Enteric pathogens from water, hands, surface, soil, drainage ditch, and stream exposure points in a low-income neighborhood of Nairobi, Kenya

Abstract

Child exposure to fecal-oral pathogens occurs through several transmission pathways. However, the relative importance of different exposure points for pathogen transmission both inside and outside households is not well understood. We conducted a cross-sectional study in the urban slum of Kibera in Nairobi, Kenya, collecting 237 environmental samples from 40 households from source water, stored drinking water, caregiver hands, child hands, household surfaces, soil, standing water, open drainage ditches, and streams. We quantified the fecal indicator Escherichia coli and the enteric pathogens of adenovirus, Campylobacter jejuni, Shigella spp./enteroinvasive E. coli (EIEC), and Vibrio cholerae. At least one enteric pathogens was detected in 13% of household stored water, 47% of hand, 46% of table surface, 26% of plate surface, 75% of floor surface, 96% of soil, 56% of standing water, 77% of drainage ditch, and 100% of stream samples despite all households having access to a toilet or latrine. Our results provide evidence that children may be exposed to enteric pathogens from several exposure points, that domestic hygiene practices related to water treatment and child handwashing were associated with reduced pathogen detection in this setting, but household table and floor cleaning practices were not, that ownership or presence of chickens in the compound was associated with increased detection of C. jejuni inside households and on soil, that there were interactions among different transmission pathways for enteric pathogens, and that there were differential correlations between E. coli and enteric pathogens for different pathogens and environmental sample types. Additionally, V. cholerae was detected at several exposure points during a cholera outbreak. Overall, these results suggest that interventions that can disrupt many transmission pathways may be needed to reduce enteric pathogen exposure in this urban slum setting.