Taking care of the backside: Aspects of the sanitation chain beyond the household toilet and their associations with fecal contamination in the public and private domains and enteric infection risk in children Public

Berendes, David (2016)

Permanent URL: https://etd.library.emory.edu/concern/etds/8g84mm772?locale=fr
Published

Abstract

Enteric infections cause over 1.7 billion cases of diarrhea each year and other long-term morbidity, especially in children. Exposure to fecal contamination, and subsequent enteric infection risk, occurs in both public and private domains, especially in urban slums, where interactions between household-level sanitation, neighborhood-level fecal sludge management (FSM), and fecal contamination are poorly understood. This dissertation examined the interactions of household sanitation and FSM, and their spatial heterogeneity, in poor urban neighborhoods in Accra, Ghana and Vellore, India, and evaluated associations with fecal contamination in both domains and risk of enteric infection. Household surveys described household and neighborhood structural and behavioral risk factors, which were tested for local spatial clustering and overlaid on drainage maps. Fecal indicator bacteria and selected enteric pathogens were quantified in environmental samples inside and outside the household. Stool samples collected from children in both cross-sectional and longitudinal studies were tested for a panel of enteropathogens. Associations between microbiological outcomes and household or neighborhood risk factors were examined by generalized linear models. Cross-sectional study results in Accra indicated that sub-neighborhood clustering of household sanitation with good FSM was associated with lower levels of fecal indicator bacteria, but not human enteric viruses, in open drains. Cross-sectional study results from Vellore suggested that poor FSM was associated with higher prevalence of pediatric enteric infection and higher concentrations of norovirus in drains. Further, associations between household sanitation and within-household fecal contamination varied by neighborhood coverage level and household hygiene practices. The longitudinal assessment of enteric infection in 0-2 year olds suggested that aspects of neighborhood-level FSM and urban geography--clustering of flooding during a monsoon--affect enteric infection risk independent of exposure behaviors. Further, enteric viruses were major causes of diarrhea with atypical associations with "traditional" water, sanitation, and hygiene-associated risk factors, requiring new strategies for mitigation. Overall, this dissertation underscores the importance of the public domain and urban geography in fecal contamination exposures and enteric infection risk. The spatial heterogeneity and FSM associated with household sanitation have community-level exposure and health implications, which must be measured and accounted for in future infrastructural and behavioral interventions.

Table of Contents

Introduction 1

Enteric organisms and environmental transmission 1

Sanitation-related approaches to containing enteric organisms and fecal contamination 3

Figure I-1: The F-diagram 4

Spatial Analysis and WASH-associated Infections 6

Measurement of health outcomes 8

Measurement of exposure outcomes 9

Sanitation and Risk of Exposure to Fecal Contamination in the Urban Environment 14

Recent approaches to quantifying health risks from poor urban sanitation 19

Study cities 22

Rationale and Aims of the Dissertation 23

Urban Sanitation Coverage and Environmental Fecal Contamination: Links Between the Household and Public Environments 25

Abstract 26

Introduction 27

Methods 29

Study Site 29

Ethics 30

Environmental Sampling and Processing 30

Household Surveys 31

Public Toilet Surveys 32

Analyses 33

Results 35

Neighborhood demographics and coverage/clustering of household sanitation 35

Variation in environmental fecal contamination between urban neighborhoods and by season 36

Variation in environmental fecal contamination by animal ownership and population density 37

Variation in E. coli contamination in soil by neighborhood sanitation 37

Variation in E. coli contamination in drain water by neighborhood sanitation 38

Variation in enteric virus detection in drain water by neighborhood sanitation 39

Discussion 40

Tables and Figures 47

Table 1: Population density, animal ownership, and neighborhood sanitation, including spatial clustering 47

Table 2: E. coli concentrations and enteric virus detection in public domain samples, by neighborhood 48

Table 3: E. coli contamination in soil in the public domain by sanitation coverage cluster 49

Table 4: E. coli contamination in public drains by sanitation coverage cluster 50

Figure 1: Neighborhood sanitation coverage and sample sites, Shiabu, Accra, Ghana 51

Supporting Information (SI) 52

Table S1: E. coli contamination in soil and drains by season, population density, and local household animal ownership 54

Table S2: E. coli contamination in soil in the public domain by local sanitation coverage 54

Table S3: E. coli contamination in public drains by local sanitation coverage 55

Table S4: Adenovirus, NoV GI, and NoV GII contamination in public drains by local sanitation 56

Table S5: Adenovirus, NoV GI, and NoV GII contamination in public drains by sanitation coverage cluster 57

The Influence of Household- and Community-Level Sanitation and Fecal Sludge Management on Urban Fecal Contamination in Households and Drains and Enteric Infection in Children 59

Abstract 60

Introduction 61

Materials and Methods 63

Data source 63

Study site 64

Ethical approval 65

Environmental and stool sample collection, analysis, and processing 65

Survey data collection 69

Analyses 69

Results 71

Frequency and within-neighborhood spatial clustering of household sanitation 71

Microbiological concentrations in environmental samples and enteric pathogen detection in stool 72

Association between household- and cluster-level sanitation coverage, FSM practices, and within-household fecal contamination 74

Association between demographics, neighborhood, and household- and cluster-level sanitation variables and fecal contamination outside the household 75

