Hand- and Object-Mouthing of Rural Bangladeshi Children 3-18 Months Old

A multi-pathogen behavioral exposure model for young children playing in public spaces in developing communities

Diarrheal disease is the second leading cause of death among children under five in developing communities, despite active interventions to improve access to water, sanitation, and hygiene resources. Even interventions with high fidelity and compliance saw minimal improvements in health outcomes, necessitating a need for looking beyond traditionally targeted exposure pathways. This study focuses on the pathogen exposure a young child may receive while playing in the public spaces of informal settlements, where animal feces, human feces, and garbage are frequently observed. The study utilized 79 soil samples previously collected across ten cluster sites in Corail, Haiti and processed using DelAgua cultural assays and quantitative Polymerase Chain Reaction methods. Molecular assays screened for Aeromonas, Vibrio cholera, and several pathogenic Escherichia coli species. Behavioral observations of young children (<5 years old) were also conducted in overlapping areas with the environmental sampling to quantify frequency of risky and mitigating behaviors. Environmental and behavioral data were combined to obtain the posterior distribution of children's pathogen exposure from playing in a public space for one hour. The model estimated that children have a likelihood of approximately 70% of being exposed to a pathogen during one hour of play and a greater than 30% chance of being exposed to multiple pathogens in the same period. While children and toddlers practice fewer risky behaviors compared to infants, they were shown to have higher likelihood of exposure and slightly higher pathogen dose per exposure. As anticipated, a high correlation between genes from the same E. coli species was observed in the model output. These findings demonstrate the need to consider public spaces as an important exposure pathway for young children for both future research and interventions.

Addressing Fecal Contamination in Rural Kenyan Households: The Roles of Environmental Interventions and Animal Ownership

Combined water, sanitation, and handwashing (WSH) interventions could reduce fecal contamination along more transmission pathways than single interventions alone. We measured Escherichia coli levels in 3909 drinking water samples, 2691 child hand rinses, and 2422 toy ball rinses collected from households enrolled in a 2-year cluster-randomized controlled trial evaluating single and combined WSH interventions. Water treatment with chlorine reduced E. coli in drinking water. A combined WSH intervention improved water quality by the same magnitude but did not affect E. coli levels on hands or toys. One potential explanation for the limited impact of the sanitation intervention (upgraded latrines) is failure to address dog and livestock fecal contamination. Small ruminant (goat or sheep) ownership was associated with increased E. coli levels in stored water and on child hands. Cattle and poultry ownership was protective against child stunting, and domesticated animal ownership was not associated with child diarrhea. Our findings do not support restricting household animal ownership to prevent child diarrheal disease or stunting but do support calls for WSH infrastructure that can more effectively reduce household fecal contamination.

Protocol for the PATHOME study: a cohort study on urban societal development and the ecology of enteric disease transmission among infants, domestic animals and the environment

INTRODUCTION

Global morbidity from enteric infections and diarrhoea remains high in children in low-income and middle-income countries, despite significant investment over recent decades in health systems and water and sanitation infrastructure. Other types of societal development may be required to reduce disease burden. Ecological research on the influence of household and neighbourhood societal development on pathogen transmission dynamics between humans, animals and the environment could identify more effective strategies for preventing enteric infections.

METHODS AND ANALYSIS

The 'enteric pathome'-that is, the communities of viral, bacterial and parasitic pathogens transmitted from human and animal faeces through the environment is taxonomically complex in high burden settings. This integrated cohort-exposure assessment study leverages natural socioeconomic spectrums of development to study how pathome complexity is influenced by household and neighbourhood infrastructure and hygiene conditions. We are enrolling under 12-month-old children in low-income and middle-income neighbourhoods of two Kenyan cities (Nairobi and Kisumu) into a 'short-cohort' study involving repeat testing of child faeces for enteric pathogens. A mid-study exposure assessment documenting infrastructural, behavioural, spatial, climate, environmental and zoonotic factors characterises pathogen exposure pathways in household and neighbourhood settings. These data will be used to inform and validate statistical and agent-based models (ABM) that identify individual or combined intervention strategies for reducing multipathogen transmission between humans, animals and environment in urban Kenya.

ETHICS AND DISSEMINATION

The protocols for human subjects' research were approved by Institutional Review Boards at the University of Iowa (ID-202004606) and AMREF Health Africa (ID-ESRC P887/2020), and a national permit was obtained from the Kenya National Commission for Science Technology and Innovation (ID# P/21/8441). The study was registered on Clinicaltrials.gov (Identifier: NCT05322655) and is in pre-results stage. Protocols for research on animals were approved by the University of Iowa Animal Care and Use Committee (ID 0042302).

Environmental and behavioural exposure pathways associated with diarrhoea and enteric pathogen detection in 5-month-old, periurban Kenyan infants: a cross-sectional study

OBJECTIVES

The aim of this study was to test whether household environmental hygiene and behavioural conditions moderated associations between diarrhoea and enteric pathogen detection in infants 5 months of age in Kenya and pathogen sources, including latrine access, domestic animal co-habitation and public food sources.

DESIGN

Cross-sectional study utilising enrolment survey data of households participating in the Safe Start cluster-randomised controlled trial .

SETTING

Kisumu, Kenya.

PARTICIPANTS

A total of 898 caregivers with 5-month (22 week ± 1 week) aged infants were enrolled in the study and completed the enrolment survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcomes were (1) caregiver-reported 7-day diarrhoea prevalence and (2) count of types of enteric viruses, bacteria and parasites in infant stool. Exposures and effect modifiers included water access and treatment, cohabitation with domestic animals, sanitation access, handwashing practices, supplemental feeding, access to refrigeration and flooring.

RESULTS

Reported handwashing after handling animals (adjusted odds ratio (aOR)=0.20; 95% CI=0.06 to 0.50) and before eating (aOR=0.44; 95% CI=0.26 to 0.73) were strongly associated with lower risk of caregiver-reported diarrhoea, while cohabitation with animals (aOR=1.54; 95% CI=1.01 to 2.34) living in a household with vinyl-covered dirt floors (aOR=0.60; 95% CI=0.45 to 0.87) were strongly associated with pathogen codetection in infants. Caregiver handwashing after child (p=0.02) or self-defecation (p=0.03) moderated the relationship between shared sanitation access and infant exposure to pathogens, specifically private latrine access was protective against pathogen exposure of infants in households, where caregivers washed hands after defecation. In the absence of handwashing, access to private sanitation posed no benefits over shared latrines for protecting infants from exposure.

CONCLUSION

Our evidence highlights eliminating animal cohabitation and improving flooring, postdefecation and food-related handwashing, and safety and use of cow milk sources as interventions to prevent enteric pathogen exposure of young infants in Kenya.

TRIAL REGISTRATION NUMBER

NCT03468114.

Heavy metal ecological-health risk assessment under wheat-maize rotation system in a high geological background area in eastern China

A high geological background can increase the ecological and health risks associated with crop production; therefore, it is essential to assess the heavy metals and their impact. In this study, ecological and health risk impacts of heavy metal contamination, in combination with positive matrix factorization was assessed for an area with high geological background with wheat-maize cropping system, to provide a quantitative understanding of the effects of heavy metals, enabling its prevention and control. This study revealed that the comprehensive ecological risk (RI_wheat-maize) is 56.21 (low), with industries being the biggest contributors (34.22%). Comprehensive health risk (non-carcinogenic) assessment showed that industrial (40.98-49.30%) and natural (23.96-37.64%) factors were the primary (particularly of Cd and Zn) and secondary (particularly of Cr and Ni) contributors, respectively in eastern China. Comprehensive health risk (HI_wheat-maize) for children and adults were 0.74 and 0.42, respectively, indicating that non-carcinogenic risks were at an acceptable level. Soil ingestion was the primary pathway for health risks (62.23-73.00%), especially for children. Based on soil heavy metal sources and crop systems, source-ecological risk assessment and source-health risk assessment were used to provided valuable insights on making strategies to protect human health in high geological background areas.

Hand-to-Face Contact of Preschoolers during Indoor Activities in Childcare Facilities in the Republic of Korea

PURPOSE

This study aimed to characterize hand-to-face contact (HFC) in children and analyze the factors that affect HFC behaviors of preschoolers in childcare facilities in Korea.

METHODS

Thirty preschoolers aged between 13 and 84 months were enrolled with parents' voluntary participation. Videotaping (10 children/childcare center/2 h) and video reading was performed from 23 November 2018 to 7 January 2019.

RESULTS

A total of 2719 cases of HFC were observed in 30 participants within 2 h. The average contact with the facial mucosa (frequency/person/2 h) was 55.6 ± 42.2, of which the mouth (25.4 ± 23.9), the nose (20.4 ± 24.5), and the eye (9.8 ± 11.7) were the most frequent contacts, in that order. The average contact duration (sec/person/2 h) with the facial mucosa was 232.6 ± 169.7, of which the mouth (145.2 ± 150), the nose (57.6 ± 62.2), and the eyes (29.7 ± 42.3) were the longest in that order. The density distribution of the frequency and duration of mucosal contact was wider in boys than in girls. The mucosal and non-mucosal contact frequencies were significantly higher in boys (p = 0.027 and p = 0.030, respectively).

