Northern Territory
Sexual Health and Blood Borne Viruses Unit Surveillance Update
Department of Health and Community Services, Vol. 6 No 2, July-September 2005 & October-December 2005
A. Introduction:
This surveillance update presents quarterly statistics of all notifiable sexually transmissible infections (STIs) and blood borne viruses (BBVs) in the Northern Territory (NT) for the last two quarters of 2005. Where possible, annual statistics for 2005 are also provided.
The aim of the report is to provide quarterly statistics of notifiable STIs and BBVs at district and Territory level. Comparisons of notification rates with other jurisdictions and/or Australia as a whole are also provided where appropriate.
The report is divided into sections on notifiable sexually transmissible bacterial infections (gonorrhoea, chlamydia, syphilis and trichomoniasis) and blood borne viruses (hepatitis C and human immunodeficiency virus). Donovanosis is presented separately due to its small numbers of notifications.
All data used for this report have been extracted from the Northern Territory Notifiable Diseases Surveillance System (NTNDSS), and the HIV and AIDS Database maintained by the Sexual Health and Blood Borne Viruses Unit (SHBBVU). Statistics for other jurisdictions and Australia were from ‘HIV/AIDS, viral hepatitis and sexually transmissible infections in Australia Annual Report 2005’ published by National Centre in HIV Epidemiology and Clinical Research.
B. Quarterly Statistics of STI/BBV Notifications:
The following descriptions and comments refer specifically to the numbers and rates1 of notifications for the last two quarters of 2005 unless stated otherwise.
1 The rates reported in this section are crude rates. Except for annual rates, all rates in this section are annualised rates. The denominators for the rates of a quarters and a half-year are a quarter and a half of the NT population for that year respectively.
B.1 Gonorrhoea
During this reporting period, 747 notifications of gonorrhoea were recorded in the NT, which gave an annualised rate of 736.9 cases per 100,000 people, compared with 752.3 per 100,000 in the same period last year and 985.5 per 100,000 in the first half of 2005 (Table 1.1). The notification rate for 2005 of 861.2 per 100,000 represents an 8.8% increase over the 2004 rate of 791.8 per 100,000 (Fig. 1.1), and is consistent with a general increasing trend noted in the last decade.
There were slightly more female cases than male ones (52.3% vs. 47.7%), but the rates were similar (Table 1.2). The vast majority (83.9%) of all notifications were Aboriginal and the Aboriginal rate was over 18 times the non-Aboriginal rate (Table 1.3). However, both rates were substantially higher than the national rate (35.8 per 100,000 in 2004). It is worth noting that, compared with the rate for the same period in 2004, the Aboriginal rate remained extremely high at around 2000 per 100,000, while there was a 20% increase in the non- Aboriginal rate (from 97.9 per 100,000 to 117.2 per 100,000).
Alice Springs continued to record the highest number and rate of notifications (Table 1.4 and Fig. 1.4). 47.9% of all cases were notified in Alice Springs District. The rate for Darwin of 348.7 per 100,000 was the lowest among all districts, but it represented 28.9% of all notifications. Compared with the national rate of 37.0 per 100,000, even the rate for Darwin was significantly higher (about 9.4 times).
The numbers of cases and rates continued to be highest in the 15 to 24 year age groups, consistent with the observed pattern for the NT and Australia in recent years. These age groups contributed about half of all notifications during this reporting period (Table 1.5).
While the notification rates for the rural area of the two largest districts in the NT, i.e. Darwin and Alice Springs, were considerably higher than those of their urban counterparts, the numbers of notifications were higher in the urban areas (Table 2.1 and Fig. 2.1). Compared with the first half of 2005, only the number and rate of notifications for Alice Springs Rural area showed a significant change (decreased from 399 cases to 155). The main reason for this difference may be because there was a large-scale annual STI screening conducted in Alice Springs Rural communities in April.
