Australian Trachoma Surveillance Report 2012

Discussion

Trachoma screening and management data for 2012 were provided to the National Trachoma Surveillance and Reporting Unit by the Northern Territory (NT), South Australia (SA), Western Australia (WA) and Queensland (Qld). Data were analysed by region in the NT, SA and WA, with five regions in the NT, four in SA and four in WA. Queensland screened six communities and its data was aggregated for analysis. Jurisdictional authorities had designated 204 remote Aboriginal communities as being at risk of endemic trachoma in 2012.

Page last updated: 23 December 2013

Screening coverage

Screening coverage was measured as both the proportion of at-risk communities screened and the proportion of 5-9 year-old children screened in at-risk communities, predominantly through primary school-based initiatives. Screening of older (10-14-year-old) and younger (1-4-year-old) children also takes place, but less consistently, and in 2012 many regions chose to focus screening exercises solely on the 5-9-year age group. In 2012 population estimates provided by jurisdictions were used to calculate proportions. The manner in which the populations were calculated differed among jurisdictions, with some jurisdictions using school enrolment lists, Health Information populations lists, or a combination of both and local knowledge. The 2011 Australian Bureau of Statistics (ABS) census projected population estimates were included in the tables to provide a comparison. Population estimates were generally similar for the 5-9-year age group except in Qld. In 2012 all regions, increased trachoma screening coverage of 5-9-year-old children except Darwin Rural region in the NT and Far North region in SA, compared to 2011 data. A higher screening coverage provides confidence that those screened are representative of the community at risk, and results are therefore an accurate reflection of the prevalence of disease within the community.

The number of at-risk communities screened has increased in the NT, SA and WA. It is expected, however, that this will plateau and in some regions decrease in future years. A number of communities screened for the first time in 2012 did not have trachoma, and therefore do not qualify as being at-risk for future years.

The Guidelines for the public health management of trachoma in Australia is currently undergoing review. The new guidelines will allow hyperendemic communities to focus resources on treatment without the need for repeat screening for up to 3 years. If endorsed, this strategy will affect the number of communities screened and the regional screening coverage of children. The impact of this strategy may not be apparent for several years.

Trachoma prevalence

Endemic trachoma is defined by WHO as a prevalence of active trachoma of 5% or more in children aged 1-9 years. In past years the National Trachoma Surveillance and Reporting Unit (NTSRU) has been able to estimate the prevalence using population weights. Due to the poor screening coverage of the 1-4-year age group, it was considered that the results reported were not representative of that age group. In Australia, the prevalence in the 5-9-year age group is accepted as a sufficient measure of the prevalence of trachoma within at-risk communities.

Across all four jurisdictions in 2012, the prevalence of trachoma in 5-9-year-old children was 4%. This is a decrease from the 2011 national prevalence of trachoma in 5-9-yearold children of 7%.9 At a regional level in 2012, the prevalence of trachoma in children aged 5-9 years ranged from 0% to 4%.

Queensland detected no trachoma in any of the six communities screened. Follicles consistent with Trachomatous inflammation – follicular were observed in one community, however PCR tests results taken from children with follicles and their household contacts were negative for Chlamydia trachomatis. Subsequently, Queensland has concluded that trachoma is not a public health concern for Queensland.

In all other jurisdictions screened, a decreasing trend in trachoma prevalence is observed since 2009. Decreasing trends in the NT, SA and WA were also observed in the number of communities found to have a prevalence greater than 5% (endemic trachoma) in screened children aged 5-9 years, and there was an increasing trend in the number of communitiesthat reported no trachoma in screened children aged 5-9 years It may be timely to review the risk classifications of communities that reported no evidence of trachoma, presently or historically, such as three in the Darwin Rural region, four in the Katherine region (NT); one in Eyre and Western region, seven in the Far North region, all of the York and Mid North region (SA); two in the Goldfields region, two in the Midwest region and three in the Kimberley region (WA).

