Quality Assurance and Quality Control in the Global Trachoma Mapping Project

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Purpose: A number of previous administrative-district-level baseline trachoma prevalence estimates in Zambia required verification. We used methodologies and systems for trachoma surveys considered to represent international best practice in order to generate reliable estimates of the prevalence of trachoma. Methods: Between March 2016 and July 2017, we undertook 32 population-based prevalence surveys covering 47 administrative districts. In each of the 32 evaluation units (EUs), we selected 31 households in each of 24 clusters. In selected households, trained, certified graders examined all residents aged 1 year and above for evidence of trachomatous inflammation-follicular (TF) and trichiasis. In eyes that had trichiasis, the presence or absence of trachomatous scarring (TS) was recorded, and the subject was asked about previous trichiasis management recommendations from health workers. Results: Five EUs (encompassing seven administrative districts) had prevalence estimates of trichiasis+TS unknown to the health system in ≥15-year-olds of ≥0.2%, and require publichealth-level implementation of trichiasis surgery services. Eleven EUs (encompassing 16 administrative districts) had TF prevalence estimates in 1-9-year-olds of ≥5%. Intervention with the A, F and E components of the SAFE strategy for trachoma elimination is required for nearly 1.5 million people. Conclusion: Trachoma is a public health problem in some parts of Zambia. The Ministry of Health will continue to partner with other stakeholders to implement the multi-sectoral SAFE strategy. Consideration should be given to re-surveying other suspected-endemic administrative districts in which surveys using older methodologies returned TF prevalence estimates ≥5%.

Section: Methodssupporting

confidence: 68%

Section: Discussionmentioning

confidence: 83%

Prevalence of Trachoma in 47 Administrative Districts of Zambia: Results of 32 Population-Based Prevalence Surveys

Mwale¹,

Mumbi

Funjika

et al. 2018

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“…Standard GTMP approaches 28,29 were used for data cleaning, analysis, health ministry review, and approval. In the first 23 completed EUs, lacking information on the presence or absence of TS in eyes with trichiasis, we calculated the prevalence of "any trichiasis"; for the last 19 completed EUs, we calculated the prevalence of both any trichiasis and "trichiasis+TS", defined here as the presence of both trichiasis and TS (or the inability of the examiner to evert the lid to look for TS, presumed to be due to dense scarring) in the same eye.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Trachoma in Pakistan: Results of 42 Population-Based Prevalence Surveys from the Global Trachoma Mapping Project

Khan

Florea

Hussain

et al. 2020

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Purpose: Previous phases of trachoma mapping in Pakistan completed baseline surveys in 38 districts. To help guide national trachoma elimination planning, we set out to estimate trachoma prevalence in 43 suspected-endemic evaluation units (EUs) of 15 further districts. Methods: We planned a population-based trachoma prevalence survey in each EU. Two-stage cluster sampling was employed, using the systems and approaches of the Global Trachoma Mapping Project. In each EU, residents aged ≥1 year living in 30 households in each of 26 villages were invited to be examined by trained, certified trachoma graders. Questionnaires and direct observation were used to evaluate household-level access to water and sanitation. Results: One EU was not completed due to insecurity. Of the remaining 42, three EUs had trichiasis prevalence estimates in ≥15-year-olds ≥0.2%, and six (different) EUs had prevalence estimates of trachomatous inflammation-follicular (TF) in 1-9-year-olds ≥5%; each EU requires trichiasis and TF prevalence estimates below these thresholds to achieve elimination of trachoma as a public health problem. All six EUs with TF prevalences ≥5% were in Khyber Pakhtunkhwa Province. Household-level access to improved sanitation ranged by EU from 6% to 100%. Household-level access to an improved source of water for face and hand washing ranged by EU from 37% to 100%. Conclusion: Trachoma was a public health problem in 21% (9/42) of the EUs. Because the current outbreak of extremely drug-resistant typhoid in Pakistan limits domestic use of azithromycin mass drug administration, other interventions against active trachoma should be considered here. ARTICLE HISTORY

“…Completion of the survey was a credit to the field teams, who negotiated the terrain without complaint and returned data of high quality. 28,37 There was, however, one particular shortcoming in our survey. Because of access issues and the spatial distribution of households, as noted in the Methods section above, it was not possible to include 30 households in each village.…”

Section: Discussionmentioning

confidence: 96%

“…In this study, we employed the momentum, 18,27 systems 19,28 and funding 29 of the GTMP to investigate whether trachoma was a public health problem in an area felt to be the most at-risk part of the Republic of the Congo, a hitherto-unsurveyed country. This survey was set up as the epidemiological equivalent of a canary in the mine, with the understanding that finding trachoma at levels indicative of a public health problem here would prompt further trachoma surveys in surrounding health districts, 3,4 and potentially further afield.…”

Section: Discussionmentioning

confidence: 99%

A Population-Based Trachoma Prevalence Survey Covering Seven Districts of Sangha and Likouala Departments, Republic of the Congo

Missamou

Marlhand

Dzabatou-Babeaux

et al. 2018

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Purpose : We set out to estimate the prevalence of trachoma and access to water and sanitation in seven suspected-trachoma-endemic districts of northern Congo, surveyed as a single evaluation unit. Methods : From a complete list of rural villages in the seven districts, we systematically selected 22 with probability proportional to village size. In selected villages, we included all households where there were fewer than 25 in total, or used compact segment sampling to select a group of approximately 20 households by random draw. In each selected household, all consenting residents aged ≥1 year were examined by Global Trachoma Mapping Project-certified trachoma graders, and data collected on household-level access to water and sanitation. Results : In November and December 2015, 466 households were visited in 22 villages, and 2081 (88%) of 2377 residents of those households were examined. No examined individual had trichiasis. The age-adjusted prevalence of the active trachoma sign trachomatous inflammation—follicular (TF) in 1–9-year-olds was 2.5% (95%CI 0.9–4.5%). Only 39% (95%CI 35–44%) of households had access to an improved source of drinking water. Only 10% (95%CI 7–13%) of households had access to an improved sanitation facility. Conclusion : Trachoma is not a public health problem in this part of Congo. Access to water and sanitation is inadequate.