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. 2021 May 13;21(1):213.
doi: 10.1186/s12886-021-01972-w.

The population-based prevalence of trachomatous scarring in a trachoma hyperendemic setting: results from 152 impact surveys in Amhara, Ethiopia

Tigist Astale  1 , Caleb D Ebert  2 , Andrew W Nute  3 , Mulat Zerihun  1 , Demelash Gessese  1 , Berhanu Melak  1 , Eshetu Sata  1 , Zebene Ayele  1 , Gedefaw Ayenew  1 , E Kelly Callahan  3 , Mahteme Haile  4 , Taye Zeru  4 , Zerihun Tadesse  1 , Scott D Nash  3
Affiliations

The population-based prevalence of trachomatous scarring in a trachoma hyperendemic setting: results from 152 impact surveys in Amhara, Ethiopia

Tigist Astale et al. BMC Ophthalmol. .

Abstract

Background: Trachomatous scarring (TS) results from repeated infection with the bacterium Chlamydia trachomatis. Pronounced scarring is an underlying cause of trachomatous trichiasis (TT) that can lead to blindness. Since the condition is irreversible, TS in adults has been considered a marker of past exposure to trachoma infection. The aim of this report was to estimate the population-based prevalence of TS within Amhara, Ethiopia, a region with a historically high burden of trachoma.

Methods: District-level multi-stage cluster surveys were conducted in all districts between 2010 and 2015 to monitor the impact of approximately 5 years of trachoma interventions. Approximately 40 households were sampled per cluster and all participants ages ≥ 1 year were graded for the 5 World Health Organization simplified signs. Before each survey round, trachoma graders participated in a 7-day training and reliability exam that included cases of TS. TS prevalence estimates were weighted to account for sampling design and adjusted for age and sex using post-stratification weighting.

Results: Across the 152 districts in Amhara, 208,510 individuals ages 1 year and older were examined for the signs of trachoma. Region-wide, the prevalence of TS was 8.2 %, (95 % Confidence Interval [CI]: 7.7-8.6 %), and the prevalence among individuals ages 15 years and older (n = 110,137) was 12.6 % (95 % CI: 12.0-13.3 %). District-level TS prevalence among individuals ages 15 years and older ranged from 0.9 to 36.9 % and was moderately correlated with district prevalence of TT (r = 0.31; P < 0.001). The prevalence of TS increased with age, reaching 22.4 % among those ages 56 to 60 years and 24.2 % among those ages 61 to 65 years. Among children ages 1 to 15 years TS prevalence was 2.2 % (95 % CI: 1.8-2.8 %), increased with age (P < 0.001), and 5 % of individuals with TS also had trachomatous inflammation-intense (TI).

Conclusions: These results suggest that Amhara has had a long history of trachoma exposure and that a large population remains at risk for developing TT. It is promising, however, that children, many born after interventions began, have low levels of TS compared to other known trachoma-hyperendemic areas.

Keywords: Chlamydia trachomatis; Ethiopia; Survey; Trachoma; Trachomatous scarring.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
District-level TS prevalence among individuals ages 15 years and older, Amhara, Ethiopia, 2010 to 2015
Fig. 2
Fig. 2
District-level TS prevalence among individuals ages 15 years and older, Amhara, Ethiopia, 2010 to 2015
Fig. 3
Fig. 3
Scatterplot of district-level TS and TT prevalence, Amhara, Ethiopia, 2010 to 2015. N=152 districts, r=0.31
Fig. 4
Fig. 4
Prevalence of TS by sex and age group, Amhara, Ethiopia, 2010 to 2015
Fig. 5
Fig. 5
Prevalence of TS by sex and ages 1 to 15 years, Amhara, Ethiopia, 2010 to 2015
Fig. 6
Fig. 6
Active trachoma with TS prevalence in ages 1 to 15, Amhara, Ethiopia, 2010 to 2015
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