Control of Trachoma in Australia: A Model Based Evaluation of Current Interventions

Abstract

BackgroundAustralia 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 FindingsA 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/SignificanceMaintaining 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.

Molecular characteristics of the ompA gene of serotype B Chlamydia trachomatis in Qinghai Tibetan primary school students

“…Trachoma is closely associated with serotypes A, B, Ba, and C (Last et al, 2014;Ishak et al, 2015). C. trachomatis remains an epidemic in various countries, and Canada is the only high-income country with a trachoma prevalence of >5% (Shattock et al, 2015). Active trachoma exists in a number of areas in Asia and Africa and other developing countries (Last et al, 2014;King et al, 2013;Nigusie et al, 2015;Burton et al, 2010), and a great number of studies have shown C. trachomatis serotypes differ across regions.…”

Mass drug administration: the importance of synchrony

“…More comprehensive studies should consider the influence of partial acquired immunity (Liu et al ., 2013), chemoprophylaxis in susceptible persons, seasonality in transmission (Lee et al ., 2005), age-structure in the host population (Bailey et al ., 1999; Lietman et al ., 1999; Gambhir et al ., 2009), bacterial load (Shattock et al ., 2015), case importation, and other ecological or epidemiological factors (Lietman et al ., 1999). Changes in population size, structure and distribution need to be reflected in a long-term MDA program.…”

Improving our forecasts for trachoma elimination: What else do we need to know?

“…We evaluate 4 different plausible natural histories of infection [ 9 , 11 , 13 , 26 ] and disease [ 7 , 16 , 18 , 19 ] that may occur following exposure to trachoma. The model structures we evaluate highlight the clinical and epidemiological observations made in the field and laboratory [ 19 , 21 , 27 , 28 ].…”

“…In addition to the SIS compartmental model structure, several other variant structures may also be considered appropriate given the natural history of trachoma infection [ 18 – 21 ]. It has been reported for other infectious diseases that the structure of the model assumed can impact the estimated effort required to control and eliminate that disease [ 22 – 24 ].…”