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Jacob Tanner Cox, Harran Mkocha, Beatriz Munoz, Sheila West; Prevalence of trachomatous scarring in children in a formerly endemic district of Tanzania. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4793.
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The association between repeated ocular infections with Chlamydia trachomatis in childhood and scarring of the tarsal conjunctiva in adulthood is well established. Scarring in children has been observed in endemic areas. There are scant data on the prevalence of scarring in children in formerly endemic areas where interventions have reduced trachoma to lower levels. This cross-sectional study of 38 villages in the Kongwa District, Tanzania, investigates the prevalence of trachomatous scarring (TS) in children ages 1-9 years.
A random sample of 50 children ages 1-9 years were selected from each of the region’s 38 villages in which we had preexisting data dating back 18 months prior to the current survey. Each participant received an ocular examination and ocular test for active infection with C. trachomatous. Digital photographs (990; Nikon, Tokyo, Japan) of the upper right tarsal conjunctiva were taken to assess for TS. Photographs were reviewed by study members at Johns Hopkins Hospital at 5x magnification and level of scarring was graded according to a validated, four-step severity scale as developed by Wolle et al. Images were assessed by two graders. Any discordance in grading was openly adjudicated. Extended Mantel-Haenszel analysis for trend was used to assess for differences in scarring by age category. Village level differences were assessed via the Student’s t-test.
1,517 (79.9%) of children selected participated in this study. The prevalence of follicular trachoma was 3.6%, and of infection was 0.9%. The prevalence of scarring was 1.65%; this consisted of 1.05% grade 1 scarring, 0.40% grade 2 scarring, and 0.20% grade 3 scarring. Scarring prevalence increased with age (age 1-4.9 yr: 1.2%, age 6-8.9: 1.9%, age 9-10: 2.0%); this was not statistically significant (p-value 0.25). Of the 38 villages, 22 had no children with scarring. Of the 16 villages with one or more children who had scarring, no single village had a total of more than two children with scarring. 18 months prior to survey, the prevalence of active trachoma in the 16 villages with scarring in children was a mean of 8%, versus a mean of 5% in the 22 villages with no scarring (p-value 0.10).
In this formerly endemic district, scarring in children is rare. Prevalence increases modestly with age. There was no evidence of clustering of scarring by village.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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