Abstract
Purpose :
A cohort of children in formerly trachoma hyperendemic communities in Tanzania were followed over time, as they progressed into young adulthood, to determine longitudinal changes in clinical trachoma and infection rates, as well as scarring rates. The goal of this study was to evaluate changes in trachoma over time in children and to determine the effect of repeat mass drug administration (MDA) efforts on scarring rates in differing age groups.
Methods :
A prospective population-based longitudinal study was conducted in Kongwa, Tanzania. Cross sectional surveys for trachoma and ocular C. trachomatis infection were carried out in children aged 0-5 years at baseline and at 6, 12, 18, 60, 96, 102, and 108 months since baseline. Clinical grading of follicular trachoma (TF), inflammatory trachoma (TI), and scarring trachoma (TS) were done based on photographs, using the WHO simplified grading scheme. MDA with azithromycin was offered at baseline, 18, 60, and 96 months post baseline. Using prevalence data, the predicted rate of scarring in children was calculated.
Results :
At baseline, active clinical trachoma was 79% in children 5 and under. After successive rounds of mass treatment, clinical trachoma and infection declined to 23%, never reaching pre-treatment levels. From the 60 month to the 108 month surveys, scarring rates decreased markedly in the youngest age groups, but within ages 16-20 years little change was seen. The rate of scarring in 11-15 year olds, predicted to be at 35% at the 108 month survey from a previous model, was actually 20%.
Conclusions :
Clinical trachoma and infection appear to be gradually and persistently declining with the advent of repeat MDA in this formerly trachoma hyperendemic community. Predicted prevalences in scarring among 11-15 year olds appears not to have occurred. This suggests that changes that have happened to reduce scarring occurred in their first 1-15 years, co-incident with implementation of MDA as part of SAFE in this community.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.