Australian national notifiable diseases case definitions

Influenza laboratory-confirmed

This document contains the case definitions for Influenza which is nationally notifiable within Australia. This definition should be used to determine whether a case should be notified.

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Surveillance case definition

Version	Summary of changes	Last reviewed	Implementation date
1.1	In Laboratory definitive evidence under point 3. add Laboratory in front of 'Detection of influenza …' to read 'Laboratory detection of influenza …'.	14 August 2008	29 October 2008
1.0	Initial case definition	2004	2004

Reporting

Only confirmed cases should be notified.

Confirmed cases

A confirmed case requires laboratory definitive evidence only.

Laboratory definitive evidence

1.    Isolation of influenza virus by culture from appropriate respiratory tract specimen

OR

2.    Detection of influenza virus by nucleic acid testing from appropriate respiratory tract specimen

OR

3.    Laboratory detection of influenza virus antigen from appropriate respiratory tract specimen

OR

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

OR

5.    Single high titre by CFT or HAI to influenza virus.