This article was published in Communicable Diseases Intelligence Vol 35 Number 2, June 2011 and may be downloaded as a full version PDF file (1854 KB).
Notes on interpretation
The present report is based on 2009 ‘finalised’ data from each state or territory agreed upon in July 2010 and represents a snap shot of the year after duplicate records and incorrect or incomplete data were removed. Therefore, numbers in this report may vary slightly from the numbers reported in CDI quarterly publications.
Analyses in this report were based on the date of disease diagnosis in an attempt to estimate disease activity within the reporting period. The date of diagnosis is the onset date or where the date of onset was not known, the earliest of the specimen collection date, the notification date, or the notification receive date. As considerable time may have elapsed between the onset and diagnosis dates for hepatitis B (unspecified), hepatitis C (unspecified) and tuberculosis, the earliest of specimen date, health professional notification date or public health unit notification receive date was used for these conditions.
Notified cases often represent a proportion (the ‘notified fraction’) of the total incidence (Figure 1) and this has to be taken into account when interpreting NNDSS data. Moreover, the notified fraction varies by disease, by jurisdiction and by time.
Figure 1: Communicable diseases notifiable fraction
Methods of surveillance vary between states and territories, each having different requirements for notification by medical practitioners, laboratories and hospitals. Although the National Notifiable Diseases List2 was established, some diseases are not yet notifiable in all 8 jurisdictions (Table 2).
Table 2: Diseases notified to the National Notifiable Diseases Surveillance System, Australia, 2009
Data received from
|Hepatitis (NEC)||All jurisdictions, except Western Australia|
|Hepatitis B (newly acquired)||All jurisdictions|
|Hepatitis B (unspecified)||All jurisdictions|
|Hepatitis C (newly acquired)||All jurisdictions, except Queensland|
|Hepatitis C (unspecified)||All jurisdictions|
|Hepatitis D||All jurisdictions|
|Campylobacteriosis||All jurisdictions, except New South Wales|
|Haemolytic uraemic syndrome||All jurisdictions|
|Hepatitis A||All jurisdictions|
|Hepatitis E||All jurisdictions|
|STEC, VTEC*||All jurisdictions|
|Highly pathogenic avian influenza in humans||All jurisdictions|
|Severe acute respiratory syndrome||All jurisdictions|
|Viral haemorrhagic fever||All jurisdictions|
|Yellow fever||All jurisdictions|
Sexually transmissible infections
|Chlamydial infections||All jurisdictions|
|Gonococcal infection||All jurisdictions|
|Syphilis < 2 years duration||All jurisdictions|
|Syphilis > 2 years or unspecified duration||All jurisdictions, except South Australia|
|Syphilis – congenital||All jurisdictions|
Vaccine preventable diseases
|Haemophilus influenzae type b||All jurisdictions|
|Influenza (laboratory confirmed)||All jurisdictions|
|Pneumococcal disease (invasive)||All jurisdictions|
|Rubella – congenital||All jurisdictions|
|Varicella zoster (chickenpox)||All jurisdictions, except NSW|
|Varicella zoster (shingles)||All jurisdictions, except NSW|
|Varicella zoster (unspecified)||All jurisdictions, except NSW|
|Arbovirus infection (NEC)||All jurisdictions|
|Barmah Forest virus infection||All jurisdictions|
|Dengue virus infection||All jurisdictions|
|Japanese encephalitis virus infection||All jurisdictions|
|Kunjin virus infection||All jurisdictions|
|Murray Valley encephalitis virus infection||All jurisdictions|
|Ross River virus infection||All jurisdictions|
|Australian bat lyssavirus||All jurisdictions|
|Lyssavirus (NEC)||All jurisdictions|
|Q fever||All jurisdictions|
Other bacterial infections
|Meningococcal disease (invasive)||All jurisdictions|
No new diseases were added to the disease list in 2009.
* Infection with Shiga toxin/verotoxin-producing Escherichia coli (STEC/VTEC).
NEC Not elsewhere classified.
Changes in surveillance practices may have been introduced in some jurisdictions and not in others, and makes the comparison of data across jurisdictions difficult. In this report, some information was obtained from states and territories, including changes in surveillance practices, screening practices, laboratory practices, and major disease control or prevention initiatives to assist in the interpretation of the 2009 data.
Postcode information usually reflects the residential location of the case, but this does not necessarily represent the place where the disease was acquired. In December 2008, the CDNA endorsed the NNDSS cross-border notification protocol, which determines that the jurisdiction of residence of a case has the responsibility of reporting the notification to NNDSS. This was implemented from 1 January 2009, and may also affect some retrospective notifications by removing duplicates and preventing the loss of notification data in NNDSS.
Data completeness was assessed for the notification’s sex, age at onset, and Indigenous status, and reported as the proportion of complete notifications. The completenessof data in this report is summarised in the Results.
The per cent of data completeness was defined as:
Per cent of data completeness = (total notifications – missing or unknown) / total notifications x 100
The Indigenous status was defined by the following nationally accepted values:10
1=Indigenous – (Aboriginal but not Torres Strait Islander origin)
2=Indigenous – (Torres Strait Islander but not Aboriginal origin)
3=Indigenous – (Aboriginal and Torres Strait Islander origin)
4=Not Indigenous – (not Aboriginal or Torres Strait Islander origin)
Notes on cases definitions
Each notifiable disease is governed by a national surveillance case definition for reporting to the NNDSS. These case definitions were agreed by CDNA and implemented nationally from January 2004 and were used by all jurisdictions for the first time in 2005. These case definitions are reviewed by the Case Definitions Working Group (CDWG) and seeks to be consistent with the Public Health Laboratory Network laboratory case definitions.
The national surveillance case definitions and their review status are available from http://www.health.gov.au/casedefinitions
This issue - Vol 35 No 2, June 2011
NNDSS Annual report 2009