CONCLUSION

Children's HFC frequency and duration were highest for the mouth, nose, and eyes. Boys tended to have a higher contact frequency than girls for both mucous and non-mucous HFC.

Global practices, geographic variation, and determinants of child feces disposal in 42 low- and middle-income countries: An analysis of standardized cross-sectional national surveys from 2016 - 2020

Background

Despite considerable progress improving water and sanitation access globally, unsafe child feces disposal remains common in many low- and middle-income countries (LMICs), posing an important health risk. The present study characterizes the current prevalence of child feces disposal practices and child latrine use across low- and middle-income countries and investigates determinants associated with appropriate disposal practices.

Methods

Data for children ranging from 0 through 4 years of age were analyzed from standardized and nationally-representative surveys of 42 LMICs collected from 2016 to 2020 to assess child feces disposal practices. We report child feces disposal in three categories: disposal in any type of latrine, disposal in an improved latrine, and disposal through means other than in a latrine. Survey weighted multiple Poisson regression models were used to explore factors associated with these practices.

Results

Data on 403,036 children (weighted N = 191 million) demonstrated that a minority (40.3%) of children have their feces disposed of in a latrine of any kind, and just 29% have feces disposed of in an improved latrine. Prevalence varied considerably by country and region. In adjusted analyses, both child feces disposal in any latrine and disposal in an improved latrine increased with child age, higher intra-country relative wealth, and urban living, and decreased with breastfeeding and shared sanitation facilities. Disposal in improved latrines additionally increased with access to higher levels of service for drinking water and higher mother's education. Nevertheless, the role of facility access alone was insufficient, as only about half of children with household access to any latrine or improved latrines had their feces disposed of in these facilities. Child latrine use among households with latrine access was also low and highly variable across countries.

Conclusions

Children's feces in LMICs are infrequently disposed of in any latrine type, and even less frequently in improved latrines. In order to minimize health risks in LMICs, increased effort must be undertaken not just to increase sanitation coverage but to address these common barriers to safe child feces disposal and child latrine use.

•

Global child feces disposal in latrines is low and variable between countries.

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Latrine access is insufficient to explain low use for child feces management.

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Household relative wealth is associated with increased disposal in latrines.

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Child latrine use increases with age but remains low and varied between countries.

Exploring the determinants and indicators of poultry feces management behaviors in rural Western Uganda

Animal ownership has reported financial and nutritional benefits but has also been associated with enteric and respiratory infections, and inadequate sanitation and hygiene can lead to children touching and ingesting animal fecal matter. We identified key indicators for poultry feces management and investigated their social determinants using data from a baseline survey of a randomized-controlled trial of a poultry management training program in rural Western Uganda. The baseline survey was conducted in the Masindi and Kiryandongo districts of Uganda in September 2019, and data collected from 609 households were used. We evaluated indicators for poultry feces management behaviors using scale development methods, including descriptive statistics, bivariate correlation analyses, and Factor Analysis of Mixed Data. We also investigated social determinants of key poultry feces management behaviors using logistic and multinomial logistic regression models. A significant increase in odds of having free-roaming poultry was found for each additional poultry owned (OR = 1.18, P < 0.001). The odds of a household having an observed enclosure for poultry increased by 5% with each incremental poultry owned (OR = 1.05, P < 0.001), and by 4% with increasing wealth with each additional point on the poverty probability index score (OR = 1.04, P < 0.001). Our results also suggest enclosures are intermittently used and constructing them without further intervention likely will not be sufficient for effectively managing animal fecal contamination. We recommend that future studies on animal feces management measure indicators for corralling and feces disposal practices and evaluate their relationship to enteric pathogen exposure and health outcomes. Insights from this work can inform the development of robust indicators of poultry feces management behaviors that can be used for monitoring and evaluation purposes.

Characterizing Behaviors Associated with Enteric Pathogen Exposure among Infants in Rural Ecuador through Structured Observations

The relative importance of environmental pathways that results in enteropathogen transmission may vary by context. However, measurement of contact events between individuals and the environment remains a challenge, especially for infants and young children who may use their mouth and hands to explore their environment. Using a mixed-method approach, we combined 1) semistructured observations to characterize key behaviors associated with enteric pathogen exposure and 2) structured observations using Livetrak, a customized software application, to quantify the frequency and duration of contacts events among infants in rural Ecuador. After developing and iteratively piloting the structured observation instrument, we loaded the final list of prompts onto a LiveTrak pallet to assess environmental exposures of 6-month infants (N = 19) enrolled in a prospective cohort study of diarrheal disease. Here we provide a detailed account of the lessons learned. For example, in our field site, 1) most mothers reported washing their hands after diaper changes (14/18, 77.8%); however only a third (4/11, 36.4%) were observed washing their hands; 2) the observers noted that animal ownership differed from observed animal exposure because animals owned by neighboring households were reported during the observation; and 3) using Livetrak, we found that infants frequently mouthed their hands (median = 1.9 episodes/hour, median duration: 1.6 min) and mouthed surroundings objects (1.8 episodes/hour, 1.9 min). Structured observations that track events in real time, can complement environmental sampling, quantitative survey data and qualitative interviews. Customizing these observations enabled us to quantify enteric exposures most relevant to our rural Ecuadorian context.

Hygiene in early childhood development centres in low-income areas of Blantyre, Malawi

Diarrhoeal disease remains a leading cause of death in children in sub-Saharan Africa, attributed to environmental health factors such as inadequate water, sanitation and hygiene (WASH) and food hygiene. This formative study in low-income areas of Blantyre focussed on the practices in Early Childhood Development Centre (ECDCs) environments where children spend a significant amount of time. A mixed-methods approach was applied to identify key hygiene behaviours in ECDCs through; checklist and structured observations (n = 849 children; n = 33 caregivers), focus group discussions (n = 25) and microbiological sampling (n = 261) of drinking water, food handler's hands, and eating utensils. ECDCs had inadequate WASH infrastructure; coupled with poor hygiene practices and unhygienic environments increased the risk of faecal-oral disease transmission. Presence of E. coli in drinking water confirmed observed poor water handling habits by staff and children. Addressing undesired hygiene practices in ECDCs has the potential to improve the health outcomes of children in low-income settings.

Associations between ambient fine particulate matter and child respiratory infection: The role of particulate matter source composition in Dhaka, Bangladesh

Air pollution in the form of fine particulate matter (PM_2.5) has been linked to adverse respiratory outcomes in children. However, the magnitude of this association in South Asia and sources of PM_2.5 that drive adverse health effects are largely unknown. This study evaluates associations between short-term variation in ambient PM_2.5 and incidence of pneumonia and upper respiratory infections among children in Dhaka, Bangladesh. We also perform an exploratory analysis of the PM_2.5 source composition that is most strongly associated with health endpoints. We leveraged data from health surveillance of children less than five years of age between 2005 and 2014 in Kamalapur, Bangladesh, including daily physician-confirmed diagnoses of pneumonia and upper respiratory infection. Twice-weekly source-apportioned ambient PM_2.5 measurements were obtained for the same period, and Poisson regression adjusted for time-varying covariates was used to estimate lagged associations between ambient PM_2.5 and respiratory infection. We use complementary matching and stratification approaches to evaluate whether these associations vary across PM_2.5 source composition. Total PM_2.5 mass was associated with a modest increase in incidence of pneumonia, with a peak effect size two days after exposure (rate ratio = 1.032; 95% confidence interval = 1.008-1.056). We did not identify a significant association between PM_2.5 and upper respiratory infection. Stratified and matching analyses suggested this association was stronger among days when ambient PM_2.5 had a higher mass percent associated with brick kiln and fugitive lead emissions.: This study suggests that elevated ambient PM_2.5 contributes to increased incidence of child pneumonia in urban Dhaka, and that this relationship varies among days with different source composition of PM_2.5.

Quantified Activity Patterns for Young Children in Beach Environments Relevant for Exposure to Contaminants

In a study to evaluate beach play activities, 120 children were videotaped to observe and quantify factors that could influence their exposure to contaminants in the beach environment. Children aged 1 to 6 years were followed by researchers with video cameras at beaches (two in Miami, Florida and two in Galveston, Texas) for approximately one hour each. Factors evaluated included time spent in various beach locations, various activities engaged in, and various surfaces contacted (including contacts by hand and mouth). Activities recorded in the videos were transcribed to text files to allow for quantitative analyses. Across all sexes, age groups, and beaches, Wading was the most common activity and Seawater was the most common location where children played. The left hand was found to not be in contact with objects most of the time, while the right hand, considered the most dominant hand in most cases, contacted Plastic-Toys the most. Although activity patterns collection through videotaping and videotranslation can be labor-intensive, once collected, they can be widely useful for estimates of exposures to all contaminants in the beach environment (e.g., microorganisms and chemicals) as well as UV exposure, with considerations for whether the contaminants are found in water, sand or both. These activity patterns were collected to potentially look at exposures following the Deepwater Horizon 2010 Spill.

