Risk of Exposure to Fecal Contamination for Adults and Children in Neighborhoods Across Dhaka, Bangladesh Using the SaniPath Exposure Assessment Tool

S Raj, J Green, Y Wang, N Amin, M Rahman, I Hassan, Z Hassan, G Joseph, CL Moe

UNC Water and Health Conference (October 2018)

At the 2018 UNC Water and Health Conference in Chapel Hill, North Carolina, Suraja Raj presented on a SaniPath Exposure Assessment conducted in 10 neighborhoods (6 low-income 2 mixed-income and 2 high-income) throughout Dhaka between April-June 2017. 1000 environmental samples were collected from shared latrines, public play areas, produce in markets, street food, open drains, flood waters, surface waters, bathing water, municipal water, and non-municipal water. Samples were analyzed using IDEXX-Colilert-24® Quanti-Tray/2000 for most probable number (MPN) of E. coli. Behavior surveys were conducted with households, school children, and community groups to understand interaction with the environment. Using Bayesian methods, these data were used to estimate the percentage of the population exposed and mean dose of fecal exposure (E. coli) for each environmental pathway in each neighborhood. For adults, consumption of raw produce was the dominant exposure pathway (i.e. contributes most to total exposure) in 6 of 10 neighborhoods. 78-99% of adults were exposed to fecal contamination through ingestion of raw produce and the mean dose ranged from 104.8 – 107.5 MPN of E. coli ingested/month. The most common dominant among children (8/10 neighborhoods) was accidental ingestion of drain water from contact with open drains (up to 94% exposed; mean dose of 107.8 MPN of E. coli ingested/month). Ingestion of fecal contamination via produce and street food was a high risk throughout Dhaka while exposure to fecal contamination via municipal drinking water was a greater risk for those living in the south of the city. These results can guide city-wide WASH programming to prioritize interventions and increase the potential for public health impact.

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