Measurement in the study of human exposure to animal feces: A systematic review and audit

Multilevel factors drive child exposure to enteric pathogens in animal feces: A qualitative study in northwestern coastal Ecuador

Exposure to animal feces and associated enteric pathogens poses significant risks to child health. However, public health strategies to mitigate enteric infections among children largely aim to reduce exposure to human feces, overlooking transmission pathways related to animal feces. In this study we examine if and how children are exposed to enteric pathogens in animal feces in northwestern coastal Ecuador. We conducted qualitative interviews with mothers of children aged 10-18 months that owned (n = 32) and did not own (n = 26) animals in urban and rural communities. Using thematic analysis, we identified community, household, and child behavioral factors that influence exposure. We also compared child exposure by household animal ownership. Our findings revealed myriad opportunities for young children to be exposed to enteric pathogens in many locations and from multiple animal sources, regardless of household animal ownership. Animal feces management practices (AFM) used by mothers, such as rinsing feces into ditches and throwing feces into surrounding areas, may increase environmental contamination outside their homes and in their communities. Unsafe AFM practices were similar to unsafe child feces management practices reported in other studies, including practices related to defecation location, feces removal and disposal, environmental contamination cleaning, and handwashing. Findings suggest that animal feces may contaminate the environment along similar pathways as human feces. Identification and incorporation of safe AFM practices, similar to those developed for child feces management, would 1) mitigate child exposure to enteric pathogens by reducing animal feces contamination in domestic and public spaces; and 2) enable an integrated approach to address enteric pathogen exposure pathways related to animal and child feces.

The development and validation of a survey to measure fecal-oral child exposure to zoonotic enteropathogens: The FECEZ Enteropathogens Index

Child exposure to animal feces and associated enteropathogens contribute to a significant burden of disease in low- and middle-income countries. However, there are no standardized, validated survey-based approaches to enable accurate assessment of child exposure to zoonotic enteropathogens. We developed and validated a survey-based measure of exposure, the fecal-oral child exposure to zoonotic enteropathogens Index (the FECEZ Enteropathogens Index). First, we identified critical attributes of child exposure through in-depth interviews (IDIs) in Ecuador among individuals who care for animals (n = 29) and mothers of children under two years old (n = 58), and through a systematic review of existing exposure measures. Second, based on these findings, we developed a 105-question survey and administered it to 297 mothers with children under age five. Third, we refined the survey, using principal component analysis to determine the optimal number of components. The final index consisted of 34 items across two sub-domains: the child Environment and child Behavior. Lastly, we compared index scores to two commonly used, unvalidated measures of child exposure-maternal reported household animal ownership and presence of animal feces. Using the FECEZ Enteropathogens Index revealed varying degrees of exposure in our study population, with only two children having no exposure. In contrast, if we had used animal ownership or the presence of animal feces as a measure of exposure, 44% and 33% of children would have been classified as having no exposure, respectively. These common binary exposure measures may be inadequate because they do not provide sufficient information to identify the relative risk of zoonotic pathogen exposure. The FECEZ Enteropathogens Index overcomes this limitation, advancing our ability to assess exposure by quantifying the multiple components of child exposure to zoonotic enteropathogens with higher resolution. Additional testing and evaluation of the index is needed to ensure its reliability, validity, and cross-cultural equivalence in other contexts.

Perspective: Connecting the dots between domestic livestock ownership and child linear growth in low- and middle-income countries

Child stunting due to linear growth faltering remains a pervasive issue in low- and middle-income countries. Two schools of thought have existed pertaining to the role of domestic livestock ownership (DLO) in child linear growth. On one hand, it is argued that DLO leads to greater income and financial security, resulting in better child-raising conditions, including greater animal-source food (ASF) consumption, having protective effects towards child stunting. On the other hand, researchers argue that DLO contributes to faecal contamination and transmission of zoonotic enteric infections from animals to children, thus having destructive effects on child growth. Reviews of this association have revealed ambiguous findings. In this perspective, we argue that measuring the association between exposures to domesticated animals and child stunting is difficult and the ambiguous associations revealed are a result of confounding and differences in the management of DLO. We also argue that the increasingly prominent area of research of environmental enteric dysfunction, a sub-clinical condition of the small intestine thought to be due to frequent faecal pathogen exposure and associated with stunting, will be a useful tool to measure the potential destructive effects of DLO on child growth. We present our argument and identify challenges and considerations and directions for future research.