A One Health Approach to Child Stunting: Evidence and Research Agenda

Stunting (low height for age) affects approximately one-quarter of children aged < 5 years worldwide. Given the limited impact of current interventions for stunting, new multisectoral evidence-based approaches are needed to decrease the burden of stunting in low- and middle-income countries (LMICs). Recognizing that the health of people, animals, and the environment are connected, we present the rationale and research agenda for considering a One Health approach to child stunting. We contend that a One Health strategy may uncover new approaches to tackling child stunting by addressing several interdependent factors that prevent children from thriving in LMICs, and that coordinated interventions among human health, animal health, and environmental health sectors may have a synergistic effect in stunting reduction.

Household finished flooring and soil-transmitted helminth and Giardia infections among children in rural Bangladesh and Kenya: a prospective cohort study

BACKGROUND

Soil-transmitted helminths and Giardia duodenalis are responsible for a large burden of disease globally. In low-resource settings, household finished floors (eg, concrete floors) might reduce transmission of soil-transmitted helminths and G duodenalis.

METHODS

In a prospective cohort of children nested within two randomised trials in rural Bangladesh and Kenya, we estimated associations between household finished flooring and soil-transmitted helminths and G duodenalis prevalence. In 2015-16, we collected stool samples from children aged 2-16 years in rural Bangladesh and Kenya. We detected soil-transmitted helminth infection using quantitative PCR (qPCR; Bangladesh n=2800; Kenya n=3094), and G duodenalis using qPCR in Bangladesh (n=6894) and ELISA in Kenya (n=8899). We estimated adjusted prevalence ratios (aPRs) using log-linear models adjusted for potential confounders.

FINDINGS

7187 (92·2%) of 7795 children in Bangladesh and 9077 (93·7%) of 9686 children in Kenya provided stool specimens that were analysed by qPCR. At enrolment, 691 (10%) households in Bangladesh and 471 (5%) households in Kenya had finished floors. In both countries, household finished flooring was associated with lower Ascaris lumbricoides prevalence (Bangladesh aPR 0·33, 95% CI 0·14-0·78; Kenya 0·62, 0·39-0·98) and any soil-transmitted helminths (Bangladesh 0·73, 0·52-1·01; Kenya 0·57, 0·37-0·88). Household finished floors were also associated with lower Necator americanus prevalence in Bangladesh (0·52, 0·29-0·94) and G duodenalis prevalence in both countries (Bangladesh 0·78, 0·64-0·95; Kenya 0·82, 0·70-0·97).

INTERPRETATION

In low-resource settings, living in households with finished floors over a 2-year period was associated with lower prevalence of G duodenalis and some soil-transmitted helminths in children.

FUNDING

Bill & Melinda Gates Foundation and Task Force for Global Health.

Soil ingestion among young children in rural Bangladesh

Ingestion of soil and dust is a pathway of children's exposure to several environmental contaminants, including lead, pesticides, and fecal contamination. Empirically based estimates of central tendency for soil consumption by children in high-income countries range from 9 to 135 dry mg/day. Using a Monte Carlo simulation, we modeled the mass of soil directly and indirectly ingested per day by rural Bangladeshi children and identified the parameters that influence the mass ingested. We combined data from observations of direct and indirect ingestion among children with measurements of soil mass on the children's hands, mother's hands, and objects to quantify soil ingestion/day. Estimated geometric mean soil ingestion was 162 dry mg/day for children 3-5 months, 224 dry mg/day for children 6-11 months, 234 dry mg/day for children 12-23 months, 168 dry mg/day for children 24-35 months, and 178 dry mg/day for children 36-47 months old. Across all age groups, children placing their hands in their mouths accounted for 46-78% of total ingestion and mouthing objects contributed 8-12%. Direct ingestion of soil accounted for nearly 40% of soil ingested among children 6-23 months old. Sensitivity analyses identified that the parameters most affecting the estimates were the load of soil on the child's hand, the frequency of hand-to-mouth contacts while not eating, and, for children 6-23 months old, the frequency of direct soil ingestion. In a rural, low-income setting, children's soil consumption was substantially more than the estimates for children in high-income countries. Further characterizing soil ingestion of children in low-income contexts would improve assessments of the risks they face from soil-associated contaminants.

Shared bacterial communities between soil, stored drinking water, and hands in rural Bangladeshi households

Understanding household-level transmission pathways of fecal pathogens can provide insight for developing effective strategies to reduce diarrheal illness in low- and middle-income countries. We applied whole bacterial community analysis to investigate pathways of bacterial transmission in 50 rural Bangladeshi households. SourceTracker was used to quantify the shared microbial community in household reservoirs (stored drinking water, soil, and hands) and estimate the percentage of fecal-associated bacteria from child and mothers' feces in these reservoirs. Among the reservoirs studied, most bacterial transfer occurred between mothers' and children's hands and between mothers' hands and stored water. The relative percentage of human fecal-associated bacteria in all household reservoirs was low. We also quantified the number of identical amplicon sequence variants within and between individual households to assess bacterial community exchange in the domestic environment. Intra-household sharing of bacteria between mothers' and children's hands and between hands and soil was significantly greater than inter-household sharing.

Ingestion of Fecal Bacteria along Multiple Pathways by Young Children in Rural Bangladesh Participating in a Cluster-Randomized Trial of Water, Sanitation, and Hygiene Interventions (WASH Benefits)

Quantifying the contribution of individual exposure pathways to a child's total ingestion of fecal matter could help prioritize interventions to reduce environmental enteropathy and diarrhea. This study used data on fecal contamination of drinking water, food, soil, hands, and objects and second-by-second data on children's contacts with these environmental reservoirs in rural Bangladesh to assess the relative contribution of different pathways to children's ingestion of fecal indicator bacteria and if ingestion decreased with the water, sanitation, and hygiene interventions implemented in the WASH Benefits Trial. Our model estimated that rural Bangladeshi children <36 months old consume 3.6-4.9 log₁₀ most probable number E. coli/day. Among children <6 months, placing objects in the mouth accounted for 60% of E. coli ingested. For children 6-35 months old, mouthing their own hands, direct soil ingestion, and ingestion of contaminated food were the primary pathways of E. coli ingestion. The amount of E. coli ingested by children and the predominant pathways of E. coli ingestion were unchanged by the water, sanitation, and hygiene interventions. These results highlight contaminated soil, children's hands, food, and objects as primary pathways of E. coli ingestion and emphasize the value of intervening along these pathways.

Measuring Environmental Exposure to Enteric Pathogens in Low-Income Settings: Review and Recommendations of an Interdisciplinary Working Group

Infections with enteric pathogens impose a heavy disease burden, especially among young children in low-income countries. Recent findings from randomized controlled trials of water, sanitation, and hygiene interventions have raised questions about current methods for assessing environmental exposure to enteric pathogens. Approaches for estimating sources and doses of exposure suffer from a number of shortcomings, including reliance on imperfect indicators of fecal contamination instead of actual pathogens and estimating exposure indirectly from imprecise measurements of pathogens in the environment and human interaction therewith. These shortcomings limit the potential for effective surveillance of exposures, identification of important sources and modes of transmission, and evaluation of the effectiveness of interventions. In this review, we summarize current and emerging approaches used to characterize enteric pathogen hazards in different environmental media as well as human interaction with those media (external measures of exposure), and review methods that measure human infection with enteric pathogens as a proxy for past exposure (internal measures of exposure). We draw from lessons learned in other areas of environmental health to highlight how external and internal measures of exposure can be used to more comprehensively assess exposure. We conclude by recommending strategies for advancing enteric pathogen exposure assessments.

Association of nutrition, water, sanitation and hygiene practices with children's nutritional status, intestinal parasitic infections and diarrhoea in rural Nepal: a cross-sectional study

Background

Providing universal access to safe water, sanitation and hygiene (WASH) in remote Nepal remains challenging. We investigated WASH conditions and their association with children’s nutritional status, intestinal parasitic infections and diarrhoea.

Methods

Data was collected through a cross-sectional survey of 1427 households, including questionnaires, observations, stool analysis, anthropometry, water quality measurements, and assessment of clinical signs of nutritional deficiencies.

