Control of Trachoma in Australia: A Model Based Evaluation of Current Interventions
April
Control of Trachoma in Australia: A Model Based Evaluation of Current Interventions
Andrew J. Shattock 0 1
Manoj Gambhir 0 1
Hugh R. Taylor 0 1
Carleigh S. Cowling 0 1
John M. Kaldor 0 1
David P. Wilson 0 1
0 1 The Kirby Institute, University of New South Wales , Sydney , Australia , 2 Department of Epidemiology and Preventive Medicine, Monash University , Melbourne , Australia , 3 Melbourne School of Population Health, The University of Melbourne , Melbourne , Australia
1 Editor: Jeremiah M. Ngondi, University of Cambridge, UNITED KINGDOM
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Funding: This study was funded by the Australian
Government Department of Health and Ageing with
the intention of using the work to inform best practice
towards elimination by 2020. Representatives from
the Australian Government reviewed the manuscript
and provided comments for consideration. The study
was also supported by the Australian Research
Council and the National Health and Medical
Research Council. The Kirby Institute is funded by
the Australian Government, Department of Health
and Ageing. The views expressed in this publication
do not necessarily represent the position of the
Australia is the only high-income country in which endemic trachoma persists. In response,
the Australian Government has recently invested heavily towards the nationwide control of
the disease.
Methodology/Principal Findings
A novel simulation model was developed to reflect the trachoma epidemic in Australian
Aboriginal communities. The model, which incorporates demographic, migration, mixing, and
biological heterogeneities, was used to evaluate recent intervention measures against
counterfactual past scenarios, and also to assess the potential impact of a series of
hypothesized future intervention measures relative to the current national strategy and intensity.
The model simulations indicate that, under the current intervention strategy and intensity,
the likelihood of controlling trachoma to less than 5% prevalence among 59 year-old
children in hyperendemic communities by 2020 is 31% (19%43%). By shifting intervention
priorities such that large increases in the facial cleanliness of children are observed, this
likelihood of controlling trachoma in hyperendemic communities is increased to 64% (53%
76%). The most effective intervention strategy incorporated large-scale antibiotic
distribution programs whilst attaining ambitious yet feasible screening, treatment, facial cleanliness
and housing construction targets. Accordingly, the estimated likelihood of controlling
trachoma in these communities is increased to 86% (76%95%).
Maintaining the current intervention strategy and intensity is unlikely to be sufficient to
control trachoma across Australia by 2020. However, by shifting the intervention strategy and
increasing intensity, the likelihood of controlling trachoma nationwide can be significantly
increased.
Australian Government. The Kirby Institute is affiliated
with the University of New South Wales.
Competing Interests: The authors have declared
that no competing interests exist.
Australia is the only remaining high-income country reporting endemic levels of
trachoma, with infections occurring predominantly within rural and remote Indigenous
communities. Although the Australian government has recently invested large sums of money to
combat the disease, it remains unclear whether the national goal of controlling trachoma
by 2020 will be achieved. Here, we use a novel individual-based simulation model to
estimate the impact of numerous potential future invention strategies and intensities. Our
model is the most sophisticated trachoma transmission model to date, and the first to
specifically represent trachoma in Australian Indigenous communities. Model projections
suggest that although the current intervention strategy and intensity are unlikely to
achieve the target of national control by 2020, the likelihood of achieving this goal can be
significantly increased by shifting the intervention strategy and increasing the intensity of
key intervention components such as screening, treatment and facial cleanliness activities.
Our findings that the most resource rich country with endemic trachoma may require a
more intensive intervention effort to control the disease suggest that challenges may
remain in the fight for the global control and eventual elimination and eradication
of trachoma.
Australia is the only high-income country in which trachoma, the worldwide leading cause of
preventable blindness [1], remains endemic [2]. In remote Aboriginal communities deemed to
be at-risk of trachoma, an estimated 4% of adults suffer severely impaired vision or blindness
[3] due to many years of repeated re-infection with the bacterium Chlamydia trachomatisthe
infectious agent from which trachoma disease develops [4]. In 2009, the Australian
government pledged AUS$16 million over an initial four-year period towards the national goal of
controlling trachoma by 2020 [3]. That is, to (...truncated)