B.2 Genital Chlamydia
There were 732 cases of genital chlamydia notified in the NT in this reporting period, which gave an annualised rate of 722.1 per 100,000 population (Table 1.1).
For the whole year of 2005, there were 1597 notifications and the notification rate was 787.7 per 100,000. Unlike gonorrhoea, the rate of chlamydia had remained generally stable, though extremely high, in the past three years after a sharply increasing trend seen during the preceding three years (2000-2003, Fig. 1.1).
Females represented about 61.2% of all cases and the male to female ratio was 1:1.58 (Table 1.2). 57.0% of all notifications were Aboriginal, about 1.8 times the number of non- Aboriginal notifications, although the annualised rate for Aboriginals was 4.6 times the non- Aboriginal rate (Table 1.3). They were 7.8 and 1.7 times the national rate (186.1 per 100,000 in 2004), respectively.
In this reporting period, Darwin recorded the highest number of notifications (304 cases, or 41.5% of all cases), but the highest annualised rate was recorded in East Arnhem (1313.6, see Table 1.4 & Fig. 1.4).
The younger age groups continued to record the highest case numbers and age-specific rates (Table 1.5 & Fig. 1.5). The 15 to 24 year age groups represented about 58.1% of all cases and recorded the highest rate of all age groups (about 2,700 per 100,000, or, 2.7%).
Darwin Rural Area recorded a slightly higher rate than that for Darwin Urban Area, though there were far more notifications in Darwin Urban Area (about six times higher); this was also true for Alice Springs District (Table 2.1 and Fig. 2.1).
B.3 Syphilis
In this reporting period, 110 syphilis notifications were recorded (excluding congenital syphilis, Table 1.1). In 2005, there were 231 notifications of syphilis and the annual rate was 113.9 per 100,000, which was consistent with a decreasing trend noticed in the last 5 years, despite a concurrent increasing trend for gonorrhoea and chlamydia. However, such rate was still over ten times higher than the national rate (less than 10 per 100,000 in 2004).
The numbers and rates of notifications for males and females were roughly the same (Table 1.2). Aboriginal population accounted for 90.9% of the total notifications (Table 1.3). 37.3%
of notifications were from Alice Springs, followed by Darwin (25.5%) and Katherine (19.1%,
Table 1.4). The annualised notification rates were highest in East Arnhem and Katherine, about five times that for Darwin.
The highest case numbers and rates were recorded in the 15 to 24 years age groups (representing 35.5% of all syphilis notifications, see Table 1.5).
There was one notification of congenital syphilis in these two quarters, which gave the total of 5 for 2005. All of these cases were Aboriginal.
B.4 Trichomoniasis
451 notifications of Trichomoniasis were recorded in this reporting period, which gave an annualised notification rate of 444.9 per 100,000 (Table 1.1). There were a total of 816 notifications in 2005, representing a 45.7% increase over 2004 (560 notifications).
Females represented 98.7% of all notifications (Table 1.2) and 92.9% were Aboriginals (Table 1.3). The notification rate for Aboriginal population remained about 50 times that for non-Aboriginals. Alice Springs District accounted for 45.0% of all cases, followed by East Arnhem and Darwin (23.3% and 22.0% respectively, see Table 1.4). However, in terms of notification rate, East Arnhem had recorded the highest rate (1483.1 per 100,000), followed by Alice Springs (1006.0 per 100,000). Similar to other notifiable STIs, the majority of the cases (39.5%) and the highest age-specific rates were recorded in the 15 to 24 year age groups (Table 1.5).
B.5 Donovanosis
One notification of donovanosis was recorded in this reporting period. The total for 2005 was 4, all of which were Aboriginal females. As shown in Fig.3.1, the annual number of notifications of donovanosis has generally remained below 10 since 1999 (except 2001 in which there were 13 notifications).
B.6 Other Sexually Transmitted Infections
There were no notifications of chancroid or lymphogranuloma venereum in this reporting period.