Results

We found 55.5% of children were undernourished, 63.9% had clinical signs of nutritional deficiencies, 51.1% had intestinal parasitic infections and 52.2% had diarrhoea. Multivariate mixed logistic regression analysis revealed a statistically significant negative association between undernutrition and socio-economic level, with adjusted odds ratios (AOR) of 0.70 (95%-CI = 0.43–1.11) and 0.43 (95%-CI = 0.25–0.75) for high and intermediate levels compared to the lowest level. Undernutrition was negatively associated with regular deworming of children (AOR = 0.44, 95% CI = 0.20–0.94), food supplements (AOR = 0.57, 95% CI = 0.38–0.84), household’s own food production (AOR = 0.67, 95% CI = 0.46–0.97) and personal hygiene (AOR = 0.83, 95% CI = 0.51–1.35). Nutritional deficiency was negatively associated with handwashing after cleaning a baby’s bottom (AOR = 0.60, 95% CI = 0.40–0.92) and cleanliness of caregiver’s hands (AOR = 0.61, 95% CI = 0.41–0.89) and positively associated with keeping animals inside the house overnight (AOR = 1.71, 95% CI = 1.17–2.51) and the presence of total coliforms in the drinking water source (AOR = 10.44, 95% CI = 1.61–67.4). Diarrhoea was positively associated with intermittent water supply (AOR = 2.72, 95% CI = 1.18–6.31) and the presence of a mud floor (AOR = 2.29, 95% CI = 1.20–4.37) and negatively associated with cleanliness of the toilet (AOR = 0.68, 95% CI = 0.47–0.98), and the cleanliness of children’s hands (AOR = 0.62, 95% CI = 0.40–0.96).

Conclusions

Our study found, more than half of the survey children were in a critical health condition. Results suggest that child health improvements are dependent on multiple public health improvements, including providing better nutrition, promoting adequate hygiene behaviour, such as handwashing, keeping the latrines clean, keeping the household environment free from animal faeces and assuring a reliable supply of safe water.

Toddler behavior, the home environment, and flame retardant exposure

Toddlers are at increased risk of dust ingestion and subsequently flame retardant (FR) exposure because they often play close to the floor and mouth hands and objects. Exposure to some FRs have been associated to endocrine disruption and neurodevelopmental disorders. Previous research has shown higher FR concentrations in toddlers' serum and urine, but which toddler-behaviors influence exposure levels remains to be determined. We investigated how toddler-behaviors are associated to FRs in hand wipes (HWs) and saliva. Fifty 8-18 month-old children from the Linking EDCs in maternal Nutrition to Child health study, were visited at home. The child's behavior was observed and assessed using a questionnaire. Hand-to-object behavior frequency was associated with HW tris(chloroethyl) phosphate (TCEP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), tris(phenyl) phosphate, tris(methylphenyl) phosphate, and resorcinol bis(diphenyl phosphate) levels above the detection limit. Children playing with electronics multiple times per week had higher TDCIPP HW levels compared to children playing with electronics once per month or never (p = 0.032 and p = 0.046). Frequent mouth-to-object and frequent mouthing a pacifier were associated with lower TDCIPP (p = 0.019) and tris(2-chloroisopropyl) phosphate (TCIPP) HW levels, respectively (p = 0.002-0.019). Exposure estimates based on hand-to-mouth behavior did not exceed the available reference doses. This is the first study investigating toddler-behavior in relation to FR hand loadings. Although a range of behaviors was investigated, only a few showed a relation with FR HW levels, suggesting that toddler-behavior might not alone be responsible for the elevated FR levels in children. It is therefore important to explore other pathways including dermal absorption and inhalation.

Child defecation and feces management practices in rural Bangladesh: Associations with fecal contamination, observed hand cleanliness and child diarrhea

Child open defecation is common in low-income countries and can lead to fecal exposure in the domestic environment. We assessed associations between child feces management practices vs. measures of contamination and child diarrhea among households with children <5 years in rural Bangladesh. We visited 360 households quarterly and recorded caregiver-reported diarrhea prevalence, and defecation and feces disposal practices for children <5 years. We examined caregiver and child hands for visible dirt and enumerated E. coli in child and caregiver hand rinse and stored drinking water samples. Safe child defecation (in latrine/potty) and safe feces disposal (in latrine) was reported by 21% and 23% of households, respectively. Controlling for potential confounders, households reporting unsafe child defecation had higher E. coli prevalence on child hands (prevalence ratio [PR] = 1.12, 1.04-1.20) and in stored water (PR = 1.12,1.03-1.21). Similarly, households reporting unsafe feces disposal had higher E. coli prevalence on child hands (PR = 1.11, 1.02-1.21) and in stored water (PR = 1.10, 1.03-1.18). Effects on E. coli levels were similar. Children in households with unsafe defecation and feces disposal had higher diarrhea prevalence but the associations were not statistically significant. Our findings suggest that unsafe child feces management may present a source of fecal exposure for young children.

Unsafe child feces disposal status in Ethiopia: what factors matter? Analysis of pooled data from four demographic and health surveys

Background

The only safest way to dispose of a child’s feces is to help the child use a toilet or, for very young children, to put or rinse their feces into a toilet, whereas other methods are considered unsafe. This study aimed to determine the magnitude and factors associated with unsafe child feces disposal in Ethiopia.

Methods

This was a cross-sectional study using pooled data from the four rounds of Demographic and Health Surveys (DHS) conducted in Ethiopia (2000, 2005, 2011, and 2016). Data on child feces disposal practice was collected for all children born during the 5 years preceding survey. Mothers were asked for the youngest child born, “The last time child passed stools, what was done to dispose of the stools?”.Descriptive statistics were computed to illustrate the given data. Multivariable logistic regression was performed to identify factors associated with unsafe child feces disposal.

Results

The pooled dataset contains data for 40,520 children younger than 5 years, male accounts 20,629 (50.9%). Overall, 77.7% (95%CI: 76.3–79.0) of children feces disposed of unsafely. In the multivariable logistic regression model, those mothers whose child was 13–24 months [AOR: 0.68, 95% CI: (0.60–0.78)] and ≥ 25 months [AOR: 0.66, 95% CI: (0.60–0.72)] were lower odds of unsafe child’s feces disposal. Children born into households having two or fewer children were 33% lower [AOR: 0.67, 95% CI: (0.56–0.79)] odds of unsafe child’s feces disposal than their counterparts. The odds of disposing of feces unsafely among households having improved toilet facility was 76% lower [AOR: 0.24, 95% CI: (0.19–0.29)] that of households lacking such facilities. Further, being an urban resident, having improved drinking water facility, a high level of maternal and paternal education, paternal occupational status (work in non-agriculture), and maternal age (25–34 and ≥ 35 years) were factors that associated with lower odds of unsafe child’s feces disposal.

Conclusions

Three in four Ethiopian children feces disposed of unsafely. Household and socio-demographic factors, such as access to improved toilet facility, the child’s age (older age), and both higher maternal and paternal education levels were important factors that significantly associated with lower odds of unsafe child feces disposal.

The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoea

Child stunting is a global problem and is only modestly responsive to dietary interventions. Numerous observational studies have shown that water quality, sanitation, and handwashing (WASH) in a household are strongly associated with linear growth of children living in the same household. We have completed three randomised efficacy trials testing improved household-level WASH with and without improved infant and young child feeding (IYCF) on stunting and diarrhoea in Bangladesh, Kenya, and Zimbabwe. In all trials, improved IYCF had a statistically significant benefit, but WASH had no effect on linear growth. In observational analyses of data from the control groups of the three trials, baseline sanitation was a strong risk factor for stunting in the study populations, suggesting this frequently reported association might be confounded by unmeasured factors of household wellbeing. WASH interventions reduced diarrhoea in Bangladesh, but not in Kenya or Zimbabwe. Intervention promoters visited participants six times per month in Bangladesh compared with monthly in Kenya and Zimbabwe; a review of the literature shows that virtually all published studies that have reported an effect on diarrhoea through home-based water treatment and handwashing promotion achieved high adherence by visiting participants at daily to fortnightly intervals. Despite achieving substantial behavioural change and significant reduction in infection prevalence for some enteric pathogens, detection of enteropathogens among children in the WASH groups of the trials was typically at ten times higher prevalence compared with high-income countries. Considering these results, we recommend that future research in the WASH sector focus on developing and evaluating interventions that are radically more effective in reducing faecal contamination in the domestic environment than the interventions implemented in these trials.

Health Outcomes of an Integrated Behaviour-Centred Water, Sanitation, Hygiene and Food Safety Intervention-A Randomised before and after Trial

Diarrhoeal disease in children under five in low income settings has been associated with multiple environmental exposure pathways, including complementary foods. Conducted from February to December 2018 in rural Malawi, this before and after trial with a control used diarrhoeal disease as a primary outcome, to measure the impact of a food hygiene intervention (food hygiene + handwashing) relative to a food hygiene and water, sanitation and hygiene (WASH) intervention (food hygiene + handwashing + faeces management + water management). The 31-week intervention was delivered by community-based coordinators through community events (n = 2), cluster group meetings (n = 17) and household visits (n = 14). Diarrhoeal disease was self-reported and measured through an end line survey, and daily diaries completed by caregivers. Difference-in-differences results show a 13-percentage point reduction in self-reported diarrhoea compared to the control group. There were also significant increases in the presence of proxy measures in each of the treatment groups (e.g., the presence of soap). We conclude that food hygiene interventions (including hand washing with soap) can significantly reduce diarrhoeal disease prevalence in children under five years in a low-income setting. Therefore, the promotion of food hygiene practices using a behaviour-centred approach should be embedded in nutrition and WASH policies and programming.

