Results - continued

Sexually transmissible infections

Introduction

In 2012, the STIs reported to the NNDSS were chlamydia, donovanosis, gonorrhoea and syphilis. Other national surveillance systems that monitor STIs in Australia include the Australian Gonococcal Surveillance Programme (AGSP), which is a network of specialist laboratories monitoring antimicrobial susceptibility patterns of gonococcal infection; and The Kirby Institute for Infection and Immunity in Society.

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Chlamydial infection

Genital chlamydia infection is caused by the bacterium Chlamydia trachomatis serogroups D to K. Screening is important in detecting chlamydia infections, as a large proportion of infections are asymptomatic.³⁸ If infection is left untreated, complications such as epididymitis in men and infertility and pelvic inflammatory disease in females can arise.¹⁹

Epidemiological situation in 2012

Chlamydial infection was the most frequently notified disease to the NNDSS (34% of all notifications in 2012), with 82,707 cases (364 per 100,000) notified in 2012. Between 2011 and 2012, the notification rate of chlamydial infection increased by less than 1% (362 and 364 per 100,000 respectively), while between 2007 and 2011, notification rates increased by 47% (247 and 362 respectively) (Figure 16).

Figure 16: Notifications and notification rates per 100,000 for chlamydial infection, Australia, 2007 to 2012, by year

Text version of Figure 16 (TXT 1 KB)

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Geographical distribution

In 2012, the notification rate of chlamydial infection was almost 3 times higher in the Northern Territory (1,077 per 100,000) than nationally (364 per 100,000). In the remaining jurisdictions notification rates ranged between 292 per 100,000 in New South Wales and 485 per 100,000 in Western Australia (Figure 17).

Figure 17: Notifications and notification rates for chlamydial infection, Australia, 2012, by state or territory

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All states and territories have seen overall increases in notification rates from 2007 to 2012, but only New South Wales and Victoria have seen increases in every year. During the same period, only the Northern Territory and Queensland have maintained a decline in rates over more than 1 year.

Age and sex distribution

Nationally in 2012, the notification rate for chlamydial infection was 307 per 100,000 in males, and 419 per 100,000 in females. In 2012, chlamydial infection occurred predominately among those aged 15–29 years, accounting for 80% of notified cases.

In total, the female to male rate ratio in 2012 was 1.36:1, slightly lower than the preceding 5-year mean of 1.43:1. In 2012, notification rates in females exceeded those in males under the age of 30 years, especially in the 10–14 years age group (Figure 18). The overall higher rate among females may be partly attributable to preferential testing of women attending health services compared with men.^8,26

Figure 18: Notification rate for chlamydial infection, Australia, 2012, by age group and sex*

* Excludes notifications for whom age and/or sex were not reported and notifications where the case was aged less than 13 years.

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When considering trends over time in those aged 15–39 years, notification rates increased almost every year, for all age groups and for both sexes (Figure 19). The exceptions were between 2011 and 2012, when rates declined in males aged 15–19 years and 20–25 years, and females aged 15–19 years.

Figure 19: Notification rate for chlamydial infection in persons aged 15–39 years, Australia, 2007 to 2012, by year, sex* and age group

* Excludes notifications for whom age and/or sex were not reported.

Text version of Figure 19 (TXT 1 KB)

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Indigenous population

The completeness of Indigenous status identification in the notification data varies by year and by jurisdiction. Nationally in 2012, data on Indigenous status were complete in 51% of notifications, slightly higher than the preceding 5-year mean of 49% (range: 44%–51%). Four jurisdictions had greater than 50% completeness of the Indigenous status field across the 2007 to 2012 period: the Northern Territory, South Australia, Tasmania, and Western Australia. Among these jurisdictions, the combined age-standardised notification rate ratio between Indigenous and non-Indigenous populations in 2012 was 3.6:1. Overall, this rate ratio has declined by 28% from 2007 (4.9:1) to 2012 (3.6:1).

Among the Indigenous population, the age-standardised notification rate declined from 1,344 per 100,000 in 2011 to 1,252 per 100,000 in 2012. This followed increases in 2009, 2010 and 2011 (1,115, 1,321 and 1,344 per 100,000 respectively), which in turn followed a decline in 2008 (1,180 per 100,000).