B.7 Hepatitis C
129 notifications of hepatitis C were recorded in this reporting period (Table 4.1). The total number for 2005 was 278, which was slightly higher than the 2004 total (265) and consistent with an increasing trend seen in recent 4 years (Fig. 4.1). The annual notifications rate for Unspecified Hepatitis C for the NT in 2005 (127.8 per 100,000) was considerably higher than the corresponding national rate (71.6 per 100,000 in 2005).
The vast majority were categorised as ‘unspecified’ (97.6%, see Table 4.2). As the NT is yet to implement enhanced surveillance of hepatitis C, it is not known whether the increasing trend mentioned above was the result of a true increase in incidence or due to other reasons.
The male to female rate ratio was 1.5:1, and. 63.6% of all notifications were non-Aboriginal (Table 4.1). About 80% of all notifications were recorded in Darwin District. This gave an annualised notification rate of 164.6 per 100,000 (Table 4.3), more than double the national rate.
While the majority of male cases occurred in 40-54 years age groups, in females the 40-49 age groups had the highest numbers of notifications (Table 4.4). Overall, the highest numbers and rates were recorded in 40-49 years age groups. This is dramatically different from the national statistics in which the 20-39 years age groups consistently record highest diagnosis rates among all age groups.
B.8 Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS)
There were in total four HIV notifications in 2005, all being non-Aboriginal. Among them, two were male homosexual, one was heterosexual and one was heterosexual and injection drug user. Two of them were not NT residents. There were no cases of AIDS notified.
6. Consumer response
The Sexual Health and BBV Unit is interested in readers’ responses to this report. Please forward all comments or suggestions to:
Surveillance Project Officer Acting Head of Sexual Health and BBV Unit
Jiunn-yih Su Dr. Steven Skov
Sexual Health and BBV Unit, Centre for Disease Control
Department of Health and Community Services PO Box 40596, Casuarina
Northern Territory Phone: (08) 89228874 Fax: (08) 8922 8809
Email: [email protected], [email protected]
All data in this report are provisional and subject to future revision.
This report is downloadable in PDF format from the Department of Health and Community Services website
: http://www.health.nt.gov.au/
Suggested citation:
Sexual Health and Blood Borne Viruses Unit Surveillance Update, Department of Health and Community Services, NT, 2005; Vol. 6, No. 2.
1. Sexually transmissible infections (STIs)
Table 1.1 Notifications of gonorrhoea, chlamydia, syphilis and trichomoniasis, number and rate per 100,000 population, Northern Territory, July-September & October- December, 2005
Gonorrhoea Chlamydia Syphilis Trichomoniasis Quarter
Cases Rate Cases Rate Case Rate Case Rate 2005
Jan-Mar 441 870.1 386 761.6 45 88.8 167 329.5 Apr-Jun 558 1100.9 479 945.1 76 149.9 198 390.7 Subtotal 999 985.5 865 853.3 121 119.4 365 360.1 Jul-Sep 380 749.7 335 661.0 51 100.6 201 396.6 Oct-Dec 367 724.1 397 783.3 59 116.4 250 493.3 Subtotal 747 736.9 732 722.1 110 108.5 451 444.9 2005 NT total 1746 861.2 1597 787.7 231 113.9 816 402.5
