Complete elimination of trachoma in Ethiopia: Is it possible?

Trachoma is the leading cause of infectious blindness in the world. WHO has set a goal of reducing the trachoma disease burden to a level where it is no longer a public health concern by the year 2020. Over 20 million doses of oral azithromycin have already been distributed to treat the ocular strains of Chlamydia trachomatis that cause trachoma. Although the prevalence of infection has been dramatically reduced in treated areas, experts are still debating the long term rationale for the distributions. Others expect that measures such as hygiene and latrine construction will control infection after antibiotics are discontinued.

Elimination of ocular chlamydial infection from even the most severely affected community is theoretically possible, as long as distributions are repeated frequently enough and with high enough coverage. Here we demonstrate that six biannual distributions completely eliminated ocular chlamydial infection from two hyper-endemic communities in Southern Ethiopia. The villages in this cross-sectional survey were previously enrolled and monitored as part of a larger, group-randomized clinical trial (1). As they had the highest baseline prevalence of trachoma, they would presumably be the most difficult from which to completely eliminate infection. Before treatment, clinical activity by WHO criteria was 78% and 83% in the two villages. Average coverage across the six treatments was 90% and 94% of the entire population, respectively. In a survey of all age groups at 42 months after baseline, no evidence of ocular chlamydia was found in adults or children in either community.