Medical practitioners and microbiological laboratories are obliged by the Public and Environmental Health Act, 1987, to notify cases suspected of having notifiable diseases and all notifications are recorded and followed-up appropriately.

Table 1 shows the number of cases notified by condition over the previous 8-week period in South Australia.

Table 2 shows the number of cases notified by condition for this year and for the previous 3 years. Also shown for the previous 3 years is the number of cases notified up to the same date as this year.

Sexually transmitted diseases (STDs) are reported by medical practitioners and microbiological laboratories to the STD Clinic and data are available at Sexually Transmitted Diseases, South Australia.

Each case is entered in the week of the onset, or start, of the disease. At any time as more information comes to hand the numbers may change, either up or down.

The diseases are labelled according to the micro-organism that causes the specific disease. Organisms for which no notifications have been received do not appear in the table.

At this stage, some cases are confirmed with the disease, and some are suspected of having the disease. Those cases suspected of having disease are called presumptive. Presumptive cases are recorded with brackets, eg (1).

Medical practitioners and laboratories are an essential source of health information about infections in their communities. 

The considered opinions of medical practitioners on aetiology, time of onset, likely risk factors and the occurrence of similar cases, apparently related to the index case, are key epidemiological variables. The nature of the data available to the general practitioner differs from that derived from laboratories. Laboratories can provide reliable, timely information on the possible microbiological aetiology of a case and may, because of access to the cases from many medical practitioners, become aware of possible outbreaks not recognised by individual practitioners. 

In most instances, information from both sources is necessary to build up a picture of the dynamics of any particular agent of infection. This information, when combined with hospital separation statistics, death records, interstate and international health information, enables a surveillance authority, such as the Communicable Disease Control Branch (CDCB) to produce health intelligence that constitutes the basis for appropriate public health action.

The Public and Environmental Health Act, 1987, as amended, facilitates the collection of this information by:

• placing a duty upon doctors and laboratories to forward any relevant data on cases of Notifiable Diseases as designated in Schedules 1 and 2 of the Act to the South Australian Health Commission (SAHC). From 1 August 1996, notification by both clinicians and pathology laboratories became mandatory ‘on suspicion’ of a notifiable disease. Notification must be made as soon as possible and in any case within 3 days

• absolving the reporting doctor and laboratory from any legal liability concerning consent to release that information. Thus consent does not arise as an issue with regard to notifications made in good faith. It is wise, however, to inform a patient that the case will (or may) be notifiable and that they may be contacted during any further investigation

• preventing release by the SAHC of data that may identify individuals so collected to any person not involved in the follow-up of the case or cases. Others can only obtain notification data containing personal details by court order.

This is the general legal framework for the collection of notifiable disease data. However, the SAHC can determine the format of the report and the quantity and nature of the data required.

Detailed notes on the administrative features of notification of communicable diseases in South Australia are to be found in Notifiable Diseases Handbook including initial actions, definitions, follow-up and counselling.

The number of notifications received may be influenced by several factors that should be considered when interpreting the data. The proportion of all cases notified (case ascertainment or sensitivity) is unknown and may vary from disease to disease, from place to place and over time. There may be better case ascertainment for diseases for which laboratory confirmation is necessary. Conversely, diseases that can be only clinically diagnosed may be underestimated, or they may be overestimated if clinical case definitions are not highly specific for the disease. There may be better case ascertainment for rarer and more serious diseases than for common diseases without frequent serious complications.

Cases are normally notified some days after the onset of symptoms so the number of notifications received in reporting period will usually differ from the number of cases recorded as having dates of onset in that period. The undetermined sensitivities and specificities of the notification system mean that comparisons of notification rates reported for different diseases and for different reporting periods should be made with caution.

At any time the numbers may change either up or down.

Reporting form

Report of notifiable disease or related death form can be downloaded (Adobe PDF), completed and either posted or faxed to the Communicable Disease Control Branch. This form is not to be sent by email for reasons of confidentiality.