News Release 

New research discovers the financial cost of trachoma surveys

Impact surveys critical to tracking bacterial disease that causes blindness



IMAGE: Bijaya Paudel, Trachoma Grader, checks the eye of Maiya Dani for clinical signs of trachoma. view more 

Credit: Source: RTI International/Nabin Baral, A Last Check for Trachoma in Nepal (CC BY 2.0)

The global health community is working to eliminate trachoma, a bacterial disease that causes blindness. Researchers reporting in PLOS Neglected Tropical Diseases have analyzed the costs of surveys that must track trachoma levels as part of these elimination efforts.

In the new work, Rachel Stelmach of RTI International, USA, and colleagues studied the financial costs to the national program of TSS and TIS in 11 countries from 2012 to 2018. Cost data was available for surveys supported by the ENVISION project funded by the US Agency for International Development (USAID) and led by RTI International. Financial costs of TT-only surveys in Cameroon, Tanzania, Uganda and Nepal were also included. Only incremental costs were studied-- costs that would have been incurred to the national program anyway were not included, nor were economic costs or costs to society such as the value of subjects' time.

The researchers were able to gather data on 228 TIS and 94 TSS, or 322 surveys in total. The surveys cost a median of $8,298 USD (IQR: $6,532 - $10,111) and did not differ significantly by survey type, data source, or years of implementation, though the authors found evidence of economies of scale from implementing surveys in a single year. Survey fieldwork accounted for a majority (80%) of costs, with training accounting for the next largest proportion of costs (13%). TT-only surveys appeared to cost about the same or slightly more than TIS and TSS in the same country. Cost differences between countries were mostly driven by how much it costs to pay surveyors and transport them to survey sites.

The World Health Organization requires that countries conduct trachoma impact surveys (TIS) to see whether a district has reached prevalence benchmarks that allow them to stop population-level prevention interventions, as well as trachoma surveillance surveys (TSS) to later ensure that trachoma has remained at bay.

"Costing studies like this one provide crucial planning data as countries advance toward the elimination of trachoma as a public health problem," the researchers say.

A trachomatous trachoma only (TT-only) survey, measuring one classification of the disease only, is also used in some contexts. Estimates of the costs of baseline trachoma prevalence surveys exist, but the costs of additional later surveys had not previously been studied.


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Citation: Stelmach RD, Flueckiger RM, Shutt J, Davide-Smith M, Solomon AW, et al. (2019) The costs of monitoring trachoma elimination: Impact, surveillance, and trachomatous trichiasis (TT)-only surveys. PLOS Neglected Tropical Diseases 13(9): e0007605.

Funding: RDS received the following specific funding for this work: This study was made possible thanks to funding from ENVISION, a global project led by RTI International in partnership with CBM International, The Carter Center, Fred Hollows Foundation, Helen Keller International, IMA World Health, Light for the World, Sightsavers, and World Vision. ENVISION is funded by the US Agency for International Development under cooperative agreement No. AID-OAA-A-11-00048. The period of performance for ENVISION is September 30, 2011 through September 30, 2019. For more information, go to

The authors alone are responsible for the views expressed in this article, which do not necessarily represent the views, decisions, or policies of the institutions with which the authors are affiliated, the United States Agency for International Development, or the United States Government.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

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