Incidence and progression of trachomatous scarring in a cohort of children in a formerly hyper-endemic district of Tanzania.

Background Trachoma is the leading infectious cause of blindness. Repeated or persistent ocular infection with Chlamydia trachomatis in childhood leads to conjunctival scarring, usually in adulthood but often earlier in areas with greater disease burden. There are limited longitudinal data examining...

Full description

Bibliographic Details
Published in:PLOS Neglected Tropical Diseases
Main Authors: Michael Saheb Kashaf, Beatriz E Muñoz, Harran Mkocha, Meraf A Wolle, Fahd Naufal, Sheila K West
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2020
Subjects:
Online Access:https://doi.org/10.1371/journal.pntd.0008708
https://doaj.org/article/04efdd9653ff422990daf275b09492a7
Description
Summary:Background Trachoma is the leading infectious cause of blindness. Repeated or persistent ocular infection with Chlamydia trachomatis in childhood leads to conjunctival scarring, usually in adulthood but often earlier in areas with greater disease burden. There are limited longitudinal data examining change in scarring in children, especially where trachoma rates are low. Methodology/principal findings A cohort of children, ages 1-9 years, were randomly selected at baseline from 38 communities in Kongwa, Tanzania and followed for 2 years. Rates of trachomatous inflammation-follicular (TF) were <5% over the survey period. At baseline, 1,496 children were recruited and 1,266 (85%) were followed-up. Photographs were obtained at baseline and follow-up and graded for the presence and severity of scarring using a four-point scale ranging between S1-S4. In children without scarring at baseline, 1.6% (20/1,246) were found to have incident scarring, and incident scarring was more common among girls compared to boys. Among children with scarring at baseline, 21% (4/19) demonstrated progression. Conclusions/significance In this formerly hyper-endemic district, the incidence of new scarring in children ages 1-9 years is low, although 21% of those who had scarring at baseline progressed in severity over the 2-year follow-up period. These data provide support for the thesis that while incident scarring more closely reflects ongoing exposure, progression may involve factors independent of ongoing transmission of trachoma.