Control of trachoma in Australia: a model based evaluation of current interventions

Background 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 5–9 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%). Conclusions/Significance 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.
Author Summary 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.