Age-standardised notification rates among the non-Indigenous population have increased by 47% from 2007 (240 per 100,000) to 2012 (352 per 100,000). The average annual increase over this period was 8% (range: 2%–13%).

In terms of geographical trends, age-standardised notification rates of chlamydial infection in the Indigenous population declined from 2011 to 2012, in all 4 states and territories in which Indigenous status was more than 50% complete across 2007 to 2012. Age-standardised notification rates decreased in the Northern Territory by 12% (from 1,758 to 1,542 per 100,000), in Tasmania by 5% (from 141 to 134 per 100,000), in South Australia by 4% (from 748 to 719 per 100,000), and in Western Australia by 2% (from 1,533 to 1,504 per 100,000).

Between 2011 and 2012, the age-standardised notification rates of chlamydial infection in the non-Indigenous population increased by 5% in the Northern Territory (from 623 to 653 per 100,000) and by 2% in Tasmania (from 395 to 401 per 100,000). During the same period, age-standardised non-Indigenous notification rates decreased by 6% in South Australia (from 314 to 294 per 100,000) and by 2% in Western Australia (from 430 to 422 per 100,000) (Figure 20).

Figure 20: Age standardised notification rates of chlamydial infection, selected states and territories,* 2007 to 2012, by year and Indigenous status

* Includes the states and territories where Indigenous status was reported for more than 50% of cases between 2007 and 2012: the Northern Territory, South Australia, Tasmania and Western Australia.

Text version of Figure 20 (TXT 1 KB)

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Donovanosis

Donovanosis, caused by the bacterium Klebsiella granulomatis, is a chronic, progressively destructive infection that affects the skin and mucous membranes of the external genitalia, inguinal and anal regions.³⁹ Donovanosis was targeted for elimination in Australia through the National Donovanosis Elimination Project 2001–2004.⁴⁰ The disease predominantly occurred in Aboriginal and Torres Strait Islander females in rural and remote communities in central and northern Australia. It is now rare, with an average of 7 cases notified each year since 2002, and only 5 cases notified in the 5 years from 2008 to 2012.

Epidemiological situation in 2012

In 2012, 1 case of donovanosis was notified in a non-Indigenous male (Figure 21).

Figure 21: Notifications of donovanosis, Australia, 1991 to 2012, by year

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Gonococcal infection

Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae, which infects mucous membranes causing symptomatic and asymptomatic genital and extragenital tract infections.¹⁹ If left untreated, it can lead to pelvic inflammatory disease in women and infertility in both men and women. Gonococcal infection also increases the risk of both acquisition and transmission of HIV.³⁹

Epidemiological situation in 2012

In 2012, there were 13,649 cases of gonococcal infection reported to the NNDSS, a notification rate of 60 per 100,000. This was an 11% increase compared with the rate reported in 2011 (54 per 100,000). Notification rates were stable from 2007 to 2008 (36 per 100,000) and then increased in all subsequent years to 2012 by an average of 14% each year (range: 7%–23%). Overall, notification rates increased by 66% from 2007 (36 per 100,000) to 2012 (60 per 100,000) (Figure 22).

Figure 22: Notifications and notification rate for gonococcal infection, Australia, 2007 to 2012, by year

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Geographical distribution

In 2012, the notification rate of gonococcal infection was more than 18 times higher in the Northern Territory (653 per 100,000) than nationally (36 per 100,000). The next highest notification rates were in Western Australia (87 per 100,000), then Queensland (59 per 100,000), New South Wales (57 per 100,000), Victoria (45 per 100,000), South Australia (30 per 100,000), the Australian Capital Territory (25 per 100,000), and Tasmania (9 per 100,000).

Between 2011 and 2012, rates increased in New South Wales (from 40 to 57 per 100,000), South Australia (from 27 to 30 per 100,000), Victoria (from 34 to 45 per 100,000) and Western Australia (from 78 to 87 per 100,000) and declined in the Australian Capital Territory (from 35 to 25 per 100,000), the Northern Territory (from 844 to 653 per 100,000), and Queensland (from 66 to 59 per 100,000). Between 2007 and 2012, all states and territories have seen overall increasing rates of gonococcal infection have been observed in all states and territories, except for the Northern Territory and Tasmania.

