Elucidating fecal contamination exposure in low-income countries, the contribution from child feces disposal practices and soil ingestion, and links to child health

Sanitation;Hygiene;Fecal contamination;Enteric pathogen;Child feces;Stunting;Undernutrition;Soil ingestion;Geophagy

Bauza, Valerie

关键词: Sanitation;    Hygiene;    Fecal contamination;    Enteric pathogen;    Child feces;    Stunting;    Undernutrition;    Soil ingestion;    Geophagy;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99463/BAUZA-DISSERTATION-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Enteric pathogens transmitted via fecal-oral pathways cause enteric infections that have substantial health and human capital consequences, making it critical to reduce child exposure to fecal contamination. Current water, sanitation, and hygiene programs in low-income countries often focus on improving water delivery and toilet/latrine infrastructure to reduce pathogen exposure, but child exposure to fecal contamination can remain common after these types of improvements. The overarching goal of this research was to investigate fecal contamination and enteric pathogen transmission in low-income countries, with a focus on young children’s feces as a source of contamination, soil ingestion as an exposure point, and their effects on child health.First, the occurrence, magnitude, and distribution of fecal contamination and enteric pathogens were assessed along multiple transmission pathways for children in a densely-populated urban slum neighborhood of Nairobi, Kenya. There was a high frequency of pathogen detection at several exposure points (including stored drinking water, hands, tables, plates, floors, soil, standing water, open drainage ditches, and streams) despite all households having access to a toilet or latrine. The results also provided evidence that children were exposed to enteric pathogens from several exposure points simultaneously, that there were interactions between different transmission pathways, and that soil could be an important exposure point because of its high levels of enteric pathogens.Next, the role of poor child feces management practices for young children (who are not old enough to use a toilet facility themselves) was evaluated in the context of domestic fecal contamination and child health. A method to track fecal contamination from the feces of young children separately from older children/adults was developed, validated, and then used to analyze environmental samples collected from multiple exposure points inside and outside households. Young children’s feces dominated the human fecal contamination found in the majority of samples taken from the indoor environment (caregiver and child hands, tables, plates), older child/adult feces dominated the human fecal contamination found in the majority of samples taken from standing water and streams in the outdoor environment, and each source dominated the human fecal contamination found in an equal number of samples taken from open drainage ditches. These results provided evidence that young children’s feces substantially contribute to household fecal contamination. Next, nationally representative data from 34 low- and middle-income countries was used to evaluate associations between child feces disposal practices and child health. Disposal of child feces into an improved toilet was found to be strongly associated with improvements in child growth, suggesting that better child feces disposal practices could achieve greater child health benefits than only improving toilet access.Finally, this research investigated soil ingestion as a potential exposure pathway for fecal contamination. There were strong associations between soil ingestion and child diarrhea in an urban slum setting in Kenya and a rural setting in northern Ghana, despite high levels of finished floor in households in both settings. There was also a high prevalence of soil ingestion among children in both settings, indicating this is likely a common exposure pathway for children in low-income countries. Taken together, this work identified high levels of enteric pathogen contamination at numerous indoor and outdoor exposure points in an urban slum environment, performed detailed investigations of poor management of young children’s feces as a contamination source and soil ingestion as an exposure point, and linked both of these practices to negative health consequences in children.