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Introduction | Methods | Results - Part 1 | Appendices | Acknowledgements and abbreviations| References
Results part 2: Bloodborne diseases | Gastrointestinal | Quarantinable | Sexually transmissible | Vaccine preventable | Vectorborne | Zoonoses | Other bacterial infections
Results - Part 4
Sexually transmissible infections
In 2014, the STIs reported to the NNDSS were chlamydial infection, donovanosis, gonococcal infection, and congenital and non-congenital 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.
Chlamydial infection
In 2014, 86,108 cases of chlamydial infection were notified to the NNDSS.
Notification rates have remained relatively stable from 2011.
Almost 40% of notifications were among females aged 15–24 years.
Genital chlamydial infection is caused by the bacterium Chlamydia trachomatis serogroups D–K. Screening is important in detecting chlamydial infections, as a large proportion of infections are asymptomatic. Chlamydial infection is highly treatable, although reinfection is common.52 If left untreated, complications such as epididymitis in males and infertility and pelvic inflammatory disease in females can arise.22
Epidemiological situation in 2014
In 2014, chlamydial infection was the most frequently notified disease to the NNDSS, with 86,108 cases, representing 31% of all notifications reported to the NNDSS in 2014. Since 2011, notification rates have remained relatively stable, increasing marginally from 363.0 per 100,000 in 2011 to 366.8 per 100,000 in 2014. This follows a 25% increase in notification rates from 2009 to 2011 (291.4 to 363.0 per 100,000 respectively) (Figure 31).
Geographical distribution
In 2014, the notification rate for chlamydial infection was more than 3 times higher in the Northern Territory (1,225.2 per 100,000) than the overall national rate (366.8 per 100,000) (Figure 32). This is mostly explained by the ongoing disproportion of young Aboriginal and Torres Strait Islander women affected by chlamydial infection, particularly those living in regional and remote areas (Table 5).9
Age and sex distribution
In 2014, chlamydial infection occurred predominately in females aged 15–24 years, accounting for 38% of all chlamydial infections (Figure 33). Similar to 2013, the national notification rate for chlamydial infection in 2014 was 314.8 per 100,000 in males and 417.5 per 100,000 in females. The overall higher rate among females may be partly attributable to preferential testing of women attending health services compared with men.9,33 Notification rates for males and females increased overall from 2009 to 2014, by 31% (239.7 to 314.8) in males and 22% (340.9 to 417.5) in females, and across most age groups; however, rates decreased from 2011 and 2014 for females aged 15–19 years (Figure 34).
Indigenous status
The completeness of Indigenous status identification for chlamydial infection notification data varies by year and by jurisdiction. Nationally in 2014, data on Indigenous status were complete for 37% (31,990) of chlamydial infection notifications, which was lower than the preceding 5-year average of 48% (range: 39%–51%). Four jurisdictions had greater than 50% completeness of the Indigenous status field in each year during the 2009–2014 period: the Northern Territory, Queensland, South Australia, and Western Australia. Among these jurisdictions, the combined age-standardised notification rate ratio between Indigenous and non-Indigenous populations in 2014 was 3.5:1, which was similar to the previous 5 years (range: 3.4–3.7).
Among the Indigenous population, the age-standardised notification rate declined from 1,378.8 per 100,000 in 2011 to 1,266.4 per 100,000 in 2014. This followed an increase from 1,112.4 per 100,000 in 2009 to 1,332.2 per 100,000 in 2011.
Age-standardised notification rates among the non-Indigenous population increased overall from 313.1 per 100,000 in 2009 to 369.9 per 100,000 in 2014. The rate increased each year except for a small decline from 358.5 per 100,000 in 2011 to 355.2 per 100,000 in 2012.
Between 2013 and 2014, age-standardised notification rates for chlamydial infection in the Indigenous population decreased by 7% in both Queensland (1,271.0 to 1,179.8) and Western Australia (1,433.8 to 1,327.8), and by 2% (1,906.6 to 1,863.6) in the Northern Territory. Conversely, rates increased in South Australia by 17% (871.4 to 1,020.6).
