The Global Trachoma Mapping Project: methodology of a 34-country population-based study

Summary

This paper describes the purpose and methodology of the Global Trachoma Mapping project (GTMP). The GTMP was set up to complete the baseline trachoma map worldwide by conducting population-based surveys in an estimated 1,238 suspected endemic districts of 34 countries.

Under GTMP methodology house-to-house cluster random sample surveys are conducted in evaluation units, which generally correspond to health district size populations of 100,000-250,000 people. In addition to individual-level demographic and clinical data, household-level water, sanitation and hygiene data are entered into the purpose-built LINKS application on Android smartphones, transmitted to the Cloud, and cleaned, analysed and ministry-of-health-approved via a secure web-based portal.

The main outcome measures are the evaluation unit-level prevalence of follicular trachoma in children aged 1-9 years, prevalence of trachomatous trichiasis in adults aged 15+ years, percentage of households using safe methods for disposal of human faeces, and percentage of households with proximate access to water for personal hygiene purposes.