1. The distribution of the prevalence of ocular chlamydial infection in communities where trachoma is disappearing.
- Author
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Lietman TM, Gebre T, Abdou A, Alemayehu W, Emerson P, Blumberg S, Keenan JD, and Porco TC
- Subjects
- Anti-Bacterial Agents therapeutic use, Azithromycin therapeutic use, Child, Child, Preschool, Cross-Sectional Studies, Ethiopia epidemiology, Female, Humans, Infant, Infant, Newborn, Longitudinal Studies, Male, Models, Theoretical, Prevalence, Chlamydia Infections epidemiology, Eye Infections, Bacterial epidemiology, Trachoma drug therapy, Trachoma epidemiology
- Abstract
Mathematical models predict that the prevalence of infection in different communities where an infectious disease is disappearing should approach a geometric distribution. Trachoma programs offer an opportunity to test this hypothesis, as the World Health Organization (WHO) has targeted trachoma to be eliminated as a public health concern by the year 2020. We assess the distribution of the community prevalence of childhood ocular chlamydia infection from periodic, cross-sectional surveys in two areas of Ethiopia. These surveys were taken in a controlled setting, where infection was documented to be disappearing over time. For both sets of surveys, the geometric distribution had the most parsimonious fit of the distributions tested, and goodness-of-fit testing was consistent with the prevalence of each community being drawn from a geometric distribution. When infection is disappearing, the single sufficient parameter describing a geometric distribution captures much of the distributional information found from examining every community. The relatively heavy tail of the geometric suggests that the presence of an occasional high-prevalence community is to be expected, and does not necessarily reflect a transmission hot spot or program failure. A single cross-sectional survey can reveal which direction a program is heading. A geometric distribution of the prevalence of infection across communities may be an encouraging sign, consistent with a disease on its way to eradication., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2015
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