TEF I: Is More Frequent Mass Treatment Necessary for Elimination of Infectious Trachoma?

Abstract

Purpose: : Trachoma accounts for an estimated 15% of visual loss worldwide. Mass antibiotic treatment for ocular chlamydial infection is a key element in the World Health Organization’s trachoma control program. However, re–infection is common and it is unclear what frequency of treatment is necessary to eliminate trachoma in hyper–endemic areas. We compare the prevalence of chlamydial infection in Ethiopian communities treated both annually and biannually with azithromycin. (Please note that these villages are different than those discussed in "TEF II", also a poster submitted by Proctor Foundation).

Methods: : Sixteen villages were randomized to annual or biannual mass azithromycin administrations. A total of 4,276 pre–school children were monitored for ocular chlamydial infection using Amplicor PCR at 2, 6, 12, 18, and 24 months after treatment. Analyses were performed at the village level.

Results: : For each visit, we monitored an average of 442 pre–school age children in the annually treated villages and 395 children in the biannually treated villages. In the annually treated villages, the prevalence of infection in pre–school children was reduced from a mean of 42.6% (range 14.7–56.4%) to 6.8% at 24 months (range 0.0–22%). In the biannually treated villages, pre–schhool infection was reduced from 31.6% pre–treatment (range 6.1–48.6%) to 0.9% at 24 months (range 0.0–5.0%). At 24 months, no infection could be identified in 6 of 8 biannually treated and 1 of 8 annually treated villages (P=0.03, controlling for baseline prevalence).

Conclusions: : Both annual and bi–annual community–wide antibiotic treatments are effective in reducing infections of ocular chlamydia to low levels among pre–school age children. However, treating biannually appears more likely to lead to elimination in areas of hyper–endemic trachoma.

Keywords: trachoma • antibiotics/antifungals/antiparasitics