Prevalence of Trachoma at Sub-District Level in Ethiopia: Determining When to Stop Mass Azithromycin Distribution

Abstract

BackgroundTo eliminate blinding trachoma, the World Health Organization emphasizes implementing the SAFE strategy, which includes annual mass drug administration (MDA) with azithromycin to the whole population of endemic districts. Prevalence surveys to assess impact at the district level are recommended after at least 3 years of intervention. The decision to stop MDA is based on a prevalence of trachomatous inflammation follicular (TF) among children aged 1–9 years below 5% at the sub-district level, as determined by an additional round of surveys limited within districts where TF prevalence is below 10%. We conducted impact surveys powered to estimate prevalence simultaneously at the sub-district and district in two zones of Amhara, Ethiopia to determine whether MDA could be stopped.MethodologySeventy-two separate population-based, sub-district surveys were conducted in 25 districts. In each survey all residents from 10 randomly selected clusters were screened for clinical signs of trachoma. Data were weighted according to selection probabilities and adjusted for correlation due to clustering.Principal FindingsOverall, 89,735 residents were registered from 21,327 households of whom 72,452 people (80.7%) were examined. The prevalence of TF in children aged 1–9 years was below 5% in six sub-districts and two districts. Sub-district level prevalence of TF in children aged 1–9 years ranged from 0.9–76.9% and district-level from 0.9–67.0%. In only one district was the prevalence of trichiasis below 0.1%.Conclusions/SignificanceThe experience from these zones in Ethiopia demonstrates that impact assessments designed to give a prevalence estimate of TF at sub-district level are possible, although the scale of the work was challenging. Given the assessed district-level prevalence of TF, sub-district-level surveys would have been warranted in only five districts. Interpretation was not as simple as stopping MDA in sub-districts below 5% given programmatic challenges of exempting sub-districts from a highly regarded program and the proximity of hyper-endemic sub-districts.

Prevalence of Active Trachoma and Associated Factors in Areka Town, South Ethiopia, 2018

“…The difference might be due to the difference in sample size and study population. However, it was higher than other related studies conducted in different parts of Ethiopia: Baso Liben District (24.1%) [ 14 ], Oromia Region (23.4%) [ 13 ], Amhara (21.6%) [ 5 ], Somali (22.6%), SNNPR (33.2%), Tigray (26.5%), and Gambella (19.1%) [ 7 ], and Dera Woreda (15.6%) [ 15 ], Dembia District (18%) [ 3 ], South Wollo (26.4%) [ 16 ], and Harari Regional State (1.3%) [ 17 ]. It was also higher than related studies from Senegal (2.5%) [ 8 ], Nigeria (0.04–19%) [ 18 ], Kenya (18.7%) [ 2 ], and Burkina Faso (9.5%) [ 19 ].…”

Coverage, social mobilization and challenges of mass Zithromax administration campaign in South and South East zones of Tigray, Northern Ethiopia: A cross sectional study

“…It blinds one person every 15 minutes and makes one person experience severe sight loss every four minutes. Fifty three countries are estimated to be endemic for blinding trachoma and around 200 million people live in those areas [ 2 , 3 ].…”

“…Trachoma control program implementation is prioritized in communities where prevalence of active trachoma in children aged 1 to 9 years is 10% or higher and/or where the prevalence of TT in people aged 15 or above is one percent or higher. One round treatment is also recommended in areas between 5% - 9.9% infection in children aged under 10 years [ 3 , 7 – 8 ].…”

Genomics of OcularChlamydia trachomatisafter 5 years of SAFE interventions for trachoma in Amhara, Ethiopia

“…Sampling methodology for these district-level surveys has been published previously. 3,24 Briefly, a multi-stage cluster randomized methodology was used, whereby clusters (villages) were selected using a population proportional to estimated size method, and within a cluster, a modified segmentation approach was used to randomly select segments of 30 to 40 households. 3 After enumerating all residents, present and consented residents were examined for trachoma based on the WHO simplified methodology.…”