Impact
Since 2006, RTI has led NTD programs and worked with partners to reach over 65 countries with training, technical support, and resources to improve the impact and effectiveness of NTD services. In 2018, RTI committed $3 million of its own funding to accelerate research and develop innovations to eliminate NTDs.
Spatial Analysis and Modeling to Support Trachoma Elimination
Trachoma is a preventable disease that causes suffering and blindness, particularly in more vulnerable populations. It results from repeated infections that scar the inner eyelid, causing eyelashes to turn inward and scratch the eye. Without treatment, this leads to irreversible blindness.
Using existing data from trachoma surveillance surveys, we developed innovative spatial methods for creating trachoma risk maps that show areas of ongoing transmission prior to elimination and areas at risk of recurrence after elimination.
This activity aimed to measure spatial clustering in the distribution of trachomatous inflammation—follicular (TF) among clusters and determine if there is a relationship between TF prevalence in clusters and available measures of local environmental and sociodemographic conditions. The findings showed how trachoma data can be used in more complex geostatistical models and have been published and shared at several international conferences.
This work has also contributed to larger discussions within the World Health Organization and global partners on the use of model-based geostatistics for estimating trachoma elimination.
Test Alternative Survey Strategies to Find and Control Trachoma
To better understand and identify causes of persistent and recurrent active trachoma, in collaboration with the University of California San Francisco and the U.S. Centers for Disease Control and Prevention, we researched the effectiveness of alternative treatment and surveillance strategies, including adding the collection of eye swabs and dried blood samples to standard trachoma surveys.
In Mozambique, to characterize transmission in four districts, we incorporated testing of ocular infection and serology into routine trachoma impact surveys in August 2022. We found that three recurrent districts had prevalence of trachomatous inflammation—follicular (TF) below the 5% threshold for discontinuation of antibiotic mass drug administration (MDA), while the remaining district had a TF prevalence at least 5%, confirming it as a district with persistent active trachoma.
This was the first time globally that this type of information was incorporated into trachoma surveys and proved the feasibility of such enhanced surveys. By measuring additional biomarkers, we learned that in two of the districts with TF prevalence below 5% the observed prevalence of ocular Chlamydia trachomatis infection and seroconversion rates suggest transmission of trachoma was ongoing. Close follow-up and resumption of MDA may be required in the future. Analysis of household water and sanitation data furthered our understanding of likely drivers of ongoing trachoma transmission in this setting, including lack of access to sanitation and low sanitation coverage.
