Communicable Diseases Surveillance - Additional reports

This report published in Communicable Diseases Intelligence Volume 26, No 2, June 2002 contains an analysis and tables of monthly notifiable diseases and laboratory data, and quarterly surveillance reports.

Page last updated: 12 July 2002

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




Rotavirus Surveillance

The National Rotavirus Reference Centre (NRRC) undertakes surveillance and characterisation of rotavirus strains causing annual epidemics of severe diarrhoea in young children throughout Australia. Reduction in funding after June 2001 has limited the national scope of surveillance. Priority has been given to comprehensive surveillance of strains infecting children admitted to hospital in Western Australia, the Northern Territory and Victoria. Previous experience has shown Western Australia and Northern Territory to show differing epidemiological patterns from those of the eastern states and to be sites where 'new' strains have appeared. Melbourne's epidemiological patterns in the past have been similar to those in Brisbane, Adelaide and Hobart, and is currently regarded as representative of those locations.

The NRRC retains an interest in providing a service available to all sites if unusual epidemic patterns are observed and can be contacted at the Murdoch Childrens Research Institute, Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Flemington Road, Parkville, Victoria, 3052. Contact: Ruth Clark, Telephone: +61 3 9345 5069. Facsimile: +61 3 9345 6240. E-mail: clarkr@cryptic.rch.unimelb.edu.au. For more information see Commun Dis Intell 2000;24:10.

The National Rotavirus Reference Centre (NRRC) conducted rotavirus surveillance Australia-wide in 2001. One thousand and eighteen samples were collected from children admitted to hospital with acute gastroenteritis, of which 865 were confirmed as rotavirus positive. Serotype analysis of these samples was conducted using a combination of enzyme immunoassays, PCR and Northern hybridisation. This analysis revealed that serotype G1 was the major serotype, representing 42.4 per cent of all strains, followed by serotype G9 (36.5% of all strains). All other serotypes represented less than 2.5 per cent of strains (Table 7). However, there was variation in the prevalence rates in several of the participating centres, with serotype G1 being the dominant strain in Melbourne and Perth, whereas serotype G9 was the dominant strain in Alice Springs, Darwin and Mt Isa.

There was an increase in the prevalence of serotype G4 in Melbourne during 2001. Whether the Melbourne serotype G4 strains identified in 2001 are related to the earlier serotype G4 strains prevalent in Darwin and Sydney during 2000, requires further analysis.

A major outbreak in the Northern Territory started in May 2001, and persisted through the year.1 Serotype G9 was the dominant strain. This 'new' serotype has been reported world-wide since 1998 and its incorporation in candidate rotavirus vaccines is under discussion. It is important to keep track of changing strains, so that Australia is well placed to implement an appropriate vaccine when one reaches licensure.

Rotavirus collection continues and the National Rotavirus Reference Centre welcomes any notifications of rotavirus outbreaks.

Table 7. Rotavirus G types, January to December, 2001

Centre
G serotype (% of rotavirus positive) Rotavirus positive samples
G1 G2 G3 G4 G9 NR* mix
Melbourne
85
(48.3)
8
(4.6)
0
12
(6.8)
18
(10.2)
50
(28.4)
3
(1.7)
176
Perth
201
(65.7)
1
(0.33)
1
(0.33)
0
57
(18.6)
42
(13.7)
4
(1.3)
306
WA Pathcentre
35
(34.3)
1
(1)
0
1
(1)
46
(45.1)
14
(13.7)
5
(4.9)
102
Darwin
1
(3.3)
0
0
0
28
(93.3)
1
(3.3)
0
30
Darwin W. Path
3
(6.8)
0
0
1
(2.3)
32
(72.7)
8
(18.2)
0
44
Alice Springs
40
(24.9)
0
0
0
111
(68.9)
10
(6.2)
0
161
Mt Isa
0
0
0
0
23
(92)
2
(8)
0
25
Adelaide
1
(50)
0
0
0
0
1
(50)
0
2
Brisbane
1
(25)
2
(50)
0
0
0
1
(25)
0
4
Hobart
0
6
(46.2)
0
0
0
7
(53.8)
0
13
West Sydney
0
1
(50)
0
0
1
(50)
0
0
2
Total
367
(42.4)
19
(2.2)
1
(0.1)
14
(1.6)
316
(36.5)
136
(15.7)
12
(1.4)
865