Effect of Sanitation Improvements on Pathogens and Microbial Source Tracking Markers in the Rural Bangladeshi Household Environment

Diarrheal illnesses from enteric pathogens are a leading cause of death in children under five in low- and middle-income countries (LMICs). Sanitation is one way to reduce the spread of enteric pathogens in the environment; however, few studies have investigated the effectiveness of sanitation in rural LMICs in reducing pathogens in the environment. In this study, we measured the impact of a sanitation intervention (dual-pit latrines, sani-scoops, child potties delivered as part of a randomized control trial, WASH Benefits) in rural Bangladeshi household compounds by assessing prevalence ratios, differences, and changes in the concentration of pathogen genes and host-specific fecal markers. We found no difference in the prevalence of pathogenic Escherichia coli, norovirus, or Giardia genes in the domestic environment in the sanitation and control arms. The prevalence of the human fecal marker was lower on child hands and the concentration of animal fecal marker was lower on mother hands in the sanitation arm in adjusted models, but these associations were not significant after correcting for multiple comparisons. In the subset of households with ≥10 individuals per compound, the prevalence of enterotoxigenic E. coli genes on child hands was lower in the sanitation arm. Incomplete removal of child and animal feces or the compound (versus community-wide) scale of intervention could explain the limited impacts of improved sanitation.

Child feces management practices and fecal contamination: A cross-sectional study in rural Odisha, India

Safe child feces management (CFM) is likely critical for reducing exposure to fecal pathogens in and around the home, but the effectiveness of different CFM practices in reducing fecal contamination is not well understood. We conducted a cross-sectional study of households with children <6 years in rural Odisha, India, using household surveys (188 households), environmental sample analysis (373 samples for 80 child defecation events), and unstructured observation (33 households) to characterize practices and measure fecal contamination resulting from CFM-related practices, including defecation, feces handling and disposal, defecation area or tool cleaning, anal cleansing, and handwashing. For environmental sampling, we developed a sampling strategy that involved collecting samples at the time and place of child defecation to capture activity-level fecal contamination for CFM practices. Defecating on the floor or ground, which was practiced by 63.7% of children <6 years, was found to increase E. coli contamination on finished floors (p < 0.001) or earthen ground surfaces (p = 0.008) after feces were removed, even if paper was laid down prior to defecation. Use of unsafe tools (e.g., paper, plastic bag, straw/hay) to pick up child feces increased E. coli contamination on caregiver hands after feces handling (p < 0.0001), whereas the use of safe tools (e.g., potty, hoe, scoop) did not increase hand contamination. Points of contamination from cleaning CFM hardware and anal cleansing were also identified. The most common disposal location for feces of children <6 years was to throw feces into an open field (41.6%), with only 32.3% disposed in a latrine. Several households owned scoops or potties, but use was low and we identified shortcomings of these CFM tools and proposed alternative interventions that may be more effective. Overall, our results demonstrate the need for CFM interventions that move beyond focusing solely on feces disposal to address CFM as a holistic set of practices.

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

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.

Exposure to Livestock Feces and Water Quality, Sanitation, and Hygiene (WASH) Conditions among Caregivers and Young Children: Formative Research in Rural Burkina Faso

Livestock farming is common in low-income settings as a source of income and animal-sourced food. However, there is growing evidence of the harmful health effects of proximity of animals to infants and young children, especially through exposure to zoonotic pathogens. Poultry ownership is almost universal in rural Burkina Faso. Poultry feces are a significant risk factor for enteric diseases that are associated with child undernutrition. To investigate the extent of exposure to livestock feces among young children and caregivers, we conducted direct observations of 20 caregiver-child dyads for a total of 80 hours (4 hours per dyad) and recorded water quality, sanitation, and hygiene (WASH)-related behaviors. We also undertook in-depth interviews with these caregivers and focus group discussions with separate groups of men and women who were poultry farmers. Poultry and other livestock feces were visible in all 20 and 19 households, respectively, in both kitchen areas and in the household courtyards where children frequently sit or crawl. Direct soil ingestion by young children was observed in almost half of the households (45%). Poor handwashing practices were also common among caregivers and children. Although latrines were available in almost all households, child feces disposal practices were inadequate. This body of research suggests an urgent need to adapt conventional WASH and livestock interventions to reduce the exposure of infants and young children to livestock feces.

Age-related changes to environmental exposure: variation in the frequency that young children place hands and objects in their mouths

Children are exposed to environmental contaminants through direct ingestion of water, food, soil, and feces, and through indirect ingestion owing to mouthing hands and objects. We quantified ingestion among 30 rural Bangladeshi children < 4 years old, recording every item touched or mouthed during 6-hour video observations that occurred annually for 3 years. We calculated the frequency and duration of mouthing and the prevalence of mouth contacts with soil and feces. We compared the mouthing frequency distributions to those from US children to evaluate the appropriateness of applying the US data to the Bangladeshi context. Median hand-mouthing frequency was 43-72 times/h and object-mouthing frequency 17-34 times/h among the five age groups assessed. For half of the observations, > 75% of all hand mouthing was associated with eating. The frequency of indoor hand mouthing not related to eating was similar to the frequency of all indoor hand mouthing among children in the United States. Object-mouthing frequency was higher among Bangladeshi children compared with US children. There was low intra-child correlation of mouthing frequencies over our longitudinal visits. Our results suggest that children's hand- and object-mouthing vary by geography and culture and that future exposure assessments can be cross-sectional if the goal is to estimate population-level distributions of mouthing frequencies. Of all observations, a child consumed soil in 23% and feces in 1%.

Do domestic animals contribute to bacterial contamination of infant transmission pathways? Formative evidence from Ethiopia

Child stunting is associated with poor water, sanitation and hygiene (WASH), partly due to the effect of infection on intestinal nutrient absorption. WASH interventions, however, show little effect on growth. A hypothesis is that bacterial contamination of hands and floors from domestic animals and their faeces, and subsequent ingestion via infant hand-to-mouth behaviours, may explain this. This formative study used microbial testing and survey and observational data from 20 households in Ethiopia to characterise principle bacterial transmission pathways to infants, considering WASH facilities and practices, infant behaviours and animal exposure. Microbial swabbing showed the contamination of hands and floor surfaces from thermotolerant coliform bacteria. Animal husbandry practices, such as keeping animals inside, contributed significantly (all p < 0.005). There was no evidence that latrine facilities mitigated contamination across infant (p = 0.76) or maternal (p = 0.86) hands or floor surfaces (p = 0.36). This small study contributes to the evidence that animal faeces are an important source of domestic bacterial contamination. The results imply that interventions aiming to reduce pathogen transmission to infants should think beyond improving WASH and also consider the need to separate infants and animals in the home. Intervention studies will be required to determine whether this reduces infant infection and improves linear growth.

Microbiological contamination of young children's hands in rural Bangladesh: Associations with child age and observed hand cleanliness as proxy

Background

Hands are a route of transmission for fecal-oral pathogens. This analysis aimed to assess associations between hand E. coli contamination and child age and determine if observed hand cleanliness can serve as a proxy for E. coli contamination on young children’s hands.

Methods

Trained field workers collected hand rinse samples from children aged 1–14 months in 584 households in rural Bangladesh and assessed the visual cleanliness of child hands (fingernails, finger pads and palms). Samples were analyzed using the IDEXX most probable number (MPN) methodto enumerate E. coli. We assessed if child age (immobile children aged 1–4 months vs. mobile children aged 5–14 months) is associated with log₁₀E. coli counts on hands using generalized estimating equations (GEE). We estimated the log₁₀ difference in hand E. coli counts associated with the cleanliness of different hand parts using a multivariable GEE model.We calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for dirty fingernails, fingerpads, palms and overall hands (the three observed parts combined) against binary E. coli presence on hands.

Results

E. coli was detected on 43% of child hands. Children in the mobile age range had 0.17 log₁₀ MPN higher E. coli on hands than those in the immobile age range (Δlog₁₀ = 0.17, 95% CI = 0.02, 0.32, p = 0.03). Children with visible dirt particles on finger pads had 0.46 log₁₀ MPN higher E. coli on hands than those with clean finger pads (Δlog₁₀ = 0.46, 95% CI = 0.05, 0.87, p = 0.03). Dirty fingernails indicated binary E. coli presence with 81% sensitivity and 26% specificity while dirty fingerpads and palms indicated E. coli presence with 29% sensitivity and 75–77% specificity. The PPV was 45–48% and NPV 59–65% for all three types of observations.