Figure 1.1 Notification rates of gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, 2000-2005
0 100 200 300 400 500 600 700 800 900 1000
Gonorrhoe a
Chlamy dia
Syp hilis
Tric homo
nias is Cases per 100,000
population 2000 2001 2002 2003 2004 2005
Table 1.2 Notification of gonorrhoea, chlamydia, syphilis and trichomoniasis, number and rate per 100,000 population, Northern Territory, by gender, July-December, 2004 and 2005
Gonorrhoea Chlamydia Syphilis Trichomoniasis Gender
Cases Rate Cases Rate Cases Rate Cases Rate Jul-Dec, 2005
Males
Jul-Sep 203 767.7 128 484.0 28 105.9 3 11.3 Oct-Dec 187 707.2 156 589.9 28 105.9 3 11.3 Total 390 737.4 284 537.0 56 105.9 6 11.3
Females
Jul-Sep 176 726.1 207 854.0 23 94.9 198 816.8 Oct-Dec 180 742.6 241 994.2 31 127.9 247 1019.0 Total 356 734.3 448 924.1 54 111.4 445 917.9
Unknown
Jul-Sep 1 0 0 0
Total 1 0 0 0
Jul-Dec, 2004
Males 345 656.1 300 570.5 65 123.6 2 3.8 Females 399 842.3 490 1034.4 64 135.1 264 557.3 2005 Whole Year
Males 875 832.0 583 554.3 129 122.7 9 8.6 Females 870 918.3 1014 1070.3 102 107.7 807 851.8
Unknown 1 0 0 0
Figure 1.2 Notification rates of Gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by gender, July-December, 2004 and 2005
0 200 400 600 800 1000 1200
Gonorrhoea Chlamydia Syphilis Trichomoniasis Cases per 100,000
population
Male Jul-Dec, 2004 Female Jul-Dec, 2004 Male Jul-Dec, 2005 Female Jul-Dec, 2005
Table 1.3 Notifications of gonorrhoea, chlamydia, syphilis and trichomoniasis, number and rate per 100,000 population, Northern Territory, by Indigenous status, July- December, 2004 and 2005
Ethnicity Gonorrhoea Chlamydia Syphilis Trichomoniasis Quarter Cases Rate Cases Rate Cases Rate Cases Rate
Aboriginal
Jul-Sep 326 2262.2 202 1401.7 48 333.1 182 1262.9 Oct-Dec 301 2088.7 215 1491.9 52 360.8 237 1644.6 Total 627 2175.4 417 1446.8 100 347.0 419 1453.8 Non-Aboriginal
Jul-Sep 34 93.7 105 289.5 1 2.8 11 30.3 Oct-Dec 51 140.6 125 344.6 7 19.3 10 27.6
Total 85 117.2 230 317.0 8 11.0 21 28.9 Unknown
Jul-Sep 20 28 2 8 Oct-Dec 15 57 0 3
Total 35 85 2 11 Jul-Dec, 2004
Aboriginal 630 2215.0 504 1772.0 58 203.9 256 900.0 Non-Aboriginal 70 97.9 210 293.7 12 16.8 9 12.6
Unknown 44 76 4 1
Figure 1.3 Notification rates of Gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by indigenous status, July-December 2005
0 500 1000 1500 2000 2500
Gonorrhoea Chlamydia Syphilis Trichomoniasis Cases per 100,000
population
Aboriginal Jul-Dec, 2004 Non-Aboriginal Jul-Dec, 2004 Aboriginal Jul-Dec, 2005 Non-Aboriginal Jul-Dec, 2005
Table 1.4 Notification rates of gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by district, July-September & October-December 2005
Gonorrhoea Chlamydia Syphilis Trichomoniasis District Cases Rate Cases Rate Cases Rate Cases Rate Darwin
Jul-Sep 97 313.1 120 387.4 13 42.0 50 161.4 Oct-Dec 119 384.2 184 594.0 15 48.4 49 158.2 Total 216 348.7 304 490.7 28 45.2 99 159.8 Katherine
Jul-Sep 38 812.4 31 662.7 15 320.7 19 406.2 Oct-Dec 53 1133.0 49 1047.5 6 128.3 21 448.9