Age and sex distribution

Nationally in 2012, the notification rate for gonococcal infection was 84 per 100,000 in males and 36 per 100,000 in females. In males, this was an increase of 16% compared with the 2011 notification rate (73 per 100,000) and in females, this was an increase of 2% compared with the 2011 notification rate (35 per 100,000). In 2012, gonococcal infection occurred predominately among those aged 15–34 years, who accounted for 72% of notified cases.

Across all age groups, the male to female ratio was 2.4:1 in 2012. This was similar to the ratios in the past 5 years. In 2012, notification rates in males exceeded those in females in all age groups above 20 years, especially in the 40–45 years age group (Figure 23).

Figure 23: Notification rate for gonococcal infection, Australia, 2012, by age group and sex*

* Excludes notifications for whom age and/or sex were not reported and notifications where the case was aged less than 13 years and the infection was able to be determined as non-sexually acquired.

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From 2010 to 2012, notification rates then increased in all age groups across both sexes, with the exception of females aged 15–19 years and 25–29 years where rates declined from 2011 to 2012 (Figure 24).

Figure 24: Notification rate for gonococcal infection in persons aged 15–49 years, Australia, 2007 to 2012, by year, sex and age group*

* Excludes notifications for whom age and/or sex were not reported.

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Indigenous population

The completeness of Indigenous status information in the notification data varies by year and jurisdiction. Nationally in 2012, data on Indigenous status were complete for 65% of notifications, which was lower than the preceding 5-year mean of 69% (range: 68%–73%). All states and territories except New South Wales and the Australian Capital Territory had greater than 50% completeness for the Indigenous status field across the 2007 to 2012 period. The Australian Capital Territory has had greater than 50% completeness since 2008, with 100% completeness from 2010 to 2012. Among these states and territories, the combined age-standardised notification rate ratio between Indigenous and non-Indigenous populations in 2012 was 18.9:1, declining from 27.7:1 in 2011. Overall, the rate ratio has declined by 53% from 2007 to 2012 (from 40.2:1 to 18.9:1).

Among the Indigenous population, the age-standardised notification rate declined in 2012 from 2011 (from 876 to 724 per 100,000). The rates in 2012 were 9% lower than in 2007 (793 per 100,000).

The age-standardised notification rate among the non-Indigenous population almost doubled from 2007 to 2012 (20 and 38 per 100,000 respectively). The average annual increase over this period was 14% (range: 5%–21%).

In terms of geographical trends, age-standardised notification rates of gonococcal infection in the Indigenous population declined between 2011 and 2012 in most states and territories in which Indigenous status was more than 50% complete. Rates decreased in the Northern Territory by 26% (from 2,042 to 1,511 per 100,000), in Queensland by 17% (from 600 to 495 per 100,000), in South Australia by 10% (from 565 to 508 per 100,000), and in Western Australia by 5% (from 1,143 to 1,088 per 100,000). Tasmania reported no cases in Indigenous people in 2011 or 2012. The Indigenous notification rate in Victoria increased by 126% (from 28 to 63 per 100,000) (Figure 25).

Between 2011 and 2012, the age-standardised rates of gonococcal infection in the non-Indigenous population increased by 28% in the Northern Territory (from 95 to 121 per 100,000), by 32% in South Australia (from 15 to 19 per 100,000), by 92% in Tasmania (from 4 to 8 per 100,000), by 33% in Victoria (from 33 to 44 per 100,000), and by 41% in Western Australia (from 28 to 40 per 100,000) (Figure 25).

Figure 25: Age-standardised notification rate for gonococcal infection, selected states and territories,* 2007 to 2012, by year and Indigenous status

* Includes the states and territories where Indigenous status was reported for more than 50% of cases between 2007 and 2012: the Northern Territory, Queensland, South Australia, Tasmania, Victoria, and Western Australia.