Conclusion

Hand contamination with E. coli was prevalent among young children in rural Bangladesh, with higher levels of contamination among mobile children. Studies should assess if strategies to remove animal feces from the courtyard, provide designated hygienic play spaces for children and deliver targeted messaging to mothers to wipe or wash children’s hands after contact with animals and animal feces reduce child hand contamination. Visible hand cleanliness was a poor predictor of E. coli presence on young children’s hands so other low-cost field measurements are needed to accurately detect fecal contamination on hands.

The implications of three major new trials for the effect of water, sanitation and hygiene on childhood diarrhea and stunting: a consensus statement

BACKGROUND

Three large new trials of unprecedented scale and cost, which included novel factorial designs, have found no effect of basic water, sanitation and hygiene (WASH) interventions on childhood stunting, and only mixed effects on childhood diarrhea. Arriving at the inception of the United Nations' Sustainable Development Goals, and the bold new target of safely managed water, sanitation and hygiene for all by 2030, these results warrant the attention of researchers, policy-makers and practitioners.

MAIN BODY

Here we report the conclusions of an expert meeting convened by the World Health Organization and the Bill and Melinda Gates Foundation to discuss these findings, and present five key consensus messages as a basis for wider discussion and debate in the WASH and nutrition sectors. We judge these trials to have high internal validity, constituting good evidence that these specific interventions had no effect on childhood linear growth, and mixed effects on childhood diarrhea. These results suggest that, in settings such as these, more comprehensive or ambitious WASH interventions may be needed to achieve a major impact on child health.

CONCLUSION

These results are important because such basic interventions are often deployed in low-income rural settings with the expectation of improving child health, although this is rarely the sole justification. Our view is that these three new trials do not show that WASH in general cannot influence child linear growth, but they do demonstrate that these specific interventions had no influence in settings where stunting remains an important public health challenge. We support a call for transformative WASH, in so much as it encapsulates the guiding principle that - in any context - a comprehensive package of WASH interventions is needed that is tailored to address the local exposure landscape and enteric disease burden.

Health Risks for Sanitation Service Workers along a Container-Based Urine Collection System and Resource Recovery Value Chain

Container-based sanitation (CBS) within a comprehensive service system value chain offers a low-cost sanitation option with potential for revenue generation but may increase microbial health risks to sanitation service workers. This study assessed occupational exposure to rotavirus and Shigella spp. during CBS urine collection and subsequent struvite fertilizer production in eThekwini, South Africa. Primary data included high resolution sequences of hand-object contacts from annotated video and measurement of fecal contamination from urine and surfaces likely to be contacted. A stochastic model incorporated chronological surface contacts, pathogen concentrations in urine, and literature data on transfer efficiencies of pathogens to model pathogen concentrations on hands and risk of infection from hand-to-mouth contacts. The probability of infection was highest from exposure to rotavirus during urine collection (∼10-1) and struvite production (∼10-2), though risks from Shigella spp. during urine collection (∼10-3) and struvite production (∼10-4) were non-negligible. Notably, risk of infection was higher during urine collection than during struvite production due to contact with contaminated urine transport containers. In the scale-up of CBS, disinfection of urine transport containers is expected to reduce pathogen transmission. Exposure data from this study can be used to evaluate the effectiveness of measures to protect sanitation service workers.

Risk Factors Associated with Feeding Children under 2 Years in Rural Malawi-A Formative Study

Diarrhoeal disease remains one of the leading causes of morbidity and mortality in the under-five population, particularly in low income settings such as sub-Saharan Africa. Despite significant progress in sanitation and water access, faecal-oral infections persist in these populations. Therefore, a better understanding of these transmission pathways, and how potential risk factors can be reduced within low income contexts is needed. This study, conducted in Southern Malawi from June to October 2017, used a mixed methods approach to collect data from household surveys (n = 323), checklists (n = 31), structured observations (n = 80), and microbiological food samples (n = 20). Results showed that food prepared for immediate consumption (primarily porridge for children) posed a low health risk. Poor hygiene practices increased the risk of contamination from shared family meals. Faecal and nosocomial bacteria were associated with poor hand hygiene and unhygienic eating conditions. Leftover food storage and inadequate pre-consumption heating increased the risk of contamination. Improvements in food hygiene and hand hygiene practices at critical points could reduce the risk of diarrhoeal disease for children under 2 years but must consider the contextual structural barriers to improved practice like access to handwashing facilities, soap, food and water storage.

Child Defecation and Feces Disposal Practices and Determinants among Households after a Combined Household-Level Piped Water and Sanitation Intervention in Rural Odisha, India

Latrine access alone may be insufficient to encourage households to dispose of young children's feces safely in a latrine, and little is known about the determinants of improved child feces disposal. We used longitudinal data collected at up to three timepoints for children less than 5 years of age from households in Odisha, India, which received a combined household-level piped water supply and sanitation intervention, but did not specifically promote the safe disposal of child feces. Among the 85% of intervention households who reported access to improved sanitation, we characterized child defecation and feces disposal practices by age, across time, and season, and assessed determinants of improved disposal. Feces from children less than 3 years of age was commonly picked up by caregivers but disposed of unsafely with garbage into open areas (56.3% of households) or in a drain/ditch (6.2%). Although children 3 and 4 years were more likely to use a latrine than younger children, their feces was also more likely to be left in the open if they did not defecate in a latrine. For children less than 5 years of age, most (84.7%) children's feces that was safely disposed of in a latrine was because of the children defecating in the latrine directly. Significant predictors for disposing of child feces in an improved latrine were the primary female caregiver reporting using a latrine to defecate, the child's age, and water observed at place for handwashing. These findings suggest that child feces interventions should focus on encouraging children to begin using a toilet at a younger age and changing the common behavior of disposing of young child's feces into open areas.

The landscape of enteric pathogen exposure of young children in public domains of low-income, urban Kenya: The influence of exposure pathway and spatial range of play on multi-pathogen exposure risks

Young children are infected by a diverse variety of enteric pathogens in low-income, high-burden countries. Little is known about which conditions pose the greatest risk for enteric pathogen exposure and infection. Young children frequently play in residential public areas around their household, including areas contaminated by human and animal feces, suggesting these exposures are particularly hazardous. The objective of this study was to examine how the dose of six types of common enteric pathogens, and the probability of exposure to one or multiple enteric pathogens for young children playing at public play areas in Kisumu, Kenya is influenced by the type and frequency of child play behaviors that result in ingestion of soil or surface water. Additionally, we examine how pathogen doses and multi-pathogen exposure are modified by spatial variability in the number of public areas children are exposed to in their neighborhood. A Bayesian framework was employed to obtain the posterior distribution of pathogen doses for a certain number of contacts. First, a multivariate mixed effects tobit model was used to obtain the posterior distribution of pathogen concentrations, and their interdependencies, in soil and surface water, based upon empirical data of enteric pathogen contamination in three neighborhoods of Kisumu. Then, exposure doses were estimated using behavioral contact parameters from previous studies and contrasted under different exposure conditions. Pathogen presence and concentration in soil varied widely across local (< 25 meter radius area) and neighborhood-level scales, but pathogens were correlated among distinct surface water samples collected near to each other. Multi-pathogen exposure of children at public play areas was common. Pathogen doses and the probability of multi-pathogen ingestion increased with: higher frequency of environmental contact, especially for surface water; larger volume of soil or water ingested; and with play at multiple sites in the neighborhood versus single site play. Child contact with surface water and soil at public play areas in their neighborhood is an important cause of exposure to enteric pathogens in Kisumu, and behavioral, environmental, and spatial conditions are determinants of exposure.

Risk Factors for Detection, Survival, and Growth of Antibiotic-Resistant and Pathogenic Escherichia coli in Household Soils in Rural Bangladesh

Soils in household environments in low- and middle-income countries may play an important role in the persistence, proliferation, and transmission of Escherichia coli Our goal was to investigate the risk factors for detection, survival, and growth of E. coli in soils collected from household plots. E. coli was enumerated in soil and fecal samples from humans, chickens, and cattle from 52 households in rural Bangladesh. Associations between E. coli concentrations in soil, household-level risk factors, and soil physicochemical characteristics were investigated. Susceptibility to 16 antibiotics and the presence of intestinal pathotypes were evaluated for 175 E. coli isolates. The growth and survival of E. coli in microcosms using soil collected from the households were also assessed. E. coli was isolated from 44.2% of the soil samples, with an average of 1.95 log10 CFU/g dry soil. Soil moisture and clay content were associated with E. coli concentrations in soil, whereas no household-level risk factor was significantly correlated. Antibiotic resistance and pathogenicity were common among E. coli isolates, with 42.3% resistant to at least one antibiotic, 12.6% multidrug resistant (≥3 classes), and 10% potentially pathogenic. Soil microcosms demonstrate growth and/or survival of E. coli, including an enteropathogenic extended-spectrum beta-lactamase (ESBL)-producing isolate, in some, but not all, of the household soils tested. In rural Bangladesh, defined soil physicochemical characteristics appear more influential for E. coli detection in soils than household-level risk factors. Soils may act as reservoirs in the transmission of antibiotic-resistant and potentially pathogenic E. coli and therefore may impact the effectiveness of water, sanitation, and hygiene interventions.IMPORTANCE Soil may represent a direct source or act as an intermediary for the transmission of antibiotic-resistant and pathogenic Escherichia coli strains, particularly in low-income and rural settings. Thus, determining risk factors associated with detection, growth, and long-term survival of E. coli in soil environments is important for public health. Here, we demonstrate that household soils in rural Bangladesh are reservoirs for antibiotic-resistant and potentially pathogenic E. coli strains and can support E. coli growth and survival, and defined soil physicochemical characteristics are drivers of E. coli survival in this environment. In contrast, we found no evidence that household-level factors, including water, sanitation, and hygiene indicators, were associated with E. coli contamination of household soils.

