Role of flies and provision of latrines in trachoma control: cluster-randomised controlled trial

Abstract. We assessed trachoma grading agreement among field graders using photographs that included the complete spectrum of disease and compared it with cases where there was consensus among experienced graders. Trained photographers took photographs of children's conjunctiva during a clinical trial in Ethiopia. We calculated κ-agreement statistics using a complete set of 60 cases and then recalculated the κ using a consensus set where cases were limited to those cases with agreement among experienced graders. When the complete set of 60 cases was used, agreement was moderate (κ = 0.61, 95% confidence interval [95% CI] = 0.56-0.67). When the consensus set was used, agreement improved significantly (κ = 0.75, 95% CI = 0.68-0.80). The κ of the consensus set was higher than the complete set by 0.14 (95% CI = 0.12-0.16) (P 0.001). If testing sets remove difficult-to-grade cases, agreement in trachoma grading may be higher than actually seen in population-based trachoma surveys.

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“…4,6,13,[20][21][22] Photo grading has advantages over field grading. (1) Exam conditions can be standardized.…”

Section: Discussionmentioning

confidence: 99%

“…2,3 Individual-and community-randomized clinical trials have typically had clinical exam as primary or secondary outcomes. [4][5][6][7][8][9] Unfortunately, grading of clinical trachoma can have considerable variability. Even with rigorous training, different examiners grade cases differently.…”

Section: Introductionmentioning

confidence: 99%

Importance of Including Borderline Cases in Trachoma Grader Certification

Gaynor

Amza

Gebresailassie

et al. 2014

The American Society of Tropical Medicine and Hygiene

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“…2 Transmission of the causative agent, ocular strains of Chlamydia trachomatis , occurs from eye to eye via hands, clothing and bedding, or via mechanical transmission by eye-seeking flies. 3–5 …”

Section: Introductionmentioning

confidence: 99%

Prevalence of and Risk Factors for Trachoma in Southern Nations, Nationalities, and Peoples’ Region, Ethiopia: Results of 40 Population-Based Prevalence Surveys Carried Out with the Global Trachoma Mapping Project

Adera

Macleod

Endriyas

et al. 2016

Ophthalmic Epidemiology

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Purpose: We sought to estimate the prevalence of trachoma at sufficiently fine resolution to allow elimination interventions to begin, where required, in the Southern Nations, Nationalities, and Peoples’ Region (SNNPR) of Ethiopia. Methods: We carried out cross-sectional population-based surveys in 14 rural zones. A 2-stage cluster randomized sampling technique was used. A total of 40 evaluation units (EUs) covering 110 districts (“woredas”) were surveyed from February 2013 to May 2014 as part of the Global Trachoma Mapping Project (GTMP), using the standardized GTMP training package and methodology. Results: A total of 30,187 households were visited in 1047 kebeles (clusters). A total of 131,926 people were enumerated, with 121,397 (92.0%) consenting to examination. Of these, 65,903 (54.3%) were female. In 38 EUs (108 woredas), TF prevalence was above the 10% threshold at which the World Health Organization recommends mass drug administration with azithromycin annually for at least 3 years. The region-level age- and sex-adjusted trichiasis prevalence was 1.5%, with the highest prevalence of 6.1% found in Cheha woreda in Gurage zone. The region-level age-adjusted TF prevalence was 25.9%. The highest TF prevalence found was 48.5% in Amaro and Burji woredas. In children aged 1–9 years, TF was associated with being a younger child, living at an altitude <2500m, living in an area where the annual mean temperature was >15°C, and the use of open defecation by household members. Conclusion: Active trachoma and trichiasis are significant public health problems in SNNPR, requiring full implementation of the SAFE strategy (surgery, antibiotics, facial cleanliness, and environmental improvement).

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“…Successful reductions in trachoma caused by Chlamydia trachomatis have recently been achieved in the Gambia by reducing the density of the filth fly Musca sorbens (Wiedemann), which constitutes an important arthropod vector along with the house fly Musca domestica in Africa 1,2,3 , and the bush fly Musca vetustissima (Walker) in Australia 4 .…”

Section: Introductionmentioning

confidence: 99%