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Microbiological trends

The AGSP is the national surveillance system for monitoring the antimicrobial resistance of N. gonorrhoeae isolates. These results are published in more details in the AGSP annual report in CDI.⁴¹

In 2012, the AGSP reported that a total of 4,784 gonococcal isolates were referred for antibiotic susceptibility testing, representing 35% of gonococcal infections notified to the NNDSS. This was similar to the proportion of NNDSS cases tested in 2011, but lower than the 40%–42% referred in 2008–2010. Of the 4,784 referred isolates, 4,718 remained viable for antibiotic susceptibility testing.

Eighty-one per cent of the viable isolates (n=3,860) were from males and 19% (n=924) were from females (M:F, 4.18:1). The proportion of gonococcal isolates from males and females tested by the AGSP has remained similar over recent years (<1% variation).

In 2012, all isolates from all states and territories were susceptible to the injectable antibiotic spectinomycin.

Syphilis (non-congenital categories)

Syphilis, caused by the bacterium Treponema pallidum, is characterised by a primary lesion, a secondary eruption involving skin and mucous membranes, long periods of latency and late lesions of skin, bone, viscera, cardiovascular and nervous systems.¹⁹

In 2004, all jurisdictions except South Australia began reporting non-congenital syphilis infections to the NNDSS separately categorised as: infectious syphilis (primary, secondary or early latent) of less than 2 years duration; and syphilis of more than 2 years or unknown duration. From 2004 to 2011, South Australia reported only cases of infectious syphilis, and then in 2012 commenced reporting syphilis of more than 2 years or unknown duration. Data for all states and territories are reported by diagnosis date, except Queensland, which is reported by notification receive date.

Epidemiological situation in 2012

In 2012, a total of 2,893 cases of syphilis (non-congenital) were reported. This represents a rate of 12.7 per 100,000, a 6% increase compared with 2011 (12.0 per 100,000) (Table 6, Figure 26). A very small portion of this increase was due to the fact that in 2012 South Australia commenced reporting syphilis cases of more than 2 years or unknown duration. In 2012, 47% of syphilis notifications were categorised as greater than 2 years or unknown duration, and 53% of cases were categorised as less than 2 years duration.

Figure 26: Notification rate for non-congenital syphilis infection* (all categories), Australia,^† 2007 to 2012, by year and category

* For infectious syphilis, excludes notifications where the case was aged less than 13 years and the infection was able to be determined as non-sexually acquired. For syphilis of more than 2 years or unknown duration, excludes all notifications where the case was aged less than 13 years.

† For syphilis of more than 2 years or unknown duration, excludes South Australia from 2007 to 2011.

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Syphilis – infectious (primary, secondary and early latent), less than 2 years duration

Epidemiological situation in 2012

In 2012, 1,539 notified cases of infectious syphilis (primary, secondary and early latent), less than 2 years duration, were reported to the NNDSS, representing a rate of 6.8 per 100,000. This was a 16% increase compared with the rate reported in 2011 (5.9 per 100,000) (Table 6, Figure 26). The notification rate for infectious syphilis declined by 26% from 2007 to 2010 (from 6.6 to 5.1 per 100,000), increased by 16% in 2011, and again by 16% in 2012 (Figure 26).

Geographical distribution

In 2012, notification rates of infectious syphilis (less than 2 years duration) were highest in Queensland and Victoria (both 8.4 per 100,000) (Table 15). Between 2007 and 2011, the Northern Territory consistently reported the highest rate of notifications compared with other states and territories. However, rates in the Northern Territory declined by almost 90% from 2007 (54.9 per 100,000) to 2011 (13.0 per 100,000) before halving again in 2012 (6.0 per 100,000).