Effects of Single and Combined Water, Sanitation and Handwashing Interventions on Fecal Contamination in the Domestic Environment: A Cluster-Randomized Controlled Trial in Rural Bangladesh

Water, sanitation, and hygiene interventions have varying effectiveness in reducing fecal contamination in the domestic environment; delivering them in combination could yield synergies. We conducted environmental assessments within a randomized controlled trial in Bangladesh that implemented single and combined water treatment, sanitation, handwashing (WSH) and nutrition interventions (WASH Benefits, NCT01590095). After one and two years of intervention, we quantified fecal indicator bacteria in samples of drinking water (from source or storage), child hands, children's food and sentinel objects. In households receiving single water treatment interventions, Escherichia coli prevalence in stored drinking water was reduced by 50% and concentration by 1-log. E. coli prevalence in food was reduced by 30% and concentration by 0.5-log in households receiving single water treatment and handwashing interventions. Combined WSH did not reduce fecal contamination more effectively than its components. Interventions did not reduce E. coli in groundwater, on child hands and on objects. These findings suggest that WSH improvements reduced contamination along the direct transmission pathways of stored water and food but not along indirect upstream pathways. Our findings support implementing water treatment and handwashing to reduce fecal exposure through water and food but provide no evidence that combining interventions further reduces exposure.

High time-resolution simulation of E. coli on hands reveals large variation in microbial exposures amongst Vietnamese farmers using human excreta for agriculture

Infectious disease transmission is frequently mediated by the environment, where people's movements through and interactions with the environment dictate risks of infection and/or illness. Capturing these interactions, and quantifying their importance, offers important insights into effective interventions. In this study, we capture high time-resolution activity data for twenty-five Vietnamese farmers during collection and land application of human excreta for agriculture. Although human excreta use improves productivity, the use increases risks of enteric infections for both farmers and end users. In our study, the activity data are integrated with environmental microbial sampling data into a stochastic-mechanistic simulation of E. coli contamination on hands and E. coli ingested. Results from the study include frequent and variable contact rates for farmers' hands (from 34 to 1344 objects contacted per hour per hand), including highly variable hand-to-mouth contact rates (from 0 to 9 contacts per hour per hand). The frequency of hand-to-mouth contacts was substantially lower than the widely-used frequency previously reported for U.S. Office Workers. Environmental microbial contamination data highlighted ubiquitous E. coli contamination in the environment, including excreta, hands, toilet pit, handheld tools, soils, surfaces, and water. Results from the simulation suggest dynamic changes in E. coli contamination on hands, and wide variation in hand contamination and E. coli ingested amongst the farmers studied. Sensitivity analysis suggests that E. coli contamination on hands and ingested doses are most influenced by contamination of handheld tools, excreta, and the toilet pit as well as by frequency of hand-to-mouth contacts. The study findings are especially relevant given the context: no farmers reported adequate storage time of human excreta, and personal protective mask availability did not prevent hand-to-mouth contacts. Integrating high time-resolution activity data into exposure assessments highlights variation in exposures amongst farmers, and offers greater insight into effective interventions and their potential impacts.

Where Children Play: Young Child Exposure to Environmental Hazards during Play in Public Areas in a Transitioning Internally Displaced Persons Community in Haiti

Globally, gastrointestinal (GI) infections by enteric pathogens are the second-leading cause of morbidity and mortality in children under five years of age (≤5 years). While GI pathogen exposure in households has been rigorously examined, there is little data about young children's exposure in public domains. Moreover, public areas in low-income settings are often used for other waste disposal practices in addition to human feces, such as trash dumping in areas near households. If young children play in public domains, they might be exposed to interrelated and highly concentrated microbial, chemical, and physical hazards. This study performed structured observations at 36 public areas in an internally displaced persons community that has transitioned into a formal settlement in Haiti. We documented how often young children played in public areas and quantified behaviors that might lead to illness and injury. Children ≤5 years played at all public sites, which included infants who played at 47% of sites. Children touched and mouthed plastic, metal and glass trash, food and other objects from the ground, ate soil (geophagia) and drank surface water. They also touched latrines, animals, animal feces and open drainage canals. Hand-to-mouth contact was one of the most common behaviors observed and the rate of contact significantly differed among developmental stages (infants: 18/h, toddlers: 11/h and young children: 9/h), providing evidence that children could ingest trace amounts of animal/human feces on hands that may contain GI pathogens. These findings demonstrate that water, sanitation and hygiene interventions could be more effective if they consider exposure risks to feces in public domains. Furthermore, this research highlights the need for waste-related interventions to address the broader set of civil conditions that create unsafe, toxic and contaminated public environments where young children play.

Fecal Indicator Bacteria along Multiple Environmental Transmission Pathways (Water, Hands, Food, Soil, Flies) and Subsequent Child Diarrhea in Rural Bangladesh

Enteric pathogens can be transmitted through multiple environmental pathways, yet little is known about the relative contribution of each pathway to diarrhea risk among children. We aimed to identify fecal transmission pathways in the household environment associated with prospectively measured child diarrhea in rural Bangladesh. We measured the presence and levels of Escherichia coli in tube wells, stored drinking water, pond water, child hand rinses, courtyard soil, flies, and food in 1843 households. Gastrointestinal symptoms among children ages 0-60 months were recorded concurrently at the time of environmental sample collection and again a median of 6 days later. Incident diarrhea (3 or more loose stools in a 24-h period) was positively associated with the concentration of E. coli on child hands measured on the first visit (incidence rate ratio [IRR] = 1.23, 95% CI 1.06, 1.43 for a log₁₀ increase), while other pathways were not associated. In cross-sectional analysis, there were no associations between concurrently measured environmental contamination and diarrhea. Our findings suggest higher levels of E. coli on child hands are strongly associated with subsequent diarrheal illness rates among children in rural Bangladesh.

Child soil ingestion in rural Ghana - frequency, caregiver perceptions, relationship with household floor material and associations with child diarrhoea

OBJECTIVES

The objectives of this work were to evaluate (i) the prevalence and frequency of caregiver-reported soil ingestion by children, (ii) whether household flooring material in the bedroom (earth vs. concrete) affected caregiver-reported soil ingestion, (iii) whether caregiver-reported soil ingestion was associated with caregiver-reported diarrhoea and (iv) caregivers' perceptions of their children ingesting soil.

METHODS

We conducted 309 household surveys in northern Ghana, including 529 children under five (249 children aged 6-36 months), and measured faecal contamination in soil from 31 households.

RESULTS

Among all children, 15% were reported to have directly ingested soil in the past week, including 28% of children aged 6-36 months. Among children reported to have ingested soil, the median frequency was 14 times in the past week, and the median amount of soil ingested each time was half a handful. There was no association between household floor material and whether the caregiver observed a child directly ingesting soil. After adjusting for household floor material and other potential confounding variables, caregiver-reported soil ingestion was associated with caregiver-reported diarrhoea for children under five [adjusted odds ratio (adj. OR) = 3.13, 95% confidence interval (CI) 2.76-3.55] and children aged 6-36 months (adj. OR = 2.61, 95% CI 2.01-3.39). Approximately 83% of caregivers whose children ingested soil reported they thought it was unsafe and were more likely to report stopping their child from ingesting soil, but these responses did not affect the quantity of soil ingested.

CONCLUSIONS

Our results suggest direct soil ingestion is associated with diarrhoea independent of household floor material, and separate interventions may be necessary to prevent exploratory soil ingestion.

Unsafe disposal of feces of children <3 years among households with latrine access in rural Bangladesh: Association with household characteristics, fly presence and child diarrhea

BACKGROUND

Young children frequently defecate in the living environment in low-income countries. Unsafe child feces disposal has been associated with risk of diarrhea. Additionally, reported practices can underestimate socially undesirable unhygienic behaviors. This analysis aimed to assess (1) the sensitivity of reported child feces disposal practices as an indicator for observed presence of human feces in the domestic environment, (2) household characteristics associated with reported unsafe feces disposal and (3) whether unsafe feces disposal is associated with fly presence and diarrhea among children <3 years.