Household- and cluster-level sanitation and enteric infection in children 76

Discussion 76

Tables and Figures 84

Table 1: Reported frequency and clustering of household sanitation and fecal sludge management (FSM) in Chinnallapuram and Old Town 84

Table 2: Variation in detection and concentrations of E. coli in environmental samples within households with neighborhood and hygiene status 85

Table 3: Variation in detection of enteric pathogens in stool with neighborhood and hygiene statusa 85

Table 4: Variation in GII norovirus detection and concentration in drain water 86

Table 5: Any enteric pathogen detection in child stoola by household- and cluster-level attributesb 87

Figure 1a: Sanitation coverage and clustering in Chinnallapuram. 88

Figure 1b: Sanitation coverage and clustering in Old Town 89

Supplemental Information 90

Table S1: Analysis of E. coli concentrations in child hand rinses by household- and cluster-level sanitation and FSMa 90

Table S2: Analysis of E. coli concentrations in household swabs by household- and cluster-level sanitation and FSMa 91

Table S3: Analysis of E. coli concentrations in sentinel object rinses by household- and cluster-level sanitation and FSMa 92

Risk Factors for Pediatric Enteric Infection in a Low-Income Urban Neighborhood: Examining the Contributions of the Household Environment, Neighborhood Geography, and Exposure Behaviors 93

Abstract 94

Author Summary 95

Introduction 96

Methods 99

Data sources 99

Study site 99

Ethical approval 100

Stool specimen collection and testing 100

Transect walks and household survey data collection: SaniPath Tool 101

Survey data collection: public toilet surveys 102

Analyses 102

Results 103

Household and neighborhood environments and exposure behaviors in the study neighborhood 103

Public toilet maintenance and conditions 105

Distribution of pathogenic organisms in children's stool 105

Pathogens associated with diarrheal stool 106

Spatial and temporal clustering of enteric infections 106

Effect of household and neighborhood environments on enteric infection risk, by pathogen type 107

Effect of exposure behaviors on enteric infection risk, by pathogen type 109

Multivariate modeling of enteric infection, by pathogen type 110

Discussion 111

Tables and Figures 119

Table 1: Reported household/neighborhood conditions and exposure behaviorsa 119

Table 2: Detection of pathogens in children's stool in SaniPath and all MAL-ED households from 2010-2014 120

Table 3: Bivariate relationships between household and neighborhood conditions and pathogen detection in stool collected from children in SaniPath households, 2010-2014a 121

Table 4: Bivariate relationships between spatial clustering of flooding in neighborhood, seasonality, and pathogen detection in stool collected from children in SaniPath households, 2010-2014a 122

Table 5: Bivariate relationships between household exposure behaviors and pathogen detection in stool collected from children in SaniPath households, 2010-2014a 123

Table 6: Multivariate fecal exposure models by pathogen group for children in SaniPath households, 2010-2014a 124

Figure 1: Reported drain and house flood clustering, Old Town 125

Figure 2: Space-time clustering of infections, Old Town, 2011 126

Figure 3: Space-time clustering of infections, Old Town, 2012 127

Conclusions 128

Strengths and Limitations 131

Future Directions 135

Policy and Involvement of Local Governments and Communities 136

Research and Evaluation 138

Contribution to the field 141

Appendix: Additional analyses and data 142

Aim 1 (Accra, Ghana) 142

Associations between drain size, construction, and detection of enteric viruses 142

Associations between sanitation variables and Ct values of enteric viruses in Accra, Ghana 145

Table A1.2: Adenovirus, NoV GI, and NoV GII Ct values for public drain water by local sanitation prevalence in Accra, Ghana 147

Table A1.3: Adenovirus, NoV GI, and NoV GII Ct values for public drain water by sanitation coverage cluster in Accra, Ghana 148

Aim 2 (Vellore, India) 149

Christian Medical College Hygiene Survey 149

Correlation between fecal contamination levels in different types of environmental samples 149

Table A2.1: Correlations between sample types within and outside the household 150

Further spatial analysis in Vellore, India 151

Final multivariate fecal contamination models 152

Fecal contamination associations with enteric infection 155

Table A2.3: Any enteric pathogen detection in child stool by E. coli concentrations in environmental samples 155

Aim 3 (Vellore, India) 156

Methods: Model for mixed-effects logistic regression (logistic regression with a random intercept) 156

Burden of enteric infection 156

Differences in burden of enteric infection by follow-up period 162

Incidence of enteric infection during the first two years of life 167

Tests of global autocorrelation, local autocorrelation, and spatial clustering for burden of enteric infection 173

Tests of global autocorrelation for residuals of final models in Aim 3 174

Spatial network-based clustering analysis of enteric infection 174

Tests of spatial, temporal, and space-time clustering of coinfections 183

Tests of spatial autocorrelation among mixed-effects logistic regression models 185

Modeling of symptomatic stool 186

Hazard analysis of enteric infection 187

Retesting of household and neighborhood risk factors, controlling for breastfeeding status 192

Further discussion of results from Aim 3: 198

Discussion of pathogen group-specific findings from Aim 3: 198

References 200

About this Dissertation

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research Field
Mot-clé
Committee Chair / Thesis Advisor
Committee Members
Dernière modification

Primary PDF

Supplemental Files