Sexually Transmitted Infections in New Zealand: Annual Surveillance Report 2014
Friday 24th March 2017
Summary of sexually transmitted infections in New Zealand in 2014
In New Zealand, sexually transmitted infections (STIs) with the exception of AIDS are not notifiable. Surveillance efforts are based on the voluntary provision of data from sexual health clinics (SHCs), family planning clinics (FPCs) and laboratories. Population and disease surveillance therefore varies with the data source.
This report summarises the surveillance information for STIs in 2014 and examines trends over time. The following STIs are reported: chlamydia, gonorrhoea, genital herpes, genital warts, infectious syphilis, non-specific urethritis (NSU), chancroid, granuloma inguinale (GI) and lymphogranuloma venereum (LGV).
With the increasing participation of diagnostic laboratories around New Zealand, laboratory information has become the best indicator of disease incidence for chlamydia and gonorrhoea in most district health boards (DHBs). Laboratories receive specimens from all health providers. In 2014, it was estimated that laboratory surveillance reported approximately two and a half times the number of chlamydia cases and about three times the number of gonorrhoea cases reported by clinic surveillance.
SHCs also provide important information about the epidemiology of STIs. This is because many STIs are diagnosed clinically rather than via laboratory testing (either because laboratory testing is not routinely undertaken for that STI or is insufficient by itself to make the diagnosis). However, the number of cases reported through the clinic-based surveillance system underestimates the true burden of STI disease because a substantial percentage of STIs are diagnosed by other health care providers, particularly primary health care practitioners.
Since 2009, individual DHB and estimated national rates of chlamydia and gonorrhoea have been calculated from laboratory surveillance data. In 2013 and 2014, DHB rates were calculated for all DHBs (except Northland
Chlamydia was the most commonly reported STI in 2014, in both laboratory and clinic settings. A national chlamydia rate (based on all DHBs) of 629 per 100,000 population was calculated from laboratory surveillance data. Eighty-three percent of cases reported through laboratory surveillance data in 2014 were aged between 15 and 29 years. There were 83 cases of chlamydia in infants aged less than one year.
Laboratory surveillance data showed the estimated national rate of chlamydia (based on all DHBs where data was available) was stable between 2009 and 2011 but has decreased since 2012. In those aged between 15 and 29 years, the highest estimated chlamydia rates in 2014 were reported in the Māori and Pacific peoples ethnic groups. Māori females aged 15–19 years reported the highest estimated rate by age group and sex, more than twice the national estimate.
In data derived from SHCs, over 50% of cases were from non-European ethnic groups (Māori, Pacific peoples and Other). In data from laboratories, Tairawhiti, Lakes and Hawke’s Bay DHBs reported the highest chlamydia rates.
In 2014, a national gonorrhoea rate (based on 19 DHBs) of 70 per 100,000 population was estimated from laboratory surveillance data. Seventy-three percent of cases reported by laboratories were aged between 15 and 29 years and one case of gonorrhoea in an infant was reported. Of the 19 DHBs meeting the laboratory selection criteria for analysis in 2014, Tairawhiti reported the highest gonorrhoea rate, over four and a half times the estimated national rate.
In those aged between 15 and 29 years, the highest estimated gonorrhoea rates were reported in the Māori and Pacific peoples ethnic groups. Māori females aged 15–19 years reported the highest estimated rate by age group and sex, more than three times the national estimate.
In SHCs, 58% of cases were from non-European ethnic groups (Māori, Pacific peoples and Other).
The introduction of testing via nucleic acid amplification tests (NAAT) for gonorrhoea since 2011 may have impacted on gonorrhoea case numbers.
The number of cases of syphilis reported by SHCs and FPCs increased notably between 2013 and 2014 (from 85 to 141 cases). The cases were predominantly male (95.7%), MSM, and occurred most commonly in the 20–24 years and 30–34 years age groups. The majority of MSM cases occurred in the NZ European ethnic group (57.0%). Syphilis cases were predominantly reported from clinics in the Auckland region and Canterbury DHB.
From 2013 to 2014, SHCs reported a decrease in case counts of genital warts, genital herpes and NSU (by 4.2%, 2.5% and 2.1%, respectively). The five-year trend from 2010 to 2014 showed a decrease in case counts of genital warts, genital herpes and NSU (by 36.8%, 3.2% and 1.3%, respectively).
One case of lymphogranuloma venereum and no cases of chancroid or granuloma inguinale were reported in 2014.
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