AND clinical AND epidemilogical evidence.
Laboratory definitive evidence
- Isolation of yellow fever virus OR
- Detection of yellow fever virus by necleic acid testing OR
- Seroconversion or a four-fold or greater rise in yellow fever virus-specific serum IgM or IgG levels between acute and convalescent samples in the absence of vaccination in the preceding 3 weeks OR
- Detection of yellow fever virus antigen in tissues by immunohistochemistry
Laboratory suggestive evidence
- Yellow fever virus-specific IgM detected in the absence of IgM to other relevant flaviviruses, in the absence of vaccination in the preceeding 3 months.
Confirmation of laboratory results by a second arbovirus reference laboratory is required in the absence of travel history to areas with known endemic or epidemic activity.
A clinically compatible illness.
History of travel to a yellow fever endemic country in the week preceding onset of illness.
3. Notification criteria and procedure
Yellow fever is to be notified by:
- Hospital CEOs on diagnosis (ideal reporting by telephone within 1 hour of diagnosis)
- Laboratories on diagnosis (ideal reporting by telephone within 1 hour of diagnosis).
Only confirmed cases should be entered onto NDD. Yellow fever is subject to the Commonwealth Quarantine Act (1908).
4. The disease
The Yellow Fever virus, a Flavivirus.
Mode of transmission
Urban yellow fever is transmitted from person to person by the Aedes aegypti mosquito. Jungle yellow fever is a zoonosis transmitted among non-human hosts (mainly monkeys) by various forest mosquitoes that may also bite and infect humans. Aedes aegypti do not live in NSW. Rarely, yellow fever can follow as an idiosyncratic reaction to the yellow fever vaccination.
The typical incubation period is 3 to 6 days. The blood of cases is infective for mosquitoes shortly before onset of fever and up to five days after onset.
The usual clinical presentation is as an acute viral disease of short duration and varying severity. The mildest cases are clinically indeterminate; typical attacks are characterised by sudden onset, fever, chills, headache, backache, generalised muscle pain, prostration, nausea and vomiting. The classic triad of jaundice, haemorrhage and pronounced albuminuria is present only in a small number of severe cases.
5. Managing single notifications
On same day of notification begin follow-up investigation and notify the Communicable Disease Branch of the details of the case.
Within 1 working day of notification enter confirmed cases on NDD.
The response to a notification will normally be carried out in collaboration with the case's health carers. But regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
- Confirm the onset date and symptoms of the illness
- Confirm results of relevant pathology tests, or recommend the tests be done
- Find out if the case or relevant care-giver has been told what the diagnosis is before beginning the interview
- Seek the doctor's permission to contact the case or relevant care-giver
- Identify the likely source of infection and ensure proper control measures are in place.
Investigation and treatment
Identify the source of the infection, such as a location visited and exposures during recent overseas travel, and vaccination history.
The case or relevant care-giver should be informed about the nature of the infection and the mode of transmission and the reason for and duration of quarantine.
Isolation and restriction
Standard precautions. Prevent access to the patient by mosquitoes for ≥5 days after onset (care for case in a screened room, or using a mosquito net and insect spray).
None usually required.
Identification of contacts
Any unimmunised person who has travelled through a yellow fever-endemic country with the case.
Identification of contacts
Contacts should be placed under surveillance.
Advise susceptible contacts (or parents/guardians) of the risk of infection and the reason for and duration of quarantine.
Isolation and restriction
Unimmunised travellers are routinely placed under quarantine surveillance on entry into Australia by Australian Quarantine and Inspection Service officers for 6 days since last staying over night in a country where yellow fever may be present. During this period they are required to notify the Chief Quarantine Medical Officer if suffering from a febrile illness.