The target set by both WHO and CDNA for elimination of blinding trachoma is community prevalence in children aged 1-9 years of less than 5% over a period of 5 years. Several communities designated as at-risk have reported a prevalence of less than 5% over the past 4 years, and are therefore on track to be designated not at-risk if this status is maintained for one more year.

As these communities are reclassified as being not at-risk, future prevalence trends may increase for a period of time as the at-risk population becomes more concentrated.

In 2012 the NTSRU collected prevalence data by sex. These data had not been collected in previous years. There is evidence in many trachoma endemic countries that women are disproportionately more likely to be at risk of trachoma, and become blind due to trichiasis.16 However, the national results from 2012 illustrate that males in all endemic Australian jurisdictions had a higher prevalence of trachoma compared to females.

Trachoma treatment

CDNA guidelines recommend the treatment of active cases and their household contacts. When prevalence is greater than 10% and cases are not clustered within a few households, community-wide treatment is suggested. The approach to community-wide treatment differs across jurisdictions. In the NT, the recommendation is taken to mean the entire community, whereas SA and WA choose to treat all children aged between 6 months and 14 years. The differences in approach are a response to the average number of contacts per active case in each jurisdiction: in the NT 1:24, 1:7 in SA and 1:6 in WA.

Ninety-five percent of active cases received treatment.

In 2012 jurisdictions supplied estimates of the populations requiring treatment. These estimates were influenced by the interpretation of the current treatment guidelines. For six communities in WA in which only active cases were treated, estimates of the number of household contacts or community members requiring treatment were not obtained; therefore treatment coverage was overestimated for WA. Nationwide, 75 of the 87 communities that required treatment were treated according to their jurisdictional interpretation of the current CDNA treatment guidelines.

The NT also undertook 6-monthly treatment of all members of the community in six communities that detected hyperendemic levels of trachoma and achieved an overall coverage level of 70% for the second treatment.

Trichiasis

Coverage of screening for trichiasis among Aboriginal adults aged over 40 years in the NT, SA and WA increased in 2012; however coverage remained low, with screening rates of 18% in the NT, 47% in SA and 52% in WA. Of the adults screened in communities designated as at risk for trachoma, 2% (94/4,468) prevalence levels include only data collected in communities currently designated “at-risk”, and do not take into account the possibility that endemic areas may have changed over time.

In 2012, sixteen cases of trichiasis surgery were reported in NT (5), SA (2) and WA (9).

Facial cleanliness

Facial cleanliness is a major component of the SAFE strategy, recognising that the presence of nasal and ocular discharge significantly correlates to the risk for both acquiring and transmitting trachoma. The proportion of 5-9-year-old children screened who had clean faces increased slightly in all jurisdictions compared to 2011. WHO has set targets for communities to reach a rate of 80% facial cleanliness.17 This target was achieved by 58% of all screened communities nationally.

Program delivery and monitoring

Significant improvements in program delivery have been reported in 2012 with increased coverage of screening and treatment delivery and health promotion activities. Data quality also improved in all jurisdictions; however, as many regions chose to focus on the 5-9-year age group, data regarding the 1-4-year age group were not comprehensive. The NTSRU in 2011 developed a web-based data entry system that minimised duplicates and inconsistent entry. This database is being enhanced to allow improved accessibility in the field and report generation for jurisdictions.

In 2011, CDNA initiated a review of the 2006 CDNA Guidelines for the public health management of trachoma in Australia.The revised guidelines are expected to be endorsed by CDNA in 2013. This revised document aims to reduce the ambiguity and provide clear guidance on screening and treatment methods.

Progress towards Australia’s elimination target

As a signatory to the WHO Alliance of the Global Elimination of Blinding Trachoma by the year 2020 (GET 2020), Australia is committed to ensuring that trachoma levels continue to decrease to below endemic levels in at-risk communities. This report has shown significant decreases in trachoma prevalence in NT, SA and WA. With the implementation of new guidelines in 2013 and sustained efforts, as reported in 2012, Australia remains on course to eliminate trachoma by 2020.