Between 2013 and 2014, age-standardised notification rates for chlamydial infection in the non-Indigenous population decreased by 3% (387.8 to 374.3) in Western Australia, and by 2% in both South Australia (325.1 to 318.5) and the Northern Territory (481.0 to 472.0). Conversely, rates increased in Queensland by 6% (356.8 to 378.7) (Figure 35).
Donovanosis
In 2014, 1 case of donovanosis was notified to the NNDSS.
This disease remains rare in Australia.
Donovanosis, caused by the bacterium Klebsiella granulomatis, is a chronic, progressively destructive infection that is primarily transmitted through sexual exposure. It affects the skin and mucous membranes of the external genitalia, inguinal and anal regions.53 Once diagnosed, donovanosis is treated with a series of antibiotics.54
All donovanosis notifications in Australia since 1991 were reported either in the Northern Territory, Western Australia or Queensland and have predominately occurred in Aboriginal and Torres Strait Islander people living in remote areas in northern and central Australia.
Donovanosis was targeted for elimination in Australia through the National Donovanosis Elimination Project 2001–2004.55 It is now rare, with fewer than 17 cases notified each year since 2002, and fewer than 5 cases notified each year since 2007 (Figure 36).
Epidemiological situation in 2014
In 2014, 1 case of donovanosis was notified in Australia, in an Indigenous female from Western Australia (Figure 36).
Gonococcal infection
In 2014, 15,675 cases of gonococcal infection were notified to the NNDSS.
Notification rates for gonococcal infection continued to increase.
Notifications occurred predominately in males aged 15–39 years and females aged 15–24 years.
Gonococcal infection is caused by the bacterium Neisseria gonorrhoeae, which affects the mucous membranes causing symptomatic and asymptomatic genital and extra-genital tract infections. The most common source of transmission is via unprotected sexual intercourse with an infected person.22 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. 53
Epidemiological situation in 2014
In 2014, there were 15,675 cases of gonococcal infection reported to the NNDSS, a notification rate of 66.8 per 100,000. This was a 4% increase compared with the rate reported in 2013 (64.5 per 100,000). In the past 6 years, gonococcal infection notification rates increased, on average, 12% each year since 2009 (range: 4%–23%). Overall, gonococcal infection notification rates increased by 75% from 2009 (38.1 per 100,000) to 2014 (66.8 per 100,000) (Figure 37).
Geographical distribution
In 2014, the notification rate for gonococcal infection was almost 11 times higher in the Northern Territory (711.7 per 100,000) than the overall national rate (66.8 per 100,000) (Figure 38).
Age and sex distribution
Nationally in 2014, the notification rate for gonococcal infection was 97.9 per 100,000 in males and 35.3 per 100,000 in females. Notification rates in males increased by 8% and decreased in females by 7% when compared with 2013 (91.0 and 37.8 per 100,000 respectively). In 2014, 50% of notifications occurred in males in the 20–39 years age group. Notification rates in males exceeded those in females across all age groups above 20 years (Figure 39). This was consistent with previous years where, with the exception of Indigenous persons, notifications were largely reported in men who have sex with men (MSM).56
From 2009 to 2014, notification rates of gonococcal infection increased annually for males aged 20–39 and 45–49 years. The biggest overall increase was seen in the 45–49 years age group, with notification rates increasing by 171% (from 34.3 to 92.8 per 100,000), followed by the 30–34 years age group, with notification rates increasing by 131% (from 89.0 to 205.6 per 100,000). Compared with males, female rates were lower overall, peaking in 2011–12 in the 15–19 years age group, followed by a decline from 2012 to 2014 (Figure 40).
Indigenous status
The completeness of Indigenous status identification in the notification data varies by year and by jurisdiction. Nationally in 2014, data on Indigenous status were complete for 66% of notifications, which was similar to the preceding 5-year mean of 68% (range: 66% to 72%). All states and territories except New South Wales had greater than 50% completeness of the Indigenous status field across the 2009 to 2014 period. Among the states and territories with greater than 50% completeness, the combined age-standardised notification rate ratio between Indigenous and non-Indigenous populations in 2014 was 26.5:1, increasing from 18.4:1 in 2013. Overall, the rate ratio has declined by 6% from 2009 to 2014 (from 28.1:1 to 26.5:1).
