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

Abstract

BackgroundTrachoma 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 findingsA 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 Conclusions/significanceIn 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.