Public Health and Communicable Diseases - SA Health - SA.Gov.au

The collection of notifiable disease data is facilitatedby the use of a standard notification form. Theseforms seek common core data that includes patientidentification, age, sex, Indigenous status, residentiallocation, date of onset and details of the reportingdoctor. Clinical judgment on the cause of disease,identification of risk factors and the occurrence of othercases are important elements in surveillance, whilelaboratory notification often enables links between casesto be established that could not be achieved by medicalnotification alone. For certain invasive and vaccinepreventable conditions such as Haemophilus influenzaeinfection, meningococcal disease, pneumococcaldisease and Q Fever, more detailed data collection isroutinely performed on each case’s clinical presentation,such as their risk factors and vaccination status.Analysis and dissemination of surveillance dataAnalysis of surveillance data focuses on differencesbetween observed and expected rates of disease orcounts of cases. CuSUM (Cumulative Sum) analysis 8is the main statistical technique used to examineNDDMS surveillance data. These calculations take intoaccount current and previous observations to identifywhen the rate of a notifiable condition exceeds anestablished baseline. CuSUMs are also calculated at thelocal government area (LGA) level allowing geographicand spatial analysis of disease clustering (Figure 3).Where indicated data are orientated by person, placeor time using epidemic curves to plot rates of diseasenotifications over time, while line listings and geospatialmapping provide visual displays of disease clustering.The timely dissemination of data to those who need toknow is crucial to effective surveillance. In SA weeklyupdates of surveillance information are posted onlinevia the CDCB Public Health webpage http://www.dh.sa.gov.au/pehs/notifiable-diseases-summary/currentepi-features.htmIncluded are the current week’sepidemiological features, information on influenza andother respiratory illnesses, notification summaries, yearto date totals for notifiable conditions and a summary ofall outbreaks investigated in SA. Along with the otherstates and territories, SA then contributes a core set ofnotifiable disease data to the Commonwealth for thepurposes of national disease surveillance.ConclusionInformation derived from public health surveillanceguides public health practice. The passive reportingof notifiable conditions through the NDDMS willcontinue to provide the basis for communicable diseasemonitoring and intervention in SA. While this approachcan be considered as meeting current needs, thechanging epidemiology of communicable diseases isleading to a renaissance in surveillance techniques. Inorder to ensure sustainable, comprehensive and timelycollection of high quality public health data increasingrigour is being applied to surveillance practices throughimproved statistical analysis, more frequent evaluationand the use of web-based systems for data collectionand dissemination. The key challenge will be forgovernment to recognise that surveillance practicesneed to be every bit as dynamic as the pathogens theyseek to detect and prevent.Figure 3: Map of RRV cases by source of infection July 2005 - May 2006