Among the Indigenous population, the age-standardised notification rate decreased by 25% from 2013 to 2014 (from 770.3 to 577.3 per 100,000) and the age-standardised Indigenous rate in 2014 (577.3 per 100,000) was 12% lower than in 2009 (659.7 per 100,000).
Among the non-Indigenous population, the age-standardised notification rate has decreased by 6% from 2009 to 2014 (28.1 and 26.5 per 100,000 respectively).
From 2009 to 2014, notification rates decreased in all states and territories in which Indigenous status was more than 50% complete except Tasmania, (which stabilised following a brief increase, from 4.6 to 4.9 per 100,000) (Figure 41).
Microbiological trends
The AGSP is the national surveillance system for monitoring the antimicrobial resistance of N. gonorrhoeae isolates. These results are published in more detail in the AGSP annual report in CDI.57
In 2014, the AGSP reported that a total of 4,804 gonococcal isolates were referred for antibiotic susceptibility testing, representing 31% of gonococcal infections notified to the NNDSS. This was slightly lower than the proportion of NNDSS cases tested in 2013 (33%, 4,896/14,902).
Eighty-three per cent of the isolates (n=4,009) were from males and 17% (n=791) were from females (M:F, 5.1:1). There were 4 isolates for which gender was unknown. The proportion of gonococcal isolates from males and females tested by the AGSP has remained stable over recent years.
Syphilis (non-congenital categories)
In 2014, 3,930 cases of syphilis (non-congenital categories) were notified to the NNDSS, a rate of 16.8 per 100,000.
Cases of non-congenital syphilis were more frequently reported in MSM.
Syphilis is a sexually transmitted infection caused by the bacterium Treponema palladium. Infection 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.22
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 commenced reporting syphilis of more than 2 years or unknown duration in 2012.
Epidemiological situation in 2014
In 2014, a total of 3,930 cases of syphilis (non-congenital) were reported to the NNDSS. This represented a rate of 16.8 per 100,000, an 11% increase compared with 2013 (15.2 per 100,000) (Figure 42). In 2014, 49% of syphilis notifications were categorised as greater than 2 years or unknown duration, and 51% of cases were categorised as infectious syphilis.
Syphilis – infectious (primary, secondary and early latent), less than 2 years duration
In 2014, 2,009 cases of infectious syphilis were notified to the NNDSS.
Of all notifications, 81% occurred in males aged 20–54 years.
Cases of infectious syphilis were almost completely in MSM.
Epidemiological situation in 2014
In 2014, 2,009 notified cases of infectious syphilis <2 years duration were reported to the NNDSS, representing a rate of 8.6 per 100,000. This was a 13% increase compared with the rate reported in 2013 (7.6 per 100,000) and a 43% increase from 2009 (6.0 per 100,000) to 2014 (Table 6).
