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Presentation of NNDSS data

In the March 2000 issue an additional summary table was introduced. Table 1 presents 'date of notification' data, which is a composite of three components: (i) the true onset date from a clinician, if available, (ii) the date the laboratory test was ordered, or (iii) the date reported to the public health unit. Table 2 presents the crude incidence of diseases by State or Territory for the current reporting month. Table 3 presents data by report date for information only. In Table 3 the report date is the date the public health unit received the report.

Table 1 now includes the following summary columns: total current month 2000 data; the totals for previous month 2000 and corresponding month 1999; a 5-year mean which is calculated using previous, corresponding and following month data for the previous 5 years (MMWR, 2000:49;139-146); year to date (YTD) figures; the mean for the year to date figures for the previous 5 years; and the ratio of the current month to the mean of the last 5 years.

Highlights for October, 2000

Communicable Disease Surveillance Highlights report on data from various sources, including the National Notifiable Diseases Surveillance System (NNDSS) and several disease specific surveillance systems that provide regular reports to Communicable Diseases Intelligence. These national data collections are complemented by intelligence provided by State and Territory communicable disease epidemiologists and/or data managers who have recently formed a Data Management Network. This additional information has enabled the reporting of more informative highlights each month.

The NNDSS is conducted under the auspices of the Communicable Diseases Network Australia New Zealand, and the CDI Virology and Serology Laboratory Reporting Scheme (LabVISE) is a sentinel surveillance scheme. In this report, data from the NNDSS are referred to as 'notifications' or 'cases', whereas those from ASPREN are referred to as 'consultations' or 'encounters' while data from the LabVISE scheme are referred to as 'laboratory reports'.

Three types of data are included in National Influenza Surveillance, 2000. These are sentinel general practitioner surveillance conducted by the Australian Sentinel Practice Research Network (ASPREN), the Department of Human Services (Victoria), the Department of Health (New South Wales) and the Tropical Influenza Surveillance Scheme, Territory Health Services (Northern Territory); laboratory surveillance data from the Communicable Diseases Intelligence Virology and Serology Laboratory Reporting Scheme (LabVISE) and the World Health Organization Collaborating Centre for Influenza Reference and Research; and absenteeism surveillance conducted by Australia Post. Data from ASPREN are referred to as 'consultations' or 'encounters'. For further information about these schemes, see Commun Dis Intell 2000;24:9-10.

In October 2000 the number of reports of chlamydial infection (Ratio 1.6), legionellosis (Ratio 1.4) and meningococcal infection (Ratio 1.4) has increased compared with the 5-year mean (Figure 7, Table 1).

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Gastrointestinal illness

Campylobacter and Salmonella notifications continue to be fewer than in previous years with a rate of 118/100,000 population for Campylobacter and 24.1/100,000 population for Salmonella (Figure 1). The Australian Capital Territory had the highest rate for Campylobacter (237/100,000 population) and the Northern Territory the highest rate for Salmonella (112/100,000 population)

An outbreak of ten (4 male, 6 female) cases of Salmonella Typhimurium phage type 44 infection linked to a restaurant in metropolitan Adelaide was investigated by local government Environmental Health Officers and the Communicable Disease Personnel in South Australia. Cases report eating at the restaurant from the 4 to 7 October 2000. A case-control study is currently being conducted. Also an apparent cluster of cases of Campylobacter infection in residents of a small rural community in South Australia is being investigated. Hypothesis generating interviews are being conducted with cases to identify the source of the cluster. Two cases have reported the consumption of raw milk and raw milk products from local dairies.

Figure 1. Notification rate of salmonellosis, Australia, 1 January 1991 to 31 October 2000, by month of notification



There was one case of typhoid reported in New South Wales in a 33-year-old male.

There were two notifications of Shiga-like Escherichia coli (SLTEC)/verotoxigenic Escherichia coli (VTEC) in October 2000 from South Australia, both were in males one aged 33 years and one aged 66 years.

There was a small outbreak in a student residential setting in Tasmania with 3 confirmed cases of Campylobacter. Nine other residents had the same symptoms but were not tested. The total population was 150 persons. Several deficiencies in food handling practices but no common food items were identified. No further cases have been reported.

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Chlamydial infection

There were 1,327 notifications of chlamydial infection in October 2000 - a notification rate of 84.0/100,000 population which is an increased rate from previous months (Figure 2). Of these cases, 78 per cent were in the 15 to 29 age groups. The Northern Territory continues to have the highest rate for chlamydial infection (385.7/100,000 population).

Figure 2. Notification rate of chlamydial infection, Australia, 1 January 1991 to 31 October 2000, by month of notification



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Vaccine preventable diseases

All vaccine preventable diseases had fewer reports this month than for the 5-year-mean for October. Pertussis notifications are down from last month (396 cases with a rate of 25.1/100,000 population compared with 624 cases with a rate of 39.5/100,000 population) (Figure 3).

Measles cases continue to be at their lowest level since the national notification system began (Figure 4). Of the ten cases reported in October 2000, four were reported in New South Wales, three in Queensland, two in Victoria and one in South Australia.

The New South Wales cases were part of two measles clusters which have recently occurred in that State. The first cluster of 10 cases began with an imported case of measles in late August, which resulted in four generations of cases affecting mostly young unimmunised adults. The second cluster of five cases has occurred in unimmunised or incompletely immunised children, with confirmed links between four of the cases. The cases in Queensland, Victoria and South Australia included a 32-year-old male (unknown vaccination status who acquired the infection interstate at the Olympics), an 8-year-old female with two documented vaccinations (who acquired the infection locally), a 27-year-old female vaccinated once only (who acquired the infection locally), a one-year-old male, a 21-year-old female and a one-year-old female.

Figure 3. Notification rate of pertussis, Australia, New South Wales and Australian Capital Territory, 1 January 1999 to 31 October 2000, by month of notification



Figure 4. Notification rate of measles, Australia, 1 January 1991 to 31 October 2000, by month of notification



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Legionellosis

There were 22 notifications of legionellosis in October 2000 - a notification rate of 1.4/100,000 population (Figure 5) with South Australia having the highest rate for legionellosis (7.2/100,000 population).

Figure 5. Notification rate of legionellosis, Australia, 1 January 1991 to 31 October 2000, by month of notification



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Meningococcal infections

There were 63 notifications of meningococcal infection in October 2000 - a notification rate of 4.0/100,000 population (Figure 6). Of these cases, 33 per cent were under 5 years of age and 38 per cent were in the 15 to 24 year age group. The serogroups were available for 22 cases; these were serogroup B (45%), serogroup C (50%) and serogroup W135 (5%).

Figure 6. Notification rate of meningococcal infection, Australia, 1 January 1991 to 31 October 2000, by month of notification




This article was published in Communicable Diseases Intelligence Volume 24, No 11, November 2000.