- Reason for surveillance
- Case definition
- Notification criteria and procedure
- The disease
- Managing single notifications
1. Reason for surveillance
To identify cases, their source of infection and to prevent further transmission.
2. Case definition
A probable case requires:
- Laboratory suggestive evidence, and
- Clinical evidence, and
- Epidemiological evidence.
Laboratory suggestive evidence
- Isolation of virus pending confirmation by CDC, Atlanta or NIV, Johannesburg, or
- Detection of specific virus by NAT, antigen detection assay, or electron microscopy pending confirmation by CDC, Atlanta or NIV, Johannesburg, or
- IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to specific virus pending confirmation by CDC, Atlanta or NIV, Johannesburg, or
- Detection of IgM to a specific virus.
A compatible clinical illness as determined by an infectious disease physician. Common presenting complaints are fever, myalgia, and prostration, with headache, pharyngitis, conjunctival injection, flushing, and gastrointestinal symptoms. This may be complicated by spontaneous bleeding, petechiae, hypotension, and perhaps shock, oedema and neurologic involvement.
- History of travel to an endemic/epidemic area within 9 days (Marburg), 13 days (Crimean Congo) or 21 days (Lassa, Ebola) of illness onset. Filoviruses are endemic in Sub-Saharan Africa, Lassa in Western Africa, Crimean Congo in Africa and the Middle East to West China, or
- Contact with a confirmed case, or
- Exposure to VHF-infected blood or tissues.
A confirmed case requires laboratory definitive evidence.
Laboratory definitive evidence
Laboratory definitive evidence requires confirmation by the Special Pathogens Laboratory, CDC, Atlanta, or the Special Pathogens Laboratory, National Institute of Virology (NIV), Johannesburg.
- Isolation of a viral haemorrhagic virus, or
- Detection of specific virus by NAT, antigen detection assay, or electron microscopy, or
- IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to specific virus.
Factors to be considered in case identification
Testing is available through the Institute of Clinical Pathology and Medical Research, Westmead Hospital.
3. Notification criteria and procedure
Viral haemorrhagic fevers are to be notified by:
- Hospital CEOs on diagnosis (ideal reporting by telephone within 1hour of diagnosis)
- Laboratories on diagnosis (ideal reporting by telephone within 1 hour of diagnosis).
Probable and confirmed cases should be entered onto NDD.
Note that viral haemorrhagic fevers are subject to the Commonwealth Quarantine Act 1908.
4. The disease
Important agents are Lassa fever virus (Arenavirus), Ebola virus, Marburg virus (Filoviradae) and Crimean-Congo haemorrhagic fever virus.
Mode of transmission
Mode of transmission depends on the particular virus, but in Australia (in the absence of enzootic cycles) is likely to be through exposure to blood and body fluids of infected persons.
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See Section 2. Case definition.
5. Managing single notifications
Immediately on notification, begin the follow-up investigation and notify the Communicable Diseases Branch. Refer to the NSW Health Guideline (GL2016_02) NSW Contingency Plan for Viral Haemorrhagic Fevers.
Within 1 working day of notification enter on NDD probable and confirmed cases only.
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 likely source of infection
- Ensure proper control measures are in place.
Investigation and treatment
Identify the source of the infection, including details of travel and exposures to potentially infectious sources.
The case or relevant care-giver should be informed about the nature of the infection and the mode of transmission, including the likelihood of sexual transmission (for Marburg and Ebola fevers).
Isolation and restriction
Institute isolation procedures in accordance with the NSW Health Guideline (GL2016_02) NSW Contingency Plan for Viral Haemorrhagic Fevers. Investigate transfer of the patient to the VHF Treatment Facility, Westmead.
None usually required. In the case of Rift Valley fever, notify NSW Agriculture immediately.
Identification of contacts
Contacts are defined as persons living with, caring for, testing laboratory specimens from, or having close contact with the case during the incubation period.
High risk contacts
High risk contacts have experienced definite percutaneous or permucosal exposure (for example needle stick injury, body fluid contact with mucosal surfaces or broken skin).
Medium risk contacts
Medium risk contacts have a high possibility of percutaneous or permucosal exposure (for example body fluids contact on intact skin, close face-to-face exposure without a mask, exposure to large volume of body fluids on protective clothing).
Low risk contacts
Low risk contacts have a low possibility of percutaneous or permucosal exposure (for example exposure to small volumes of body fluids on protective clothing, touched patient without gloves, handled specimen/cleaning without gloves).
Aerosol exposure risk only
Examples of aerosol exposure risk include handling unsealed specimens, cleaning room without a mask and being in the same room without a mask, but not having physical contact with the case.
Investigation and treatment
Contacts should be placed under surveillance for the duration of the incubation period since last exposure.
Advise susceptible contacts (or parents/guardians) of the risk of infection and the reason for and duration of quarantine. Blood must not be donated.
Isolation and restriction
Contacts may be quarantined. They may be released under quarantine surveillance for up to 3 weeks during which they are required to notify a Human Biosecurity Officer if suffering from a febrile illness. Public health units should initiate active daily surveillance at least for high and medium risk contacts.