Prevalence of Chlamydia trachomatis-Specific Antibodies before and after Mass Drug Administration for Trachoma in Community-Wide Surveys of Four Communities in Nepal.

Sarah E Gwyn,Lingwei Xiang,Diana L Martin,Deborah Dean,Manoj Gambhir,Ram Prasad Kandel

doi:10.4269/ajtmh.17-0102

Abstract

.The target end date for the global elimination of trachoma as a public health problem is 2020. As countries begin the process for submitting their dossier for the validation of elimination of trachoma as a public health problem, strategies for post-validation surveillance must be considered. Seroprevalence of antibodies against antigens from the causative bacteria Chlamydia trachomatis (Ct) in young children has been shown to reflect trachomatous inflammation–follicular (TF) rates in both endemic and previously endemic settings. However, none of these studies has directly compared age seroprevalence in the same communities before and after mass drug administration (MDA) for trachoma. Here we report a marked shift in age seroprevalence curves in four villages in Kapilvastu District, Nepal, before and after MDA. Clinical examinations were performed and blood was taken before (N = 659) and 5 years after (N = 646) MDA. Rates of TF decreased from 17.6% in ≤ 9-year-olds before MDA (N = 52) to 0% in ≤ 9-year-olds (N = 73) after MDA. Positive antibody responses to Ct in the entire population decreased from 82.1% pre-MDA to 35.8% post-MDA, whereas those among ≤ 9-year-olds decreased from 59.6% to 4.1%. These data show that the postintervention decrease in TF was reflected in a drop in anti-Ct antibody responses, suggesting that antibody responses could be useful indicators for post-validation surveillance.

Highlights

Trachoma is caused by repeated ocular infection with Chlamydia trachomatis (Ct) and is the leading infectious cause of blindness in the world today
Efforts by the World Health Organization (WHO) and other partners are underway to eliminate trachoma as a public health problem by 2020 through implementation of the SAFE strategy: surgery to correct trichiasis, mass drug administration (MDA) of antibiotics for all individuals living in endemic districts, facial cleanliness, and environmental improvement
The current WHO endpoint for MDA is a prevalence of trachomatous inflammation–follicular (TF) of < 5% in children aged 1–9 years district-wide

Summary

Introduction

Trachoma is caused by repeated ocular infection with Chlamydia trachomatis (Ct) and is the leading infectious cause of blindness in the world today. Efforts by the World Health Organization (WHO) and other partners are underway to eliminate trachoma as a public health problem by 2020 through implementation of the SAFE strategy: surgery to correct trichiasis (one or more eyelashes rubbing against the globe of the eye), mass drug administration (MDA) of antibiotics for all individuals living in endemic districts, facial cleanliness, and environmental improvement. As MDA programs strive to reduce infection prevalence, and efforts to eliminate trachoma are intensified, post-elimination surveillance will become an increasing programmatic priority and challenge. Funding for TF-based surveillance is unlikely to be a priority in postelimination settings, and in hypoendemic settings, follicular conjunctivitis may be caused by non-chlamydial bacteria and misdiagnosed as trachoma.[1] Clinical examinations can be difficult to standardize across trained staff,[2,3,4,5] and this difficulty will increase as the prevalence of TF decreases in

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