Australia Trachoma Surveillance Report 2011

Discussion

Page last updated: 09 April 2013

Screening coverage

Screening coverage was measured as both the proportion of at-risk communities screened and the proportion of 5-9 year olds 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.

By both screening measures, the screening coverage substantially improved in SA in 2011. Coverage of 5-9 year old children has improved steadily in NT and WA over the past four years, but there was evidence of a slight decline in WA in 2011.

Interpretation of the coverage data is limited by the accuracy of community population estimates and the designation of communities at risk. Community population estimates are based on projections from census data. Although this approach is the most feasible, the estimates may not accurately reflect populations at the time of screening, given the small size and mobility of some communities.

Trachoma prevalence

Endemic trachoma is defined as a prevalence of active trachoma of 5% or greater in children aged 1-9 years. Although the focus of screening was 5-9 year old children, we were able to estimate the prevalence in the larger age band from available data. Across all three jurisdictions in 2011, the prevalence of trachoma in 1-9 year olds was 5%, representing a decrease from the 2010 combined prevalence of 13%. At a regional level, the prevalence of trachoma in 1-9 years ranged from 2% to 28%.

There is strong evidence of a decreasing trend in overall trachoma prevalence in the NT and WA, which is also found when analyses were restricted to the communities that had been screened every year since 2007. Decreasing trends in those two jurisdictions were also observed in the number of communities found to have prevalence above 5% (endemic trachoma) in screened children aged 5-9 years, and there was an increasing trend in the number of communities that reported no trachoma in screened children aged 5-9 years.

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 five years. Several communities designated as at risk have reported prevalences of less than 5% over the past three years, and are therefore on track to be designated not at risk if this status is maintained for two more years.

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 advised. The approach to community-wide treatment differs across jurisdictions. In the NT, the recommendation is taken to mean the entire community, whereas in SA and WA it means all children aged between six months and 14 years.Top of page

Across all three jurisdictions, 65% of those found through screening to have trachoma or to be the household contact of an active case were recorded as having been treated appropriately. Of active cases, 88% received treatment. At the jurisdictional level, 53%, 98% and 85% of the population requiring treatment in NT, SA and WA were treated, respectively. Population estimates are based on projections from ABS census data, which may not accurately represent actual population numbers at time of treatment; however, use of ABS census data is current best practice. Since 2009, the NT has also undertaken six-monthly treatment in hyper endemic communities (>20% prevalence of trachoma). The expansion of this approach in 2010, particularly in the Alice Remote region; may have contributed to the notable decrease in trachoma in that region, from 33% in 2010 to 14% in 2011.

Trichiasis

Coverage of screening for trichiasis among Aboriginal adults aged over 40 years across all jurisdictions remained very low, with screening rates of 3% in the NT, 37% in SA and 6% in WA. Based on these coverage levels, the reporting systems may not provide an accurate estimate of trichiasis prevalence in Aboriginal communities. Furthermore, prevalence rates only include data collected in communities currently designated as communities at-risk trachoma, and do not take into account the possibility that endemic areas have changed over time, so that current at-risk communities may not adequately reflect the place of residence of adults previously exposed to trachoma. Among the limited number of individuals screened, the prevalence of trichiasis in the NT was low.

Referral processes were reported to be functioning within the majority of communities, but the effectiveness of the systems has not been verified. No episodes of trichiasis surgery were reported in 2011, but this may not reflect the true level of ophthalmic consultation and surgical activities occurring.

Facial cleanliness

Facial cleanliness is a major component of the SAFE strategy, recognising that the presence of nasal and ocular discharge is a significant risk factor for both acquiring and transmitting trachoma. The proportion of children screened who had clean faces remained stable in the NT and WA, with prevalences of 77% and 78% screened respectively. In SA, the prevalence of facial cleanliness was recorded at 92% in screened children in 2011.

The status of resources and programs aimed at encouraging facial cleanliness within at-risk communities were not well reported in 2011.

Environment

Data on environmental conditions were not well reported in 2011, with the majority of communities having no relevant data provided. Early in 2012, the Trachoma Surveillance Reference Group (TSRG) decided that the previously used methods of data collection do not accurately capture the environmental conditions recognised to affect trachoma prevalence and transmission. The TSRG and NTSRU are currently collaborating with environmental health agencies to develop more accurate reporting processes for this component of the SAFE strategy.
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Program delivery and monitoring

Despite considerable improvement in several aspects of program delivery and monitoring in 2011, there are several issues that remain to be adequately addressed.

Population denominators: The analyses in this report have used population denominator estimates based on projections from census figures. These estimates are recognised as having the potential for substantial error in communities that are small or show considerable mobility. The problem is not unique to trachoma surveillance and monitoring. While there are alternative denominators that could be considered within specific jurisdictions, they were not available consistently across all locations covered by the trachoma control program. The consequence of erroneous population estimates is a bias in the estimates of screening and treatment coverage rates presented in this report. We have no means for determining the extent or direction of any bias that may be present.

Interpretation of trachoma management guidelines: Through the process of analysing and reporting on the trachoma screening and treatment data, it has become apparent that there are differences across jurisdictions in the interpretation of the 2006 CDNA Guidelines for the Public Health Management of Trachoma in Australia. There is also a need to ensure that the guidelines are up to date. In 2011, the CDNA agreed in to undertake a review of the document, to incorporate the latest information on the screening, treatment and management of trachoma. The document is central to supporting trachoma control programs in the NT, SA and WA, and new programs being established in New South Wales and Queensland.

The Trachoma Framework Review Working Group, acting as a CDNA subcommittee, will guide the review process, and the NTSRU will manage the review process.

Data quality: For the 2011 report, as with previous reports, there were issues of data quality in all jurisdictions, including missing or inconsistent entries. During 2011 the NTSRU developed a web-based interface program to increase the likelihood of consistent reporting across jurisdictions and regions through the use of a standard, simple to use data entry system. The system also allows for more efficient data validation and reporting to stakeholders, including communities. It is anticipated that it will be fully operational in the course of 2012.

Progress towards Australia's elimination target

As a signatory to the WHO Alliance of Global Elimination of Trachoma by the year 2020, Australia is committing to ensuring that trachoma levels continue to fall to below-endemic levels in at-risk communities.

This report shows strong evidence of increasing coverage of trachoma screening and control activities. In NT and WA, there is also evidence of a decline in the prevalence of infection that may be attributable to improvement in control activities. Despite these apparent advances, trachoma prevalence remains at endemic levels in many communities of remote Australia. Continued efforts are required to ensure that Australia remains on track to reach the goal of elimination by 2020 or earlier.