Transmission of fecal contamination to stored drinking water in unplanned settlements in Lusaka

Drinking water stored at home is often prone to fecal contamination in unplanned settlements. The present study investigated the transmission pathways of fecal contamination to stored tap water in peri-urban Lusaka, Zambia. Samples from stored tap water (n = 21), kitchenware (n = 50), floor surfaces (n = 80), and flies in living spaces (n = 304) were collected in October and November 2019 and tested for Escherichia coli. Path analysis showed two major transmission routes to stored tap water contamination: (1) from house-entrance floor to cups (path coefficient (β): 0.37) and then to stored tap water (β: 0.92), and (2) from flies at house entrance to flies inside kitchen (β: 0.78), then to cups (β: 0.57), and finally to stored tap water (β: 0.92). Cups were the key transmission medium, potentially contaminated from house entrances and by flies in the kitchen. The findings highlight the critical role of cup and floor cleaning and fly control in living spaces in protecting stored drinking water in poor water, sanitation, and hygiene environments.