Table 15: Notifications and notification rates for syphilis less than 2 years duration, Australia, 2012, by state or territory and sex

State or territory	Male		Female		Total*
	Notifications	Notification rate‡	Notifications	Notification rate‡	Notifications	Notification rate‡
* Includes notifications for whom sex was not reported. † Per 100,000 population. ‡ Data reported by notification received date.
ACT	15	8.0	0	0.0	15	4.0
NSW	490	13.5	20	0.5	510	7.0
NT	9	7.3	5	4.5	14	6.0
Qld‡	306	13.4	77	3.4	383	8.4
SA	41	5.0	11	1.3	52	3.1
Tas.	13	5.1	1	0.4	14	2.7
Vic.	441	15.8	30	1.1	474	8.4
WA	69	5.6	8	0.7	77	3.2
Total	1,384	12.2	152	1.3	1,539	6.8

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Age and sex distribution

Nationally in 2012, the notification rate of infectious syphilis was 12.2 per 100,000 in males and 1.3 per 100,000 in females, equating to a male to female ratio of 9.2:1. In males, this was an increase of 21% when compared with the 2011 rate (10.1 per 100,000) and in females this was a decrease of 10% compared with the 2011 rate (1.5 per 100,000). The ratio of male to female notification rates increased by 35% compared with the 2011 ratio (6.8:1). In 2012, 78% of all notifications occurred in males aged 30 years or over, and notification rates in males exceeded those in females in almost all age groups (Figure 27). Diagnoses of infectious syphilis in 2012 were almost completely confined to men who have sex with men.⁴²

Figure 27: Notification rate for infectious syphilis (primary, secondary and early latent), less than 2 years duration, Australia, 2012, by age group and sex*

* Excludes notifications for whom age and/or sex were not reported and notifications where the case was aged less than 13 years and the infection was able to be determined as non-sexually acquired.

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Notification rates for males aged 15 years or over declined overall among most age groups from 2007 to 2010. In 2011, notification rates in all age groups increased, and then in 2012, notification rates increased in all age groups except those aged 15–19 and 40–45 years (<1% increase) (Figure 28).

Figure 28: Notification rate for infectious syphilis (primary, secondary and early latent), less than 2 years duration, in persons aged 15 years or over,* Australia, 2007 to 2012, by year, sex* and age group

* Excludes notifications for whom age and/or sex were not reported.

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In females, notification rates between 2007 and 2012 have averaged 1.3 per 100,000 (range: 1.1–1.5). There was a notable increase among those aged 15–19 years from 2010 (1.8 per 100,000) to 2011 (6.1 per 100,000).

Indigenous population

The completeness of Indigenous status identification in the notification data varies by year and by jurisdiction. Nationally in 2012, data on Indigenous status were complete for 93% of notifications, a slight decrease compared with 2011 (95% complete) and slightly lower than the preceding 5-year mean of 95% (range: 94.6%–96.5%). All states and territories except the Australian Capital Territory had greater than 50% completeness for the Indigenous status field across the 2007 to 2012 period.

Among these states and territories, the combined age standardised notification rate ratio between the Indigenous and non-Indigenous populations in 2012 was 4.0:1, which is lower than the preceding 5-year mean of 5.4:1 (range: 4.4–6.0).

The age-standardised notification rate in the Indigenous population declined from 30.0 per 100,000 in 2011 to 24.1 per 100,000 in 2012. This follows decreases in 2008, 2009 and 2010 (31.7, 24.8 and 24.2 per 100,000 respectively). Overall, the rate in 2012 was 29% lower than the 2007 rate (33.7 per 100,000). The age-standardised notification rate among the non-Indigenous population increased from 5.1 per 100,000 in 2011 to 6.2 per 100,000 in 2012. This follows a decrease in 2010 (4.5 per 100,000), an increase in 2009 (5.6 per 100,000), and a decline in 2008 (5.4 per 100,000). The rate in 2012 is 6% higher than it was in 2007 (5.9 per 100,000).

In terms of geographical trends, from 2011 to 2012, age-standardised rates of syphilis in the Indigenous population declined in all states and territories except New South Wales (Figure 29). Between 2007 and 2012, the Northern Territory was the only jurisdiction to report declining Indigenous age-standardised notification rates every year. The increase evident in Indigenous notification rates in Western Australia in 2008 was largely attributable to an outbreak that occurred in the Pilbara region among Aboriginal people during that year.⁴³

Among the non-Indigenous population between 2011 and 2012, age-standardised rates of syphilis infection increased in all jurisdictions, except the Northern Territory and Western Australia (Figure 29).