* NR - unable to be serotyped with monoclonal antibodies.
1018 specimens were forwarded to the NRRC, 865 were confirmed as positive


Reference

1. Armstrong P. NT Disease Control Bulletin 2001;8:1-5.

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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 (Australian Capital Territory, 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, Viral Hepatitis and Sexually Transmissible infections 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. Internet: http://www.med.unsw.edu.au/nchecr. Telephone: +61 2 9332 4648. Facsimile: +61 2 9332 1837. For more information see Commun Dis Intell 2002;26:59.

HIV and AIDS diagnoses and deaths following AIDS reported for 1 October to 31 December 2001, as reported to 31 March 2002, are included in this issue of Communicable Diseases Intelligence (Tables 8 and 9).

Table 8. New diagnoses of HIV infection, new diagnoses of AIDS and deaths following AIDS occurring in the period 1 October to 31 December 2001, by sex and State or Territory of diagnosis

 
Sex
State or Territory Totals for Australia
ACT NSW NT Qld SA Tas Vic WA This period 2001 This period 2000 Year to date 2001 Year to date 2000
HIV diagnoses Female
1
7
0
5
3
0
7
2
25
14
94
78
Male
1
76
1
25
12
0
54
5
174
140
680
664
Not reported
0
0
0
0
0
0
0
0
0
1
2
1
Total1
2
83
1
30
15
0
61
7
199
156
777
746
AIDS diagnoses Female
0
0
0
0
2
0
2
0
4
2
16
22
Male
0
14
0
5
2
0
6
1
28
56
127
214
Total1
0
14
0
5
4
0
8
1
32
58
144
236
AIDS deaths Female
0
0
0
0
0
0
3
0
3
1
11
8
Male
0
11
0
1
1
0
3
0
16
29
70
123
Total1
0
11
0
1
1
0
6
0
19
30
81
131

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 31 March 2002, by sex and State or Territory

 
Sex
State or Territory Australia
ACT NSW NT Qld SA Tas Vic WA
HIV diagnoses Female 28 672 10 180 72 5 250 132 1,349
Male 231 11,562 112 2,153 727 80 4,203 981 20,049
Not reported 0 244 0 0 0 0 24 0 268
Total1 259 12,500 122 2,340 799 85 4,493 1,119 21,717
AIDS diagnoses Female 9 208 0 51 28 3 79 27 405
Male 88 4,823 37 883 363 45 1,725 364 8,328
Total1 97 5,043 37 936 391 48 1,813 393 8,758
AIDS deaths Female 4 118 0 35 16 2 57 18 250
Male 70 3,281 25 588 242 29 1,313 260 5,808
Total1 74 3,407 25 625 258 31 1,377 279 6,076

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 October to 31 December 2000 and at 24 months of age for the cohort born between 1 October to 31 December 1999 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.

Commentary on the trends in ACIR data is provided by the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases (NCIRS). For further information please contact NCIRS at: telephone +61 2 9845 1256, E-mail: brynleyh@chw.edu.au.

The percentage of Australian children 'fully immunised' by 12 months increased marginally from the last quarter by 0.1 percentage points to 90.5 per cent (Table 10). The change in the percentage 'fully immunised' varied by State and Territory. New South Wales (+0.7%), the Australian Capital Territory (+0.5%), the Northern Territory (+2.4%), and South Australia (+0.1%) showed an increase in coverage. Queensland, Western Australia, Tasmania and Victoria experienced no change or a marginal decrease in coverage in the quarter. Coverage is now below 90 per cent in only two jurisdictions, the Northern Territory (89.7%) and Western Australia (88%). Immunisation coverage for DTP and OPV by 12 months in Australia decreased marginally from the previous quarter whilst coverage for Hib and hepatitis B increased marginally. The biggest improvement in coverage by 12 months was seen in the Northern Territory, where coverage for DTP increased by 1.9 per cent, OPV by 1.4 per cent, Hib by 3 per cent and hepatitis B by 3.2 per cent.

