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National Influenza Surveillance, 1999

Three types of data are included in National Influenza Surveillance, 1999. These are sentinel general practitioner surveillance conducted by the Australian Sentinel Practice Research Network, Department of Human Services (Victoria), Department of Health (New South Wales) and the Tropical Influenza Surveillance Scheme, Territory Health (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. For further information about these schemes, see Commun Dis Intell 1999; 23:56.

Sentinel general practitioner surveillance

An increase in consultation rates for influenza-like illness reported by the ASPREN, NSW and Victorian schemes was apparent in April. Rates for influenza-like illness recorded by ASPREN were lower this year than for the same period in 1998. In contrast, the consultation rates for influenza activity reported by the Tropical Influenza Surveillance Scheme showed higher rates from March to June than for the same period in 1998. Victorian rates were similar to those recorded for the corresponding period in 1998.

Figure 4. Sentinel general practitioner influenza consultation rates, 1999, by scheme and week


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Laboratory surveillance

Figure 5 shows the number of laboratory reports for 1998 and 1999. Data for 1999 is provided only for January to July. For the year to date there have been 735 laboratory reports of influenza.

To July 1999, there have been 649 (88.3%) reports of influenza A of which 17 were H3N2 and 2 were H1N1 (Figure 6). There were 86 (11.7%) reports of influenza B. To date there has been no lodging of influenza reports in week 30.

Figure 5. Laboratory reports of influenza, 1998-99, by month of specimen collection



Figure 6. Laboratory reports of influenza, 1999, by type and by week of specimen collection

Absenteeism surveillance

Australia Post reports employees absent if they are not at work for three or more consecutive days in one week. The average rates for May were 0.45% which is higher than for May 1998 (0.28%) (Figure 7). There are no changes in the reports of absenteeism since the previous report.

Figure 7. Absenteeism rates in Australia Post, 1999



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Sentinel Chicken Surveillance Programme

Sentinel chicken flocks are used to monitor flavivirus activity in Australia. The main viruses of concern are Murray Valley encephalitis (MVE) and Kunjin which cause the potentially fatal disease Australian encephalitis in humans. Currently 26 flocks are maintained in the north of Western Australia, seven in the Northern Territory, nine in New South Wales and ten in Victoria. The flocks in Western Australia and the Northern Territory are tested year round but those in New South Wales and Victoria are tested only from November to March, during the main risk season.

Results are coordinated by the Arbovirus Laboratory in Perth and reported bimonthly. For more information see Commun Dis Intell 1999;23:57-58.

AK Broom,¹ JS Mackenzie,² L Melville,³ DW Smith⁴ and PI Whelan⁵

1. Department of Microbiology, The University of Western Australia
2. Department of Microbiology, The University of Queensland
3. Berrimah Agricultural Research Centre, Northern Territory
4. PathCentre, Western Australia
5. Department of Health and Community Services, Northern Territory

May/June 1999

Sentinel chicken serology was carried out for 24 of the 27 flocks in Western Australia in May and June 1999. There were again a large number of seroconversions to flaviviruses in the Kimberley, Pilbara and Gascoyne flocks during this period. Twenty-five of the total 34 seroconversions occurred in May 1999. The number of chickens positive for flavivirus antibodies by ELISA and the virus (or viruses) they were infected with is shown in Table 6.

Table 6. Flavivirus seroconversions in Western Australian sentinel chicken flocks in May and June, 1999

Location	May 1999			June 1999
	MVE	KUN	MVE/KUN	MVE
Kimberley
Kalumburu		1	1
Wyndham	1
Kununurra	1
Fitzroy Crossing	4
Lombadina	1	1
Derby*	2
Broome*	2
Pilbara
Port Hedland				1
Karratha		1		1
Harding Dam*				3
Tom Price	1
Paraburdoo	2			1
Newman*			1
Exmouth	3			3
Gascoyne
Carnarvon	3

* 2 flocks of 12 chickens at these sites
MVE Antibodies to Murray Valley encephalitis virus detected by ELISA
KUN Antibodies to Kunjin virus detected by ELISA
MVE/KUN Antibodies to both MVE and KUN viruses detected by ELISA
FLAVI Antibodies to a flavivirus only (not MVE or KUN) detected by ELISA

Serum samples from six of the seven Northern Territory sentinel chicken flocks were tested in our laboratory in May and June 1999. There were seroconversions to flaviviruses at Howard Springs and Leanyer (Darwin area) and from Beatrice Hill Farm and Tennant Creek. The number of chickens positive for flavivirus antibodies by ELISA and the virus (or viruses) they were infected with is shown in Table 7. Seroconversions to MVE virus from Tennant Creek in May have not yet been confirmed.