Total 91 972.7 80 855.1 21 224.5 40 427.6 East Arnhem
Jul-Sep 27 762.7 42 1186.4 3 84.7 39 1101.7 Oct-Dec 31 875.7 51 1440.7 13 367.2 66 1864.4 Total 58 819.2 93 1313.6 16 226.0 105 1483.1 Barkly
Jul-Sep 13 927.6 5 356.8 0 0.0 2 142.7 Oct-Dec 11 784.9 7 499.5 4 285.4 2 142.7 Total 24 856.2 12 428.1 4 142.7 4 142.7 Alice Springs
Jul-Sep 205 2031.9 137 1357.9 20 198.2 91 902.0 Oct-Dec 153 1516.5 106 1050.6 21 208.1 112 1110.1
Total 358 1774.2 243 1204.3 41 203.2 203 1006.0
Figure 1.4 Notification rates of gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by district, July-December 2005
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Darwin Katherine East Arnhem Barkly Alice Springs Cases per 100,000
population Gonorrhoea Chlamydia Syphillis Trichomoniasis
Table 1.5 Notification of gonorrhoea, chlamydia, syphilis and trichomoniasis, number and annualised rate per 100,000 population, Northern Territory, by five-year age group, July-December 2005
Gonorrhoea Chlamydia Syphilis Trichomoniasis Age group Cases Rate Cases Rate Cases Rate Cases Rate Jul-Dec 2005
0-4 6 67.2 6 67.2 0 0.0 1 11.2 5-9 2 23.8 2 23.8 0 0.0 0 0.0 10-14 18 218.7 18 218.7 0 0.0 8 97.2 15-19 171 2306.4 187 2522.3 17 229.3 90 1213.9 20-24 203 2510.4 238 2943.2 22 272.1 88 1088.2 25-29 105 1234.1 130 1528.0 11 129.3 52 611.2 30-34 95 1040.0 61 667.8 14 153.3 53 580.2 35-39 69 810.5 43 505.1 9 105.7 64 751.8 40-44 30 371.2 24 297.0 16 198.0 36 445.5 45-49 28 394.3 11 154.9 8 112.7 31 436.6 50-54 12 187.6 4 62.5 5 78.2 16 250.1 55-59 5 100.4 7 140.6 4 80.4 9 180.8
60-64 1 31.1 0 0.0 2 62.3 3 93.4
65+ 2 45.7 1 22.8 2 45.7 0 0.0 Total 747 736.9 732 722.1 110 108.5 451 444.9
Figure 1.5 Annualised notification rates of Gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by five-year age group, July-December 2005
0 500 1000 1500 2000 2500 3000 3500
0-4 5-9 10- 14
15- 19
20- 24
25- 29
30- 34
35- 39
40- 44
45- 49
50- 54
55- 59
60- 64
65+
Case per 100,000
population Gonorrhoea Chlamydia Syphilis Trichomoniasis
2. Urban and Rural Burden of Disease
Table 2.1 Notifications of gonorrhoea, chlamydia syphilis and trichomoniasis, number and rate per 100,000 population, Northern Territory, by urban and rural split by district, July-September & October-December 2005
Gonorrhoea Chlamydia Syphilis Trichomoniasis District Cases Rate Cases Rate Cases Rate Cases Rate Darwin Urban
Jul-Sep 57 207.5 98 356.8 5 18.2 23 83.7 Oct-Dec 83 302.2 162 589.8 8 29.1 17 61.9
Total 140 254.8 260 473.3 13 23.7 40 72.8 Darwin Rural
Jul-Sep 38 1083.6 19 541.8 8 228.1 26 741.4 Oct-Dec 34 969.6 19 541.8 8 228.1 29 827.0
Total 72 1026.6 38 541.8 16 228.1 55 784.2 Alice Springs Urban
Jul-Sep 83 1202.4 62 898.2 9 13.0 27 391.1 Oct-Dec 84 1216.9 69 999.6 12 17.4 27 391.1 Total 167 1209.6 131 948.9 21 13.0 54 391.1 Alice Springs Rural
Jul-Sep 110 3452.6 66 2071.6 8 251.1 63 1977.4 Oct-Dec 45 1412.4 22 690.5 10 313.9 49 1538.0
Total 155 2432.5 88 1381.0 18 282.5 112 1757.7
*Figures shown here may be different from District totals in Table 1.4. This is because interstate cases and visitors may be notified under Alice Springs or Darwin Districts
