Eliminating Infectious Trachoma With Antibiotics: Report From the TEF II Study in Ethiopia

Abstract

Purpose: : Trachoma is the leading cause of infectious blindness. The WHO recommends mass azithromycin distribution to control the ocular chlamydia and thus trachoma. Mathematical models have predicted that biannual treatments might be sufficient to eventually eliminate infection even in hyper–endemic regions. Here we test the hypothesis by monitoring infection in the communities in Ethiopia that are severaly affected with as high as 100% clinicial activity.

Methods: : 16 villages were randomly chosen from the hyper–endemic area in Gurage zone, Ethiopia, that is different from the region for TEF I study. All members of these villages were offered antibiotic treatments every 6 months. All pre–school children 1–5 years were monitored biannually before each treatment for 24 months. Conjunctival swabs taken from children were tested for chlamydial DNA with the Amplicor PCR test.

Results: : On average, 823 children aged from 1 to 5 years old were monitored for each visit. The average clinical activity in the study region was as high as 93.3% (95% CI 87.8%–96.5%) at baseline. Prevalence of chlamydial infection ranged from 26.3% to 85.7% at baseline. The average prevalence of infection fell from 65.9% (95% CI 57.1%–73.7%) at baseline to 2.0% (95% CI 1.1%–3.7%) at 24 months. Local elimination among 1–5 year old children was observed as early as 2 months after the initial mass azithromycin distribution and at 24 months, 4 out of 16 villages were free of infection in pre–school children.

Conclusions: : Even in the most severely affected villages, biannual community–wide antibiotic distribution can reduce ocular infection significantly. Therefore, elimination may be possible. However, it should be noted that infection returned to children in some villages where infection had not been identified at the previous visits. It might be due to re–infection of children from untreated adults or re–introduction from neighboring villages.

Keywords: trachoma • clinical (human) or epidemiologic studies: prevalence/incidence • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials