Sanitation and water supply coverage thresholds associated with active trachoma: Modeling cross-sectional data from 13 countries

• Type of Material: Article
• Authors: Joshua Garn, Emory University; Sohie Boisson, World Health Organization; Rebecca Willis, Task Force for Global Health; Ana Bakhtiari, Task Force for Global Health; Tawfik al-Khatib, Sana'a University; Khaled Amer, Ministry of Health, Cairo; Wilfrid Batcho, Ministère de la Santé, Cotonou; Paul Courtright, University of Cape Town; Michael Dejene, Michael Dejene Public Health Consultancy Services; Andre Goepogui, Ministère de la Santé; Khumbo Kalua, Blantyre Institute for Community Ophthalmology, College of Medicine; Biruck Kebede, Disease Prevention and Control Directorate, Federal Ministry of Health, Addis Ababa; Colin K. Macleod, Sightsavers; Kouakou Llunga Marie Madeleine, Programme National de la Santé Oculaire et de la Lutte contre l'Onchocercose, Abidjan; Mariamo Saide Abdala Mbofana, Programa Nacional de Oftalmologia, Maputo; Caleb Mpyet, University of Cape Town; Jean Ndjemba, Direction de Lutte contre la Maladie, Kinshasa, Ministere de la Santé Publique, Republique Democratique du Congo; Nicholas Olobio, Department of Public Health, Federal Ministry of Health, Abuja, Nigeria; Alexandre L. Pavluck, International Trachoma Initiative, The Task Force for Global Health, Decatur; Oliver Sokana, Eye Department, Ministry of Health and Medical Services, Honiara, Solomon Islands; Khamphoua Southisombath, National Ophthalmology Center, Ministry of Health, Vientiane, Lao People’s Democratic Republic; Fasihah Taleo, World Health Organization; Anthony W. Solomon, London School of Hygiene & Tropical Medicine; Matthew Freeman, Emory University
• Language: English
• Date: 2018-01-01
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2018 Garn et al.
• License: Creative Commons Attribution 3.0 IGO License
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pntd.0006110
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 12
• Issue: 1
• Start Page: e0006110
• End Page: e0006110
• Grant/Funding Information: AWS was a Wellcome Trust Intermediate Clinical Fellow (098521) at the London School of Hygiene & Tropical Medicine, and is now a staff member of WHO.; The Global Trachoma Mapping Project (GTMP) was principally funded by a grant from the United Kingdom’s Department for International Development (ARIES: 203145) to Sightsavers, which led a consortium of non-governmental organizations and academic institutions to support health ministries to complete baseline trachoma mapping worldwide.; MCF has received funding as a consultant for WHO as part of separate assessments of sanitation on health; A committee established in March 2012 to examine issues surrounding completion of global trachoma mapping was initially funded by a grant from Pfizer to the International Trachoma Initiative.; SB and AWS are employees of WHO, and JVG received funding from WHO to do this project.; JVG was supported by the World Health Organization (WHO) with funding from the United Kingdom’s Department for International Development.; The GTMP was also funded by the United States Agency for International Development (USAID), through the ENVISION project implemented by RTI International under cooperative agreement number AID-OAA-A-11-00048, and the END in Asia project implemented by FHI360 under cooperative agreement number OAA-A-10-00051.
• Keywords: PROGRAM; REGION; ETHIOPIA; HERD PROTECTION; CLUSTER-RANDOMIZED TRIAL; Infectious Diseases; Parasitology; STATE; Science & Technology; MAPPING PROJECT; PREVALENCE SURVEYS; LATRINE PROMOTION; Life Sciences & Biomedicine; Tropical Medicine; RISK-FACTORS
• Research Categories: Biology, Parasitology; Health Sciences, Medicine and Surgery; Engineering, Biomedical

Abstract

Facial cleanliness and sanitation are postulated to reduce trachoma transmission, but there are no previous data on community-level herd protection thresholds. We characterize associations between active trachoma, access to improved sanitation facilities, and access to improved water sources for the purpose of face washing, with the aim of estimating community-level or herd protection thresholds. Methods and findings: We used cluster-sampled Global Trachoma Mapping Project data on 884,850 children aged 1–9 years from 354,990 households in 13 countries. We employed multivariable mixed-effects modified Poisson regression models to assess the relationships between water and sanitation coverage and trachomatous inflammation—follicular (TF). We observed lower TF prevalence among those with household-level access to improved sanitation (prevalence ratio, PR = 0.87; 95%CI: 0.83–0.91), and household-level access to an improved washing water source in the residence/yard (PR = 0.81; 95%CI: 0.75–0.88). Controlling for household-level water and latrine access, we found evidence of community-level protection against TF for children living in communities with high sanitation coverage (PR 80–90% = 0.87; 95%CI: 0.73–1.02; PR 90–100% = 0.76; 95%CI: 0.67–0.85). Community sanitation coverage levels greater than 80% were associated with herd protection against TF (PR = 0.77; 95%CI: 0.62–0.97)—that is, lower TF in individuals whose households lacked individual sanitation but who lived in communities with high sanitation coverage. For community-level water coverage, there was no apparent threshold, although we observed lower TF among several of the higher deciles of community-level water coverage. Conclusions: Our study provides insights into the community water and sanitation coverage levels that might be required to best control trachoma. Our results suggest access to adequate water and sanitation can be important components in working towards the 2020 target of eliminating trachoma as a public health problem.