Exploring relationships of fecal exposure pathways & (a)symptomatic enteric infections in Vellore

American Society of Tropical Medicine and Hygiene 2019

November 20-24, 2019

Yuke Wang, Sydney Hubbard, Gagandeep Kang, Suraja Raj, Habib Yakubu, Arun Karthikeyan, Senthil Kumar, Venkata R. Mohan, Christine Moe

Emory University, Atlanta, GA, United States, Christian Medical College of Vellore, India, Vellore, India

Rapid urbanization has led to a sanitation crisis in many low- and middle income countries (LMIC). In March 2014, SaniPath in collaboration with the Christian Medical College (CMC) of Vellore, India conducted an exposure assessment in Old Town, a dense, urban unplanned settlement in Vellore. A total of 191 samples were collected from open drains, drinking water, public latrines, soil, raw produce, bathing water, child handrinse, and toy feeding spoon rinse and analyzed for E. coli. From March 2010 - February 2012, the MAL-ED study, a multi-site project examining enteric and growth outcomes enrolled a birth cohort of 190 children in Old Town. Multiple stool samples were collected from each child over two years of follow up and tested for bacterial and viral pathogens. Symptomatic illness was recorded. Each child in the MAL-ED study was linked with the closest environmental samples from the SaniPath study. Spatial variables, like the distance to the closest open defecation site, were generated. Generalized linear models were used with the bacterial infection rate, viral infection rate, and symptomatic illness rate as outcomes and environmental fecal contamination from different pathways and spatial variables as covariates. E. coli concentration from the closest public latrine and the distance to the closest open defecation site were significant predictors of bacterial infection rate in children. The sum of the open drain lengths within a 100-meter radius of the child, as well as the sum of street lengths within a 100-meter radius of the child, were significant predictors of viral infections in children. The E. coli concentration of the closest piped water was the only significant predictor of symptomatic illness in children. These results highlight the need for safe excreta management in dense, urban settings to prevent bacterial infections, while contaminated drinking water seems to be a major driver of symptomatic illness in this population. Human congestion, as proxied by summative surrounding street lengths and open drains, is a key risk factor for viral infection.

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Comparison of SaniPath Exposure Assessments in Low-Income Urban Areas in Eight Countries

UNC Water and Health Conference

Presenter: Wolfgang Mairinger

The SaniPath exposure assessment tool compares risks of exposure to fecal contamination in urban environments across multiple exposure pathways. The tool has been deployed in 39 neighborhoods in 8 cities: Accra, Ghana, Vellore, India; Maputo, Mozambique; Siem Reap, Cambodia; Dhaka, Bangladesh; Atlanta, United States; Lusaka, Zambia; and Kampala, Uganda. Ten exposure pathways were investigated (open drains, ocean water, surface water, floodwater, public latrines, soil, bathing water, raw produce, drinking water, and street food) through behavior surveys and environmental sample analyses. Exposure was expressed as monthly dose (average amount of fecal contamination ingested as measured by E. coli colony-forming units [CFU]) and the percent of population exposed to fecal contamination for each pathway. Magnitude of fecal contamination, frequency of exposure behavior, and estimated fecal exposures were compared across pathways, neighborhoods and cities. The most common dominant exposure pathways for adults were raw produce, open drains, and street food and for children were open drains, produce, and floodwater. For produce, the dose was usually very high (>106 CFU/month), and a large percent of the population was exposed (>80%). For street food, average E. coli concentration ranged from 101.3 CFU/serving in one neighborhood in Lusaka, Zambia to 105.5 CFU/serving in one neighborhood in Dhaka, Bangladesh. Exposure to open drains resulted in high doses (>104 CFU/month), but the population exposed varied (5%-92%) even within the same city. Exposure to fecal contamination via floodwater, usually affected a high percent of population (>80%) but had variable doses (102.5- 1010 CFU/month). Both dose and percent of population exposed varied for public latrines and municipal piped water. This information can help city governments choose effective interventions to reduce the risk of exposure to fecal contamination. Widespread risks from contaminated produce and street food within and across cities underscore the link between excreta management and food safety and need for global action.

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2019 Ghana National Sanitation Stakeholders Forum

Benedict Tuffuor, Ato Kwamena Senayah, and Joshua Tetteh-Nortey, partners at TREND Ghana and Kumasi Metropolitan Assembly, presented at the Ghana National Sanitation Stakeholders Forum on July 17th, 2019. Benedict presented on the establishment of TREND as a SaniPath Training Hub and the recent work they have conducted alongside metropolitan assemblies. Ato and Joshua provided a presentation on the use of data in sanitation intervention planning and decision making. Data from the 2018 SaniPath Exposure Assessment in Kumasi, Ghana were used to call attention to potential areas for intervention to improve public health by reducing exposure to fecal contamination. These presentations highlighted the capacity building activities of TREND pertaining to behavioral, environmental, and laboratory work involved in conducting exposure assessment data collection and the potential impact of results provided by this type of work. TREND is continuing in their role as a SaniPath Training Hub by disseminating results and sharing the experience of partner organizations to create demand within other municipal assemblies.

Access Training Hub Presentation Here Access Data in Decision Making Presentation Here