Geographical description
In 2014, notification rates for infectious syphilis were highest in the Northern Territory (29.8 per 100,000), Victoria (11.1 per 100,000) and New South Wales (9.8 per 100,000) (Table 16). This likely reflects the large proportions of at-risk individuals living in these jurisdictions; Indigenous persons in the Northern Territory and MSM in Victoria and New South Wales.31,58 Increased screening in at-risk individuals may partly explain increased infection rates; however, the majority of the increase is likely to have been due to increased transmission.59
State or territory | Total* | Male | Female* | |||
---|---|---|---|---|---|---|
Notified cases | Notification rate‡ | Notified cases | Notification rate‡ | Notified cases | Notification rate‡ | |
* Notifications were excluded where the case was aged less than 13 years and the infection was able to be determined as non-sexually acquired (1 notification). † Includes notified cases where sex was not reported. ‡ Per 100,000 population. |
||||||
ACT | 18 | 4.7 | 18 | 9.4 | 0 | 0.0 |
NSW | 739 | 9.8 | 714 | 19.1 | 25 | 0.7 |
NT | 72 | 29.8 | 40 | 30.9 | 32 | 28.6 |
Qld | 394 | 8.3 | 317 | 13.5 | 77 | 3.2 |
SA | 29 | 1.7 | 28 | 3.4 | 1 | 0.1 |
Tas. | 14 | 2.7 | 12 | 4.7 | 2 | 0.8 |
Vic. | 649 | 11.1 | 633 | 21.9 | 16 | 0.5 |
WA | 93 | 3.6 | 82 | 6.3 | 11 | 0.9 |
Total | 2,008 | 8.6 | 1,844 | 15.8 | 165 | 1.4 |
Age and sex distribution
Nationally in 2014, the notification rate for infectious syphilis was 15.8 per 100,000 in males and 1.4 per 100,000 in females, a male to female rate ratio of 11.3:1, which was consistent with previous years. In males, this was an increase of 13% when compared with the 2013 rate (14.0 per 100,000). The notification rate for females in 2014 did not markedly change from the rate seen in 2013 (1.3 per 100,000). In 2014, 81% (1,617/2008) of all notifications occurred in males aged 20–54 years (Figure 43). Similar to that seen in 2013, it is expected that diagnoses of infectious syphilis in 2014 were almost completely confined to MSM.33
Notification rates for males aged 15 years or over varied widely across age groups and increased overall from 2009 to 2014 for all age groups. For the majority of age groups, rates were at their lowest in 2010 after which rates steadily increased and reached maximum values for the period in 2014 (Figure 44).
In females aged 15 years or over, rates did not vary as noticeably across age groups as males (Figure 44). In females, notification rates over the 2009 to 2014 period averaged 2.1 per 100,000 (range: 0.1 to 7.3 per 100,000). Over the 6-year period, the notification rates remained low for females across all age groups.
Indigenous status
The completeness of Indigenous status identification in the notification data varies by year and by jurisdiction. Nationally in 2014, data on Indigenous status were complete for 92% of notifications of infectious syphilis, not changing from 2013, but lower than the preceding 5-year mean of 94% (range: 91% to 96%). All states and territories had greater than 50% completeness of the Indigenous status field across the 2009 to 2014 period.
In 2014, where rates were calculated for Indigenous and non-Indigenous persons, the age-standardised rates were higher for Indigenous persons than non-Indigenous persons in all jurisdictions (Figure 45). For all states and territories, the combined age standardised notification rate ratio between the Indigenous and non-Indigenous populations in 2014 was 4.4:1, which was the same as the preceding 5–year mean (range: 3.0 to 5.9). In 2014, for jurisdictions where cases were notified in both Indigenous and non-Indigenous persons, the age standardised notification rate ratio between Indigenous and non-Indigenous populations ranged from 1.4:1 in New South Wales to 11.6:1 in Queensland. Between 2013 and 2014, the largest increase in the difference between Indigenous and non-Indigenous age standardised notification rates was 318% in the Northern Territory (2.1 to 8.9 per 100,000). The only jurisdiction where the difference between Indigenous and non-Indigenous age standardised notification rates decreased from 2013 to 2014 was South Australia (a decrease of 42%).
An outbreak of infectious syphilis spanning northern areas of Queensland, the Northern Territory, and Western Australia and affecting largely young heterosexual Indigenous persons5,12 was first detected in north-western Queensland in 2012 and in Central Australia in mid-2013,60,61 continuing to 2014. Increased transmission along with targeted and opportunistic syphilis screening in each of these jurisdictions is likely to have contributed to an increase in Indigenous age-standardised rates for Queensland, the Northern Territory, and Western Australia between 2012–2014.61
Syphilis of more than 2 years or unknown duration
In 2014, 1,921 cases of syphilis of more than 2 years or unknown duration were notified to the NNDSS.
Notification rates decreased from 7.3 per 100,000 in 2009 to 6.1 per 100,000 in 2012 then increased to 8.2 per 100,000 in 2014.
The notification rate among males (12.2 per 100,000) was nearly 3 times that in females (4.2 per 100,000) in 2014.
