A print friendly PDF version is available from this Communicable Diseases Intelligence issue's table of contents.

Presentation of NNDSS data

In the March 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 data by report date for information only. In Table 2 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 Weekly February 25, 2000:49(07);139-146); year to date 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

Communicable Diseases Surveillance consists of data from various sources. The National Notifiable Diseases Surveillance System (NNDSS) is conducted under the auspices of the Communicable Diseases Network Australia New Zealand. The Virology and Serology Laboratory Reporting Scheme (LabVISE) is a sentinel surveillance scheme. The Australian Sentinel Practice Research Network (ASPREN) is a general practitioner-based 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'.

Bloodborne diseases

There were 1,666 notifications of hepatitis C reported in March 2000 that were not already on the State and Territory notifiable disease systems. This was a decrease from February 2000 (2,169), and March last year (1,952) but an increase from the mean of the last 5 years (1,324). Of these, 20 were identified to be incident cases. The majority of the incident notifications were in the 15-34 year old age group (95%) and the male to female ratio was 1:3.

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Gastrointestinal diseases

There were 672 notifications of salmonellosis in March 2000. This was an increase from February 2000 (639), but a decrease from March last year (1,309) and the mean of the last 5 years (798) (Figure 1). Thirty-seven per cent (250 cases) were in the 0-5 year age group with an overall male to female ratio of 1:1.

There were 7 notifications of typhoid in March 2000. Of the 4 States reporting SLTEC/VTEC there were 4 cases, all from South Australia. There were also 2 cases of HUS in Victoria; both in the 0-4 year age group.

Figure 1. Notifications of salmonellosis, January 1991 to March 2000, by date of notification



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Quarantinable diseases

There were no cases of cholera, plague, rabies, yellow fever or viral haemorrhagic fever in March 2000.

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Sexually transmissible diseases

There were 1,889 notifications of sexually transmissible diseases in March 2000, which is similar to February 2000 (1,857) and March last year (1,982) but is greater than the mean for the last 5 years (1,393). The increase in notifications of sexually transmitted diseases again is mainly due to the increased notifications for chlamydial infection (ratio 1.5) and gonococcal infection (ratio 1.2).

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Vectorborne diseases

There were 25 notifications of dengue in March 2000, which was a decrease from February 2000 (59), but an increase from March last year (14) and the mean for the last 5 years (18). The notifications were in all age groups with a male to female ratio of 1:1. The cases were mainly reported from Queensland (12) and Northern Territory (9) (Figure 2).

Figure 2. Notifications of dengue, January 1999 to March 2000, Northern Territory, Queensland and Australia, by date of notification



There were 602 notifications of Ross River virus infection in March 2000, which was a decrease from February 2000 (624), from March last year (1,000) and the mean for the last 5 years (990). The majority of notifications were in Queensland (37%) and Western Australia (23%), and in the 25-49 year age group (63%) with a male to female ratio of 0.9:1.

There were 83 notifications of malaria in March 2000, which was a decrease from February 2000 (90) but an increase from March last year (64) and from the mean for the last 5 years (73) (Figure 3). The cases were due to the following species of Plasmodium: 57 P. vivax, 14 P. falciparum, 2 P. ovale, 1 P. malariae and 1 P. falciparum/P. vivax. Most notifications were from Queensland (52) and all cases were imported. The majority of notifications were in the 15-29 year age group (61%) with a male to female ratio of 3.8:1.

Figure 3. Notifications of malaria, January 1999 to March 2000, Northern Territory, Queensland, New South Wales and Australia, by date of notification



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Vaccine preventable diseases

The total number of notifications for the different VPDs reached the lowest level since 1993 (Figure 4), with 213 notifications in March 2000. This was mainly the result of a continuing decline in notifications of pertussis.

Figure 4. Notification trends of vaccine preventable diseases, January 1993 to March 2000



There were no notifications of diphtheria or poliomyelitis. There was one case of Haemophilus influenzae type b reported from Queensland in a girl under 5 years of age with an unknown immunisation status. One case of tetanus was reported from New South Wales in a 76 year old female who was partly immunised. There was a slight increase in notifications of mumps in this notification period (16), compared with February 2000 (15), March 1999 (12) and the mean of the last five years (13). Most mumps cases occurred in the 20-24 year age group (44%), and the cases were evenly distributed between gender.

There were 9 cases of measles in March 2000, a decrease from February 2000 (12), March 1999 (75) and the mean of the last five years (51). Two cases were in the under 5 year age group (22%). The overall male to female ratio was 2:1. The immunisation status was unavailable for all the cases. Similarly, there was a decrease in rubella notifications in March 2000 (8), compared with February 2000 (17), March 1999 (29) and the mean of the last five years (109). Most rubella cases were evenly distributed between decade age groupings up to 44 years of age with a male to female ratio 1.7:1.

A total of 178 pertussis notifications were received with a notification date in March 2000. This was the lowest number since June 1993. Most pertussis cases occurred in the 10-14 year age group (44/178; 25%), with an overall male to female ratio 0.8:1 (Figure 5). Immunisation status was only provided for 20 pertussis notifications with 5 cases fully immunised, 11 partly immunised and 4 not immunised.

Figure 5. Notifications of pertussis, March 2000, by age group and sex



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Other bacterial diseases

There were 25 notifications of legionellosis in March 2000, with the majority again being in Victoria (60%) (please note Victorian outbreak report for April on page 92). This was less than for February 2000 (29) and for March last year (32) but was more than for the mean for the last 5 years (20).

There were 23 notifications of meningococcal infection in March 2000, with the majority again being in New South Wales (43%) and Victoria (35%). This was similar to that for February 2000 (22) and for the mean of the last 5 years (23), but less than for March last year (33). The majority of cases were either in the under 5 year age group (30%) or the 15-24 year age group (39%) (Figure 6). The overall male to female ratio was 1:1. Serotype information was provided for 48% (11/23) of the cases, with 45% serotype B (n=5) and 55% serotype C (n=6).

Figure 6. Notifications of meningococcal infection, January to March 2000, by age group and sex



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Echovirus 30 reports 1990-2000

The Virology and Serology Laboratory Reporting Scheme (LabVISE) is a voluntary scheme that receives reports from sentinel laboratories around Australia. LabVISE received 529 reports of echovirus 30 between January 1990 and January 2000. Victoria and New South Wales reported most activity (Figure 7). Victoria recorded a peak in the summer of 1994 and an increase in activity in December 1999, which continued into January 2000. New South Wales reported summer peaks in both 1994 and 1995 and a smaller winter peak in 1998. The majority of reports (51%) were received in late spring and summer. Other States reported a low level of activity over this period.

Figure 7. LabVISE reports of echovirus 30, Victoria and New South Wales, 1990-2000



The age distribution of cases from whom echovirus 30 was isolated is shown in Figure 8. Over the 10 year period, 29% of reports were from children aged 0-9 years and 25% were in the 30-39 years age group. The male to female ratio was 1.04:1.

Figure 8. LabVISE echovirus 30 reports by age group and sex, 1990-2000



A clinical diagnosis was recorded for 73% (n=387) of reports. Of these, the most common clinical diagnosis was meningitis (87%).

The most common site of isolation of echovirus 30 was cerebrospinal fluid (64%) followed by respiratory tract (17%) and faeces (14%). All echovirus 30 isolates were diagnosed by viral culture techniques and confirmed by neutralisation or molecular techniques.


This article was published in Communicable Diseases Intelligence Volume 24, No 4, April 2000.