Coverage measured by the percentage of Australian children 'fully immunised' at 24 months decreased marginally from the last quarter by 0.2 percentage points to 87.8 per cent (Table 11). Coverage increased compared with the previous quarter in three states and territories, the Northern Territory (2.4%), New South Wales (0.5%) and Western Australia (0.8%). Queensland, South Australia, Tasmania and Victoria experienced no change or a small decrease in coverage with South Australia experiencing the largest decrease (2.4%). Coverage for individual vaccines by 24 months for Australia however, is much greater than for 'fully immunised', with coverage for Hib greater than 95 per cent and coverage for OPV and MMR approaching 95 per cent.

Figure 6 shows the trends in vaccination coverage from the first ACIR-derived published coverage estimates in 1997 to the current estimates. There is a clear trend of increasing vaccination coverage over time for children aged 12 months and 24 months. However, the rate of increase in coverage is slowing with the curve beginning to flatten out for estimates at 12 months of age.

Figure 6. Trends in vaccination coverage, Australia, 1997 to 2001, by age cohorts

Figure 6. Trends in vaccination coverage, Australia, 1997 to 2001, by age cohorts

Table 10. Percentage of children immunised at 1 year of age, preliminary results by disease and State for the birth cohort 1 October to 31 December 2000; assessment date 31 March 2002

Vaccine
State or Territory Australia
ACT NSW NT Qld SA Tas Vic WA
Number of children
1,084
21,340
845
12,019
4,231
1,535
15,258
5,848
62,160
Diphtheria, Tetanus, Pertussis (%)
92.9
91.9
90.7
92.0
92.2
92.1
92.8
90.1
92.0
Poliomyelitis (%)
92.8
91.8
90.5
91.9
92.0
92.1
92.8
90.0
91.9
Haemophilus influenzae type b (%)
94.7
94.5
96.1
94.3
94.5
95.7
95.0
93.1
94.5
Hepatitis B (%)
95.0
94.7
96.3
94.8
94.9
94.9
94.1
92.2
94.4
Fully immunised (%)
91.4
90.6
89.7
90.8
90.6
91.0
91.0
88.0
90.5
Change in fully immunised since last quarter (%)
-0.5
+0.7
+2.5
-0.7
+0.1
-0.3
+0.0
-1.1
+0.1


Table 11. Proportion of children immunised at 2 years of age, preliminary results by disease and State for the birth cohort 1 October to 31 December 1999; assessment date 31 March 20021

Vaccine
State or Territory Australia
ACT NSW NT Qld SA Tas Vic WA
Number of children
999
20,711
759
11,714
4,417
1,483
15,149
6,132
61,364
Diphtheria, Tetanus, Pertussis(%)
89.9
89.7
86.8
91.1
90.0
90.4
90.9
89.1
90.2
Poliomyelitis (%)
95.0
94.1
94.6
94.0
94.6
96.1
95.2
93.8
94.4
Haemophilus influenzae type b(%)
95.8
95.4
94.1
95.0
95.4
96.6
96.1
94.7
95.4
Measles, Mumps, Rubella(%)
94.4
92.8
94.2
93.2
93.2
95.1
94.1
92.9
93.4
Fully immunised(%)2
88.5
86.9
85.9
88.8
87.5
89.6
88.8
86.3
87.8
Change in fully immunised since last quarter(%)
-1.6
+0.5
+2.4
-1.4
-2.4
-0.5
-0.0
+0.8
-0.2

1. The 12 months age data for this cohort were published in Commun Dis Intell 2001;25:94.
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.
Acknowledgment: These figures were provided by the Health Insurance Commission (HIC), to specifications provided by the Commonwealth Department of Health and Ageing. For further information on these figures or data on the Australian Childhood Immunisation Register please contact the Immunisation Section of the HIC: Telephone: +61 2 6124 6607.


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National Enteric Pathogens Surveillance System

The National Enteric Pathogens Surveillance System (NEPSS) collects, analyses and disseminates data on human enteric bacterial infections diagnosed in Australia. These pathogens include Salmonella, E. coli, Vibrio, Yersinia, Plesiomonas, Aeromonas and Campylobacter. Communicable Diseases Intelligence reports only on Salmonella.