Epidemiological situation in 2014
In 2014, 1,921 cases of syphilis of more than 2 years or unknown duration were reported to the NNDSS. Notification rates increased by 12% between 2009 (7.3 per 100,000) and 2014 (8.2 per 100,000), and increased by 8% between 2013 (7.6 per 100,000) and 2014 (Table 6). This may have been due to increased testing in persons or populations with little previous testing history or it may have been due to an actual increase in the number of persons with non-infectious syphilis.
Geographical distribution
In 2014, notification rates for syphilis of more than 2 years or unknown duration were highest in the Northern Territory (29.8 per 100,000), followed by Victoria (13.7 per 100,000) (Table 17). Similar to infectious syphilis, this geographical distribution likely reflects the large proportions of at-risk individuals living in these jurisdictions (Indigenous persons in the Northern Territory and MSM in Victoria).31,58
State or territory | Total* | Male | Female | |||
---|---|---|---|---|---|---|
Notified cases | Notification rate† | Notified cases | Notification rate† | Notified cases | Notification rate† | |
* Includes notified cases where sex was not reported. † Per 100,000 population. |
||||||
ACT | 26 | 6.7 | 20 | 10.4 | 6 | 3.1 |
NSW | 536 | 7.1 | 411 | 11.0 | 124 | 3.3 |
NT | 73 | 29.8 | 40 | 30.9 | 33 | 28.6 |
Qld | 279 | 5.9 | 182 | 7.7 | 97 | 4.1 |
SA | 123 | 7.3 | 74 | 8.9 | 49 | 5.8 |
Tas. | 19 | 3.7 | 14 | 5.5 | 5 | 1.9 |
Vic. | 801 | 13.7 | 636 | 22.0 | 164 | 5.6 |
WA | 64 | 2.5 | 45 | 3.5 | 19 | 1.5 |
Total | 1,921 | 8.2 | 1,422 | 12.2 | 497 | 4.2 |
Age and sex distribution
Nationally in 2014, the notification rate for syphilis of more than 2 years or unknown duration was 12.2 per 100,000 in males and 4.2 per 100,000 in females, a male to female rate ratio of 2.9:1. Between 2013 and 2014, the notification rate in males increased by 13% (10.8 to 12.2 per 100,000) and by 8% (3.9 to 4.2 per 100,000) in females. In 2014, approximately 73% (1404/1919) of all notifications for which sex was reported, occurred in males aged 20 years or over (Figure 46).
Notification rates in males for all age groups except the 15–19 years age group increased overall from 2009 to 2014 (Figure 47). This increase is particularly prominent from 2012 to 2014. Notification rates in females for all age groups except the 15–19 years age group declined overall from 2009 to 2014 (Figure 47). Notification rates in males in the 15–19 years age group were lower than those of the other age groups and fluctuated across the time period. Notification rates in females in the 15–19 years age group were also lower than those of the other age groups with an increasing trend from 2012 to 2014 (Figure 47).
Congenital syphilis
In 2014, 5 cases of congenital syphilis were notified to the NNDSS.
Congenital syphilis remains rare in Australia.
Congenital syphilis is caused by fetal 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 new-born infant. Congenital syphilis can be asymptomatic, especially in the first weeks of life.22
Epidemiological situation in 2014
There were 5 notifications of congenital syphilis in 2014, all occurring in Indigenous persons. This compared with 7 notifications of congenital syphilis in 2013. The preceding 5-year mean was 4.2 notifications (Table 6). Considering the previously mentioned syphilis outbreak in remote Indigenous communities, the increase in the number of cases seen in 2013 and 2014 (Figure 48) reflects the increased risk to neonates and mothers that outbreak situations pose.62,63 Despite these peaks, case numbers remain low after a downward trend observed over the past decade (Figure 48). Routine antenatal screening for syphilis with follow-up and adequate treatment is considered to be a contributor to this overall decline.64 Congenital syphilis, particularly in Indigenous persons, is targeted for elimination. This target is stated in the 4th National Aboriginal and Torres Strait Islander Blood-borne Viruses and Sexually Transmissible Infections Strategy and the third National Sexually Transmissible Infections Strategy, both for 2014–2017.65,66
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