Table 7. Flavivirus seroconversions in the Northern Territory sentinel chicken flocks in May and June, 1999

Location	May 1999		June 1999
	MVE	KUN	MVE	KUN	MVE/KUN	FLAVI
Howard Springs	1
Leanyer		1		1	1	1
Beatrice Hill	3		2
Tennant Creek	2

MVE Antibodies to Murray Valley encephalitis virus detected by ELISA
KUN Antibodies to Kunjin virus detected by ELISA
MVE/KUN Antibodies to both MVE and KUN viruses detected by ELISA
FLAVI Antibodies to a flavivirus only (not MVE or KUN) detected by ELISA

Details of the locations of all chicken flocks are given in CDI 1999;23:57-58.

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HIV and AIDS Surveillance

National surveillance for HIV disease is coordinated by the National Centre in HIV Epidemiology and Clinical Research (NCHECR), in collaboration with State and Territory health authorities and the Commonwealth of Australia. Cases of HIV infection are notified to the National HIV Database on the first occasion of diagnosis in Australia, by either the diagnosing laboratory (ACT, New South Wales, Tasmania, Victoria) or by a combination of laboratory and doctor sources (Northern Territory, Queensland, South Australia, Western Australia). Cases of AIDS are notified through the State and Territory health authorities to the National AIDS Registry. Diagnoses of both HIV infection and AIDS are notified with the person's date of birth and name code, to minimise duplicate notifications while maintaining confidentiality.

Tabulations of diagnoses of HIV infection and AIDS are based on data available three months after the end of the reporting interval indicated, to allow for reporting delay and to incorporate newly available information. More detailed information on diagnoses of HIV infection and AIDS is published in the quarterly Australian HIV Surveillance Report, and annually in HIV/AIDS and related diseases in Australia Annual Surveillance Report. The reports are available from the National Centre in HIV Epidemiology and Clinical Research, 376 Victoria Street, Darlinghurst NSW 2010. Telephone: (02) 9332 4648; Facsimile: (02) 9332 1837; http://www.med.unsw.edu.au/nchecr.

HIV and AIDS diagnoses and deaths following AIDS reported for 1 to 31 March 1999, as reported to 30 June 1999, are included in this issue of Commun Dis Intell[(Tables 8 and 9).

Table 8. New diagnoses of HIV infection, new diagnoses of AIDS and deaths following AIDS occurring in the period 1 to 31 March 1999, by sex and State or Territory of diagnosis

		ACT	NSW	NT	Qld	SA	Tas	Vic	WA	Totals for Australia
										This period 1999	This period 1998	Year to date 1999	Year to date 1998
HIV diagnoses	Female	0	3	0	2	0	0	1	2	8	10	18	20
	Male	0	35	1	9	1	0	10	3	59	66	138	184
	Sex not reported	0	0	0	0	0	0	1	0	1	0	2	2
	Total1	0	38	1	11	1	0	12	5	68	76	158	206
AIDS diagnoses	Female	0	1	0	0	0	0	0	0	1	1	2	3
	Male	0	5	0	1	0	0	0	0	6	20	20	72
	Total1	0	6	0	1	0	0	0	0	7	21	22	75
AIDS deaths	Female	0	0	0	0	0	0	0	0	0	2	2	3
	Male	0	0	0	0	0	0	4	0	4	8	25	34
	Total1	0	0	0	0	0	0	4	0	4	10	26	37

1. Persons whose sex was reported as transgender are included in the totals.

Table 9. Cumulative diagnoses of HIV infection, AIDS and deaths following AIDS since the introduction of HIV antibody testing to 30 June 1999, by sex and State or Territory

