Characterization and measurement of child exposure to zoonotic enteric pathogens in Esmeraldas Province, Ecuador Restricted; Files Only
Ballard, April (Spring 2023)
Published
Abstract
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 focus on exposure to human feces, overlooking transmission pathways related to animal feces. The goal of this dissertation is to better understand if, why, how, and to what extent children are exposed to zoonotic enteric pathogens through 3 research aims.
Aim 1 characterized exposure among children aged 6-18 months old in northwestern coastal Ecuador. We conducted qualitative interviews with caregivers in households that owned and did not animals. We found that animals and their feces were ubiquitous – regardless of animal ownership – due to animal husbandry and feces management practices at the household- and community-level.
Aim 2 examined what types of animal fecal exposures have been assessed in human studies by auditing existing measurement. Exposure measures from included studies were classified in two ways. First, using a novel conceptual model, we categorized measures into ‘Exposure Components’ that were identified a priori: animal, environmental, and human behavioral. Second, using the exposure science conceptual framework, we determined where measures fell along the source-to-outcome continuum. Results revealed that existing measurement approaches are diverse and distal from exposure.
Aim 3 developed and validated a novel measure of child exposure to zoonotic enteric pathogens, and assessed exposure among children aged 6 months to 5 years old in northwestern coastal Ecuador. Using findings from aims 1 and 2, we generated a survey that we administered to mothers. We conducted principal component analysis to determine the optimal number of components and items to create an index to quantify exposure. The final measure consisted of seven interpretable components and 34 items. We found that child exposure to zoonotic enteric pathogens was ubiquitous. Only two children had no exposure.
Findings from this dissertation fill evidence gaps that improve the conception and measurement of child exposure to zoonotic enteric pathogens, which can enable and expand researchers’ and practitioners’ ability to assess exposure and develop and evaluate interventions.
Table of Contents
Chapter 1. Introduction .............................................................................................................................. 1
1.1. Motivation .......................................................................................................................................... 1
1.2. Exposure to zoonotic enteric pathogens ............................................................................................. 2
1.3. Dissertation research .......................................................................................................................... 6
1.4. Dissertation aims ................................................................................................................................ 9
Research aim 1 ...................................................................................................................................... 9
Research aim 2 ...................................................................................................................................... 9
Research aim 3 ...................................................................................................................................... 9
1.5. Study setting ..................................................................................................................................... 10
1.6. Study design ..................................................................................................................................... 11
1.7. References ........................................................................................................................................ 13
Chapter 2. Research Aim 1: Child exposure to zoonotic enteric pathogens in northwestern coastal Ecuador: A qualitative study ....................................................................................................................... 19
2.1. Abstract ............................................................................................................................................ 19
2.2. Introduction ...................................................................................................................................... 20
2.3. Methods ............................................................................................................................................ 21
Study design and setting ..................................................................................................................... 21
Sample and participant selection ......................................................................................................... 22
Data collection .................................................................................................................................... 24
Data analysis ....................................................................................................................................... 26
Ethics .................................................................................................................................................. 27
2.4. Results .............................................................................................................................................. 27
Inside the household ........................................................................................................................... 27
Outside the household ......................................................................................................................... 33
Other non-household locations ........................................................................................................... 38
2.5. Discussion ........................................................................................................................................ 40
Strengths and Limitations ................................................................................................................... 43
Conclusions ......................................................................................................................................... 43
2.6. References ........................................................................................................................................ 45
Chapter 3. Research Aim 2: Measurement in the study of human exposure to animal feces: A systematic review and audit .......................................................................................................................................... 50
3.1. Abstract ............................................................................................................................................ 50
3.2. Introduction ...................................................................................................................................... 51
3.3. Methods ............................................................................................................................................ 54
Search strategy .................................................................................................................................... 54
Study eligibility ................................................................................................................................... 55
Data extraction and synthesis .............................................................................................................. 57
Quality appraisal ................................................................................................................................. 58
Data synthesis ..................................................................................................................................... 59
3.4. Results .............................................................................................................................................. 60
Theoretical and operational definitions of exposure ........................................................................... 61
Exposure measurement ....................................................................................................................... 63
Exposure Components ........................................................................................................................ 65
Exposure science conceptual framework ............................................................................................ 71
Properties of tools ............................................................................................................................... 71
3.5. Discussion ........................................................................................................................................ 72
Strengths and Limitations ................................................................................................................... 77
Conclusion .......................................................................................................................................... 78
3.6. References ........................................................................................................................................ 79
Chapter 4. Research Aim 3: The development and validation of a survey to measure fecal-oral child exposure to zoonotic enteropathogens: The FECEZ Enteropathogens index ............................................. 87
4.1. Abstract ............................................................................................................................................ 87
4.2. Introduction ...................................................................................................................................... 88
4.3. Methods ............................................................................................................................................ 89
Defining and conceptualizing child exposure to zoonotic enteric pathogens ..................................... 89
Setting ................................................................................................................................................. 90
Overview of research design ............................................................................................................... 91
Phase 1: Item Development ................................................................................................................ 92
Phase 2: Index Development .............................................................................................................. 94
Phase 3: Index Evaluation ................................................................................................................... 97
Ethics .................................................................................................................................................. 98
4.4. Results .............................................................................................................................................. 99
Participant Demographics ................................................................................................................... 99
Index Evaluation ................................................................................................................................... 103
4.5. Discussion ...................................................................................................................................... 106
Strengths and Limitations ................................................................................................................. 109
Conclusion ........................................................................................................................................ 110
4.6. References ...................................................................................................................................... 111
Chapter 5. Summary, implications and future directions ................................................................... 115
5.1. Summary of findings ...................................................................................................................... 115
5.2. Limitations ..................................................................................................................................... 117
5.3. Implications .................................................................................................................................... 118
5.4. Future directions ............................................................................................................................ 123
5.5. References ...................................................................................................................................... 126
Chapter 6. Appendix ............................................................................................................................... 130
6.1. Research aim 2 Supporting information ........................................................................................ 130
6.2. Research aim 3 Supporting information ........................................................................................ 169
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File download under embargo until 22 May 2025 | 2023-04-07 11:46:37 -0400 | File download under embargo until 22 May 2025 |
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