This report provides the revised Surveillance case definitions approved by the Communicable Diseases Network Australia (CDNA) since 1 July 2014.

The Case Definitions Working Group (CDWG) is a subcommittee of the CDNA and comprises members representing all states and territories, the Australian Government Department of Health, the Public Health Laboratory Network, OzFoodNet, the Kirby Institute, the National Centre for Immunisation Research and Surveillance and other communicable disease experts. CDWG develops and revises surveillance case definitions for all diseases reported to the National Notifiable Diseases Surveillance System. Surveillance case definitions incorporate laboratory, clinical and epidemiological elements as appropriate.

The following case definitions have been reviewed by CDWG and endorsed by CDNA.

These case definitions were implemented on 1 January 2015 and supersede any previous versions.

Hepatitis C – newly acquired

Reporting

Only confirmed cases should be notified.

Confirmed case

A confirmed case requires either:

Laboratory definitive evidence

OR

Laboratory suggestive evidence AND clinical evidence.

Laboratory definitive evidence

Detection of anti-hepatitis C antibody from a person who has had a negative anti-hepatitis C antibody test recorded within the past 24 months

OR

Detection of hepatitis C virus by nucleic acid testing from a person who has a negative anti-hepatitis C antibody test result currently, or has had, within the past 24 months.

OR

Detection of anti-hepatitis C antibody from a child aged 18 months to 24 months

OR

Detection of hepatitis C virus by nucleic acid testing in a child aged 3 months to 24 months.

Laboratory suggestive evidence

Detection of anti-hepatitis C antibody, or hepatitis C virus by nucleic acid testing in a patient with no prior evidence of hepatitis C infection.

Clinical evidence

Clinical hepatitis within the past 24 months (where other causes of acute hepatitis have been excluded) defined as

Jaundice

OR

Bilirubin in urine

OR

Alanine transaminase (ALT) ten times upper limit of normal.

Hepatitis C – newly acquired

Hepatitis C – newly acquired	Laboratory suggestive evidence Added ‘…in a patient with no prior evidence of hepatitis C infection.’ Clinical evidence Changed Alanine transaminase (ALT) from seven to ten times upper limit of normal.

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Viral haemorrhagic fevers (quarantinable)

(Quarantinable – includes Ebola, Marburg, Lassa and Crimean-Congo fevers)

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires laboratory definitive evidence only.

Laboratory definitive evidence

Laboratory definitive evidence requires confirmation by the Victorian Infectious Diseases Reference Laboratory (VIDRL), Melbourne or the Special Pathogens Laboratory, CDC, Atlanta, or the Special Pathogens Laboratory, National Institute of Virology (NIV), Johannesburg

Isolation of a specific virus

OR

Detection of specific virus by nucleic acid testing or antigen detection assay

OR

IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to specific virus.

Probable case

A probable case requires laboratory suggestive evidence AND clinical evidence AND epidemiological evidence.

Laboratory suggestive evidence

Isolation of virus pending confirmation by VIDRL, Melbourne, or CDC, Atlanta or NIV, Johannesburg

OR

Detection of specific virus by nucleic acid testing, pending confirmation by VIDRL, Melbourne, or 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 VIDRL, Melbourne, or CDC, Atlanta or NIV, Johannesburg

OR

Detection of IgM to a specific virus.

Clinical evidence

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, gastrointestinal symptoms. This may be complicated by spontaneous bleeding, petechiae, hypotension and perhaps shock, oedema and neurologic involvement.

Epidemiological evidence

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 viral haemorrhagic fever-infected blood or tissues.

Viral haemorrhagic fevers (quarantinable)

The first case in any outbreak in Australia will also be confirmed by CDC, Atlanta or NIV, Johannesburg..
Viral haemorrhagic fevers (quarantinable)	Laboratory definitive evidence Include the Victorian Infectious Diseases Reference Laboratory (VIDRL) as an additional laboratory where laboratory definitive evidence can be confirmed. Include footnote that the first case in Australia in any given outbreak will also be confirmed by CDC or NIV.

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