		State or Territory								Australia
		ACT	NSW	NT	Qld	SA	Tas	Vic	WA
HIV diagnoses	Female	23	587	8	134	57	5	202	107	1,123
	Male	188	10,569	105	1,888	652	77	3,775	878	18,132
	Sex not reported	0	258	0	0	0	0	26	0	284
	Total1	211	11,433	113	2,029	709	82	4,016	988	19,581
AIDS diagnoses	Female	8	171	0	46	21	3	67	26	342
	Male	85	4,526	34	792	327	44	1,586	344	7,738
	Total1	93	4,709	34	840	348	47	1,660	372	8,103
AIDS deaths	Female	2	113	0	30	15	2	47	16	225
	Male	63	3,126	24	554	225	28	1,246	245	5,511
	Total1	65	3,247	24	586	240	30	1,299	262	5,753

1. Persons whose sex was reported as transgender are included in the totals.

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Childhood immunisation coverage

Tables 10 and 11 provide the latest quarterly report on childhood immunisation coverage from the Australian Childhood Immunisation Register (ACIR).

The data show the percentage of children fully immunised at age 12 months for the cohort born between 1 January and 31 March 1998 and at 24 months of age for the cohort born between 1 January and 31 March 1997, according to the Australian Standard Vaccination Schedule.

A full description of the methodology used can be found in Commun Dis Intell 1998;22:36-37.

Table 10. Percentage of children immunised at 1 year of age, preliminary results by disease and State for the birth cohort 1 January to 31 March 1998; assessment date 30 June 1999

Vaccine	State or Territory								Australia
	ACT	NSW	NT	Qld	SA	Tas	Vic	WA
Total number of children	1,070	21,453	982	12,233	4,697	1,541	14,848	6,195	63,019
Diphtheria, Tetanus, Pertussis (%)	89.5	85.3	79.7	89.4	89.7	88.3	89.1	87.4	87.6
Poliomyelitis (%)	89.3	85.0	79.1	88.8	89.6	88.3	89.3	87.2	87.3
Haemophilus influenzae type b (%)	89.2	84.7	84.9	89.7	89.1	88.0	88.8	87.1	87.4
Fully immunised (%)	88.7	83.5	77.3	88.0	88.6	87.7	87.9	85.9	86.1
Change in fully immunised since last quarter (%)	+1.0	+0.8	+2.7	+1.5	+1.1	+0.5	+1.4	+1.5	+1.2

Table 11. Proportion of children immunised at 2 years of age, preliminary results by disease and State for the birth cohort 1 January to 31 March 1997; assessment date 30 June 1999

Vaccine	State or Territory								Australia
	ACT	NSW	NT1	Qld	SA	Tas	Vic	WA
Total number of children	1051	22,006	946	11,888	4,628	1,558	15,454	6,475	64,006
Diphtheria, Tetanus, Pertussis (%)	86.2	81.3	67.7	85.5	83.2	83.6	83.6	82.0	82.8
Poliomyelitis (%)	88.9	85.6	79.9	91.0	88.4	89.5	89.3	85.3	87.7
Haemophilus influenzae type b (%)	85.4	81.3	77.2	85.8	81.3	83.3	83.6	82.2	82.8
Measles, Mumps, Rubella (%)	89.7	85.9	81.8	90.9	88.0	89.0	88.6	86.7	87.8
Fully immunised (%)2	81.4	70.4	57.8	80.3	71.6	74.8	74.7	70.5	73.5
Change in fully immunised since last quarter (%)	+3.7	+3.5	+3.2	+2.8	+3.5	+3.2	+2.7	+4.5	+3.2

1. The 12 months age data for this cohort was published in Commun Dis Intell 1998;22:233.
2. These data relating to 2 year old children should be considered as preliminary. The proportions shown as 'fully immunised' appear low when compared with the proportions for individual vaccines. This is at least partly due to poor identification of children on immunisation encounter forms.
Acknowledgement: These figures were provided by the Health Insurance Commission (HIC), to specifications provided by the Commonwealth Department of Health and Aged Care. For further information on these figures or data on the Australian Childhood Immunisation Register please contact the Immunisation Section of the HIC: Telephone 02 6124 6607.

This article was published in Communicable Diseases Intelligence Volume 23, No 8, 5 August 1999.