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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'.

Vaccine preventable diseases

Notifications of Measles and Rubella continue to be low in both the NNDSS and LabVISE reporting scheme.

The number of pertussis notifications, when examined by date of onset, has fallen in each month from November 1997 to August 1998. A plateau appears to have been reached with the number of notifications having onset in September 1998 being 354 compared with 330 for August 1998. A small fall is seen again for October but this is probably because not all notifications for that month have yet been received by the NNDSS (Figure 1). Historical data commonly shows a rise in notifications in the later months of the year.

Figure 1. Notifications of pertussis, Australia, 1992 to 1998, by month of onset

Arboviruses

The number of notifications for dengue remains high with 35 more reports in this period (30 from Queensland). The total for 1998 to date is more than double that for the same period in 1997.

Respiratory viruses

Reports of Parainfluenza type 1 have declined in recent months after peaking in April. Epidemics of Parainfluenza virus type 1 occur in Australia in the autumn-winter months of alternate years. The number of reports received so far this year is similar to that for the same period in 1996 but lower than the last epidemic year of 1994 (Figure 2). In previous epidemic years reports have peaked in April and May.

Parainfluenza virus type 2 reports have declined over recent months. Reporting this year has been lower than that for previous years.

Reports of Parainfluenza virus type 3 have declined over the past months after peaking in August this year. Parainfluenza Type 3 virus has maintained its seasonal pattern although the total number of reports this year has been lower than for previous years. Parainfluenza virus type 3 is most commonly reported in the first 12 months of life. Bronchiolitis and pneumonia are the most common clinical symptoms.

Figure 2. Laboratory reports of Parainfluenza virus type 1,2 and 3, 1994 to 1998, by month of specimen collection




This article was published in Communicable Diseases Intelligence Volume 22, No 12, 26 November 1998.