Figure 29: Age-standardised notification rates of infectious syphilis (primary, secondary and early latent), less than 2 years duration, selected states and territories,* 2007 to 2012, by year and Indigenous status

* Includes the states and territories where Indigenous status was reported for more than 50% of cases between 2007 and 2012: New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, and Western Australia.

Text version of Figure 29 (TXT 1 KB)

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Syphilis of more than 2 years or unknown duration

Epidemiological situation in 2012

In 2012, 1,354 cases of syphilis of more than 2 years or unknown duration were reported to the NNDSS. This represents a notification rate of 6.0 per 100,000, a decrease of 3% compared with 2011 (6.2 per 100,000) (Table 6, Figure 26). The notification rate of syphilis of more than 2 years or unknown duration increased by 1% between 2007 and 2008 (6.8 and 6.9 respectively), by 2% in 2009 (7.0 per 100,000), then declined by 10% in 2010 (6.3 per 100,000), and by 2% in 2011 (6.2 per 100,000) (Figure 26). Overall, notification rates have declined by 13% from 2007 to 2012 (6.8 to 6.0 per 100,000).

Geographical distribution

In 2012, notification rates of syphilis of more than 2 years or unknown duration were highest in the Northern Territory (28.5 per 100,000), followed by Victoria (9.0 per 100,000) (Table 16).

Table 16: Notifications and notification rates for syphilis (more than 2 years or unknown duration), Australia, 2012, by state or territory and sex

State or territory	Male		Female		Total*
	Notifications	Notification rate‡	Notifications	Notification rate‡	Notifications	Notification rate‡
* Includes notifications for whom sex was not reported. † Per 100,000 population. ‡ By notification received date.
ACT	11	5.9	2	1.1	13	3.5
NSW	195	5.4	88	2.4	283	3.9
NT	62	50.2	5	4.5	67	28.5
Qld‡	158	6.9	98	4.3	256	5.6
SA	49	6.0	30	3.6	79	4.8
Tas.	5	2.0	5	1.9	10	2.0
Vic.	350	12.6	149	5.2	506	9.0
WA	98	8.0	42	3.5	140	5.8
Total	928	8.2	419	3.7	1,354	6.0

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Age and sex distribution

Nationally in 2012, the notification rate of syphilis of more than 2 years or unknown duration was 8.2 per 100,000 in males and 3.7 per 100,000 in females; a male to female ratio of 2.2:1. In males, this was an increase of 8% when compared with the 2011 rate (7.6 per 100,000), and in females this was a decrease of 4% compared with the 2011 rate (3.8 per 100,000). Almost 70% of all notifications occurred in males aged 20 years or over, and notification rates in males exceeded those in females in all age groups (Figure 30).

Figure 30: Notification rate for syphilis of more than 2 years or unknown duration, Australia,* 2012, by age group and sex

* Excludes notifications for whom age and/or sex were not reported and notifications where the case was aged less than 13 years.

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Notification rates for those aged 15 years or over from 2007 to 2012 increased overall in most age groups for males, and declined overall across age groups for females (Figure 31).

Figure 31: Notification rate for syphilis of more than 2 years or unknown duration, in persons aged 15 years or over,* Australia,^† 2007 to 2012, by year, sex and age group

* Excludes notifications for whom age and/or sex were not reported.

† Data from all states and territories except South Australia in 2007–2011.

Text version of Figure 31 (TXT 1 KB)

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Congenital syphilis

Congenital syphilis is caused by foetal infection with the bacterium T. pallidum. Syphilis is acquired by infants either in-utero or at birth from women with untreated early infection. Infections commonly result in abortion or stillbirth and may cause the death of a newborn infant. Congenital syphilis can be asymptomatic, especially in the first weeks of life.¹⁹

Epidemiological situation in 2012

There were no notifications of congenital syphilis in 2012, continuing the downward trend observed over the past decade (Figure 32). Antenatal screening for syphilis with follow up and adequate treatment is considered to be a contributor to this decline.⁴⁴

Figure 32: Notifications of congenital syphilis, Australia, 2002 to 2012, by year

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