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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 December, 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'.

In December 2000, compared with the 5-year mean, reports of incident hepatitis C (ratio 1.3), chlamydial infection (1.2), Barmah Forest virus (1.1) and meningococcal infection (ratio 1.5) increased (Figure 1, Table 1).

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Gastrointestinal illness

Campylobacter notifications fell to 885 cases in December from 1299 cases in the previous month with a rate of 83.7/100,000 population but overall the trend in notifications is increasing. Salmonella notifications were lower than in the previous month with a rate of 32.1/100,000 population. Tasmania had the highest rate for Campylobacter (148/100,000 population) and the Northern Territory the highest for Salmonella (178/100,000 population).

Five cases of typhoid have been reported, four males in the 15 to 44 years age group and a 40-year-old female: four acquired the disease overseas, two from India, one from Indonesia (see Dr David Peacock's additional report, p32) and one from an unreported country. The New South Wales case had no history of overseas travel.

Shiga-toxin producing Escherichia coli was detected in South Australia in a 79-year-old male.

There were 4 cases of haemolytic uraemic syndrome in December, two male children aged 1 year and 2 years from Queensland and Western Australia respectively, and two females aged 58 years and 83 years both from New South Wales.

Chlamydial infection

There were 1056 notifications of chlamydial infection in December 2000, a notification rate of 66.1/100,000 population - an increase from previous years. Of these cases, 84 per cent were in the 15 to 34 years age range; the male:female ratio was 0.7:1. The Northern Territory continues to have the highest rate for chlamydial infection (337.7/100,000 population).

Vaccine preventable diseases

Apart from one report of tetanus, vaccine preventable disease reports for December were below those for the previous month and for the 5-year mean. The tetanus case, a 30-year-old male, was reported from New South Wales: his immunisation status was unknown.

Pertussis notifications were down compared with the previous month (397 cases with a rate of 24.9/100,000 population compared with 622 cases with a rate of 39/100,000 population). Since August 2000 (when the national rate for the year peaked at 46/100,000 population) the rates for all States except the Northern Territory have decreased. The rate for the Northern Territory increased from the previous month (18.7 per 100,000 population) to 24.9 per 100,000 population in December 2000.

Measles cases continue to be at their lowest level since the national notification system began. Five cases were reported in December 2000, all in New South Wales (see: Outbreak Report, p19). They included four partially vaccinated children (two boys aged 1 and 5 years and two girls aged 3 and 4 years) and a 31-year-old unimmunised male.

Of the Haemophilus influenza type b cases, three were children (a 1-year-old girl, and two boys aged 3 and 6 years) and one a 16-year-old female. The 16-year-old had not been immunised. The immunisation status of the 3-year-old was not stated and that of the other two cases unknown.

Legionellosis

There were 17 notifications of legionellosis in December 2000, a notification rate of 1.1/100,000 population. One case in Queensland was Legionella pneumophila and two in South Australia Legionella longbeachae. For the other cases information on the Legionella species involved was not available.

Meningococcal infections

There were 48 notifications of meningococcal infection in December 2000, a notification rate of 3.0/100,000 population. Of these cases, 40 per cent were under 5 years of age and 31 per cent were in the 5 to 19 years age group. The serogroups were available for 19 cases; these were serogroup B (68%) and serogroup C (32%).

Vectorborne diseases

In December there were fewer Barmah Forest virus infection notifications compared with November (51 cases with a rate of 3.2/100,000 population compared with 66 cases with a rate of 4.1/100,000 population) but these were slightly higher than the 5-year mean (48 cases). The majority (27 cases, 9.1/100,000 population) were from Queensland.

Ross River Virus notifications remain unchanged (159 cases with a rate of 10.0/100,000 population compared with November 2000, 164 cases with a rate of 10.3/100,000 population) the highest rate being in the Northern Territory (104.4/100,000 population). Most cases were reported from Queensland (62) and South Australia (51).


This article was published in Communicable Diseases Intelligence Volume 25, No 1, January 2001.