Data are based on reports to NEPSS from Australian laboratories of laboratory-confirmed human infection with Salmonella. Salmonella are identified to the level of serovar and, if applicable, phage-type. Infections apparently acquired overseas are included. Multiple isolations of a single Salmonella serovar/phage-type from one or more body sites during the same episode of illness are counted once only. The date of the case is the date the primary diagnostic laboratory isolated a Salmonella from the clinical sample.

Note that the historical quarterly mean count should be interpreted cautiously, and is affected by surveillance artefacts such as newly designated and incompletely typed Salmonella.

We thank contributing laboratories and scientists. Joan Powling (NEPSS Coordinator) and Mark Veitch (Public Health Physician), Microbiological Diagnostic Unit - Public Health Laboratory, Department of Microbiology and Immunology, University of Melbourne. For further information please contact NEPSS at the above address or on Telephone: +61 3 8344 5701, Facsimile: +61 3 8344 7833.

Reports to the National Enteric Pathogens Surveillance System of Salmonella infection for 1 January to 31 March 2002 are shown in Tables 12 and 13. Data includes cases reported and entered by 15 April 2002. Counts are preliminary, and subject to adjustment after completion of typing and reporting of further cases to NEPSS.

Table 12. Reports to the National Enteric Pathogens Surveillance System of Salmonella isolated from humans during the period 1 January to 31 March 2002, as reported to 15 April 2002

  Australia ACT NSW NT Qld SA Tas Vic WA
Total all Salmonella for quarter
2,585
39
708
101
965
117
55
423
177
Total contributing Salmonella types
225
20
106
43
119
43
15
100
62


Table 13. Top 25 Salmonella types identified in Australian States and Territories, 1 January to 31 March 2002

National rank
Salmonella type
Total 1st quarter 2002 Last 10 years mean 1st quarter Year to date 2002 Year to date 2001 Total 2001 ACT NSW NT Qld SA Tas Vic WA
1 S. Typhimurium 9
279
148
279
160
398
14
165
0
31
8
3
42
16
2 S. Typhimurium 135
262
176
262
276
638
1
83
2
49
6
8
71
42
3 S. Saintpaul
145
117
145
98
288
0
10
1
108
2
1
14
9
4 S. Virchow 8
137
48
137
82
245
0
10
0
119
0
0
8
0
5 S. Typhimurium 170
132
31
132
19
148
0
59
0
24
0
0
48
1
6 S. Birkenhead
109
84
109
99
248
0
45
2
58
0
0
4
0
7 S. Aberdeen
67
32
67
33
87
0
4
0
54
0
0
9
0
8 S. Hvittingfoss
59
17
59
25
89
1
5
3
46
2
0
1
1
9 S. Typhimurium 126
58
26
58
58
314
0
13
1
11
11
1
21
0
10 S. Chester
48
58
48
67
166
1
9
6
25
2
0
2
3
11 S. Waycross
48
37
48
19
53
0
16
1
31
0
0
0
0
12 S. Muenchen
43
57
43
52
125
0
2
5
28
2
0
1
5
13 S. Virchow 34
41
28
41
32
87
1
17
0
16
0
1
6
0
14 S. Infantis
37
47
37
44
123
3
12
0
9
3
0
6
4
15 S. Mississippi
35
31
35
67
124
0
1
0
0
0
32
2
0
16 S. Anatum
32
32
32
20
58
0
3
5
19
0
0
1
4
17 S. Typhimurium 4
31
16
31
62
141
2
6
0
6
5
0
12
0
18 S. Montevideo
30
5
30
6
27
1
22
2
4
0
0
1
0
19 S. Mgulani
29
12
29
12
66
0
1
0
27
0
0
1
0
20 S. Potsdam
28
20
28
22
60
0
14
0
13
0
0
0
1
21 S. Typhimurium RDNC
22
43
22
30
102
0
11
0
2
1
0
8
0
22 S. Typhimurium U290
22
1
22
4
27
1
14
0
0
0
1
4
2
23 S. Agona
21
17
21
13
56
1
7
1
1
7
0
2
2
24 S. Typhimurium 12
21
6
21
18
62
0
6
1
6
7
0
1
0
25 S. Singapore
19
19
19
14
64
0
10
0
4
3
0
1
1
Total of 25 most common types
1,755
 
 
 
 
26
545
30
691
59
47
266
91



This article was published in Communicable Diseases Intelligence Volume 26, No 2, June 2002

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