Figure 2.1 Notification rates of gonorrhoea, chlamydia, syphilis and trichomoniasis, Northern Territory, by Urban and Rural split by district, July-December 2005
0 500 1000 1500 2000 2500 3000
Darwin Urban Darwin Rural Alice Springs Urban Alice Springs Rural Cases per
100,0000 population
Gonorrhoea Chlamydia Syphillis Trichomoniasis
3. Donovanosis
Figure 3.1 Annual number of notifications of Donovanosis, Northern Territory, 1991- 2005
0 10 20 30 40 50 60 70 80
1991 1992 1993 1994 1995 1996
1997
1998 1999 2000 200 1
2002 2003 2004 2005 Year
Number of Notifications
4. Hepatitis C
Table 4.1 Notifications of hepatitis C, number and rate per 100,000 population, Northern Territory, by gender and indigenous status, July-December 2005
Quarter Gender Aboriginal Non-Aboriginal Unknown Total Case Rate Case Rate Case Case Rate
Jul-Sep Female 3 41.5 20 117.5 9 32 132.0
Male 0 0.0 24 124.6 9 33 124.8
Total 3 20.8 44 121.3 18 65 128.2
Oct-Dec Female 3 41.5 13 76.4 3 19 78.4
Male 2 27.8 25 129.8 18 45 170.2
Total 5 34.7 38 104.8 21 64 126.3
Jul-Dec Female 6 41.5 33 97.0 12 51 105.2 Male 2 13.9 49 127.2 27 78 147.5
Total 8 27.8 82 113.0 39 129 127.3
Table 4.2 Number of notifications of hepatitis C, Northern Territory, by hepatitis category, indigenous status and gender, July-December 2005
Indigenous status Type
Gender
Aboriginal Non-
Aboriginal Unknown
Total Percentage
Female 1 0 0 1
Chronic
Male 0 0 0 0 0.8%
New Female 0 2 0 2 1.6%
Female 5 31 12 48
Unspecified
Male 2 49 27 78 97.6%
Total 8 82 39 129
Figure 4.1 Annual number of notifications of hepatitis C (unspecified), Northern Territory, 1995-2005
0 50 100 150 200 250 300 350
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year
Annual number of notifications
Table 4.3 Notifications of hepatitis C, number and rate per 100,000 population, Darwin and Alice Springs District, by gender, July-December 2005
District
Darwin Alice Springs Gender
Case Rate Case Rate Female 38 64.5 8 40.6 Male 64 98.4 7 33.9 Total 102 164.6 15 74.3
Figure 4.2 Notification rate of hepatitis C, Darwin and Alice Springs District, by gender, July-December 2005
0 20 40 60 80 100 120 140 160 180
Darwin Alice Springs
Cases per 100,000
population Female Male All
Table 4.4 Notifications of hepatitis C, number and rate per 100,000 population, Northern Territory, by five-year age group and gender, July-December 2005
Female Male Total Age group
Case Rate Case Rate Case Rate
0-4 0 0.0 0 0.0 0 0.0
5-9 0 0.0 0 0.0 0 0.0
10-14 0 0.0 0 0.0 0 0.0 15-19 2 56.5 2 51.6 4 54.0 20-24 5 129.1 3 71.2 8 98.9 25-29 7 172.1 7 157.6 14 164.6 30-34 8 177.1 11 238.2 19 208.0 35-39 7 168.8 10 229.0 17 199.7 40-44 9 232.9 14 332.0 23 284.6 45-49 9 260.6 13 356.4 22 309.8 50-54 3 99.2 11 326.0 14 218.8 55-59 0.0 5 182.5 5 100.4 60+ 1 29.2 2 47.9 3 39.5 Total 51 96.4 78 76.9 129 127.3
Figure 4.3 Notification rate of hepatitis C, Northern Territory, by five-year age group, July-December 2005
0 50 100 150 200 250 300 350 400
0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60+
Age group
Cases per 100,000
population Female Male All
