Multipathway Quantitative Assessment of Exposure to Fecal Contamination for Young Children in Low-Income Urban Environments in Accra, Ghana: The SaniPath Analytical Approach

• Authors: Yuke Wang, Emory University; Christine L Moe, Emory University; Alex Null, Emory University; Suraja J. Raj, Emory University; Kelly Baker, Emory University; Katharine A. Robb, Emory University; Habib Yakubu, Emory University; Joseph A. Ampofo, Council for Scientific and Industrial Research; Nii Wellington, Training Research and Networking for Development; Matthew Freeman, Emory University; George Armah, University of Ghana; Heather E. Reese, Emory University; Dorothy Peprah, Emory University; Peter Teunis, Emory University
• Journal Title: American Journal of Tropical Medicine and Hygiene
• Volume: Volume 97, Number 4
• Publisher: American Society of Tropical Medicine and Hygiene | 2017-10-11, Pages 1009-1019
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.4269/ajtmh.16-0408
• Subjects: Health Sciences, Epidemiology; Health Sciences, Public Health; Health Sciences, Hygiene
• Keywords: Science & Technology; Life Sciences & Biomedicine; Public, Environmental & Occupational Health; Tropical Medicine; MICROBIAL RISK-ASSESSMENT; DOSE-RESPONSE; CHILDHOOD DIARRHEA; DRINKING-WATER; SANITATION; HYGIENE; INTERVENTIONS; NUTRITION; INFECTION; PATHOGENS

Abstract

Lack of adequate sanitation results in fecal contamination of the environment and poses a risk of disease transmission via multiple exposure pathways. To better understand how eight different sources contribute to overall exposure to fecal contamination, we quantified exposure through multiple pathways for children under 5 years old in four high-density, low-income, urban neighborhoods in Accra, Ghana. We collected more than 500 hours of structured observation of behaviors of 156 children, 800 household surveys, and 1,855 environmental samples. Data were analyzed using Bayesian models, estimating the environmental and behavioral factors associated with exposure to fecal contamination. These estimates were applied in exposure models simulating sequences of behaviors and transfers of fecal indicators. This approach allows us to identify the contribution of any sources of fecal contamination in the environment to child exposure and use dynamic fecal microbe transfer networks to track fecal indicators from the environment to oral ingestion. The contributions of different sources to exposure were categorized into four types (high/low by dose and frequency), as a basis for ranking pathways by the potential to reduce exposure. Although we observed variation in estimated exposure (108-1016 CFU/day for Escherichia coli ) between different age groups and neighborhoods, the greatest contribution was consistently from food (contributing > 99.9% to total exposure). Hands played a pivotal role in fecal microbe transfer, linking environmental sources to oral ingestion. The fecal microbe transfer network constructed here provides a systematic approach to study the complex interaction between contaminated environment and human behavior on exposure to fecal contamination.