METHODS

We recorded caregiver-reported feces disposal practices for children <3 years; unsafe disposal was defined as feces put/rinsed into a drain, ditch, bush or garbage heap or left on the ground and safe disposal as feces put/rinsed into latrine or specific pit or buried. We conducted spot checks for human feces, counted flies in the compound and recorded caregiver-reported child diarrhea prevalence among 803 rural Bangladeshi households. We assessed associations using generalized estimating equations (GEE) and generalized linear models (GLM) with robust standard errors.

RESULTS

Unsafe disposal of child feces was reported by 80% of households. Reported disposal practices had high sensitivity (91%) but low positive predictive value (15%) as an indicator of observed feces in the compound. Unsafe disposal was more common among households that reported daily adult open defecation (PR: 1.13, 1.02-1.24) and had children defecating in a nappy or on the ground versus in a potty (PR: 2.92, 1.98-4.32), and less common in households where adults reported always defecating in latrines (PR: 0.91, 0.84-0.98). The presence of observed human feces was similarly associated with these household characteristics. Reported unsafe feces disposal or observed human feces were not associated with fly detection or child diarrhea.

CONCLUSION

Despite access to on-site sanitation, unsafe child feces disposal was reported by the majority of households. However, this practices was not associated with diarrhea; suggesting that child feces may not be the most important fecal exposure. Before resources are invested to improve child feces management practices, studies should explore whether these contribute meaningfully to risk of enteric disease.

Oral Contact Events and Caregiver Hand Hygiene: Implications for Fecal-Oral Exposure to Enteric Pathogens among Infants 3-9 Months Living in Informal, Peri-Urban Communities in Kisumu, Kenya

Childhood diarrhea is one of the leading causes of morbidity and mortality in children under five in low and middle-income countries, second only to respiratory illness. The mouthing behavior that is common in children exposes them to fecal-orally transmitted pathogens that can result in diarrhea; however, there is a need for further evidence on specific exposure routes. This study describes the frequency and diversity of two important routes of enteric pathogen exposure among infants 3-9 months of age: infant oral contact behavior and caregiver handwashing behavior. Data were collected through structured observations of 25 index infants for the oral contact data and 25 households for the caregiver handwashing data in a peri-urban setting in Kisumu (Obunga), Kenya. Breast was the most common type of oral contact event with an average of 3.00 per observation period and 0.5 events per hour. This was followed by a range of physical objects with an average of 2.49 per observation and 0.4 events per hour. The "infant's own hands" was the third most common oral contact, with an average of 2.16 events per hour, and 0.4 oral contact events per hour. Food and liquids were the 4th and 5th most common oral contact events with an average of 1.64 food contacts and 0.52 liquid oral contact events per observation period. Feeding events, including breastfeeding, were the most commonly observed key juncture-71% of total junctures observed were caregivers feeding children. This was followed by child cleaning (23%), caregiver toilet uses at (4%), and lastly food preparation at 2%. HWWS was observed only once before a feeding event (1%), twice after cleaning a child (9%), and twice after caregiver toilet use (40%). The combined implication of data from observing oral contact behavior in children and hand hygiene of caregivers suggests that caregiver hand hygiene prior to feeding events and after cleaning a child are priority interventions.

Virus Transfer at the Skin-Liquid Interface

Understanding virus transfer between liquid and skin is necessary to estimate transmission during water-related activities. Here, we modeled virus transfer from liquid-to-skin and skin-to-liquid. We performed human subject studies using three bacteriophages as pathogenic virus surrogates: nonenveloped MS2 and Qβ and enveloped Φ6. Our study shows that transfer from liquid-to-skin is describable by a single model based on (1) virus concentration and (2) volume of liquid remaining on skin. Contact times (0.1-30 min), and virus species had little-to-no influence on virus transfer. Likewise, liquid conditions (pH 6-9, ionic strength 10-550 mM) had no influence on transfer as shown for MS2. The model accounts for both, virus adsorbed onto the skin, and virus in the liquid retained on skin. In comparison, virus transfer from skin-to-liquid was influenced by the wetness of the skin and by liquid type (water, saliva). 90 ± 19% of the virus inoculated on the skin are transferred to the water when the skin remains wet compared to 30 ± 17% when the skin is dry. The transfer from skin-to-liquid was 41% higher when the recipient liquid was water as compared with saliva. This study quantifies virus transfer between liquid and skin and guides risk assessments of water-related activities.

Animal Feces Contribute to Domestic Fecal Contamination: Evidence from E. coli Measured in Water, Hands, Food, Flies, and Soil in Bangladesh

Fecal-oral pathogens are transmitted through complex, environmentally mediated pathways. Sanitation interventions that isolate human feces from the environment may reduce transmission but have shown limited impact on environmental contamination. We conducted a study in rural Bangladesh to (1) quantify domestic fecal contamination in settings with high on-site sanitation coverage; (2) determine how domestic animals affect fecal contamination; and (3) assess how each environmental pathway affects others. We collected water, hand rinse, food, soil, and fly samples from 608 households. We analyzed samples with IDEXX Quantitray for the most probable number (MPN) of E. coli. We detected E. coli in source water (25%), stored water (77%), child hands (43%), food (58%), flies (50%), ponds (97%), and soil (95%). Soil had >120 000 mean MPN E. coli per gram. In compounds with vs without animals, E. coli was higher by 0.54 log10 in soil, 0.40 log10 in stored water and 0.61 log10 in food (p < 0.05). E. coli in stored water and food increased with increasing E. coli in soil, ponds, source water and hands. We provide empirical evidence of fecal transmission in the domestic environment despite on-site sanitation. Animal feces contribute to fecal contamination, and fecal indicator bacteria do not strictly indicate human fecal contamination when animals are present.

Mouthing of Soil Contaminated Objects is Associated with Environmental Enteropathy in Young Children

OBJECTIVE

To characterise childhood mouthing behaviours and to investigate the association between object-to-mouth and food-to-mouth contacts, diarrhoea prevalence and environmental enteropathy.

METHODS

A prospective cohort study was conducted of 216 children ≤30 months of age in rural Bangladesh. Mouthing contacts with soil and food and objects with visible soil were assessed by 5-h structured observation. Stool was analysed for four faecal markers of intestinal inflammation: alpha-1-antitrypsin, myeloperoxidase, neopterin and calprotectin.

RESULTS

Overall 82% of children were observed mouthing soil, objects with visible soil, or food with visible soil during the structured observation period. Sixty two percent of children were observed mouthing objects with visible soil, 63% were observed mouthing food with visible soil, and 18% were observed mouthing soil only. Children observed mouthing objects with visible soil had significantly elevated faecal calprotectin concentrations (206.81 μg/g, 95% confidence interval [CI]: 6.27, 407.36). There was also a marginally significant association between Escherichia coli counts in soil from a child's play space and the prevalence rate of diarrhoea (diarrhoea prevalence ratio: 2.03, 95% CI 0.97, 4.25).

CONCLUSION

These findings provide further evidence to support the hypothesis that childhood mouthing behaviour in environments with faecal contamination can lead to environmental enteropathy in susceptible paediatric populations. Furthermore, these findings suggest that young children mouthing objects with soil, which occurred more frequently than soil directly (60% vs. 18%), was an important exposure route to faecal pathogens and a risk factor for environmental enteropathy.

A Review of the Field on Children's Exposure to Environmental Contaminants: A Risk Assessment Approach

Background: Children must be recognized as a sensitive population based on having biological systems and organs in various stages of development. The processes of absorption, distribution, metabolism and elimination of environmental contaminants within a child's body are considered less advanced than those of adults, making them more susceptible to disease outcomes following even small doses. Children's unique activities of crawling and practicing increased hand-to-mouth ingestion also make them vulnerable to greater exposures by certain contaminants within specific environments. Approach: There is a need to review the field of children's environmental exposures in order to understand trends and identify gaps in research, which may lead to better protection of this vulnerable and sensitive population. Therefore, explored here are previously published contemporary works in the broad area of children's environmental exposures and potential impact on health from around the world. A discussion of children's exposure to environmental contaminants is best organized under the last four steps of a risk assessment approach: hazard identification, dose-response assessment, exposure assessment (including children's activity patterns) and risk characterization. We first consider the many exposure hazards that exist in the indoor and outdoor environments, and emerging contaminants of concern that may help guide the risk assessment process in identifying focus areas for children. A section on special diseases of concern is also included. Conclusions: The field of children's exposures to environmental contaminants is broad. Although there are some well-studied areas offering much insight into children exposures, research is still needed to further our understanding of exposures to newer compounds, growing disease trends and the role of gene-environment interactions that modify adverse health outcomes. It is clear that behaviors of adults and children play a role in reducing or increasing a child's exposure, where strategies to better communicate and implement risk modifying behaviors are needed, and can be more effective than implementing   changes in the physical environment.

The management of the faeces passed by under five children: an exploratory, cross-sectional research in an urban community in Southwest Nigeria

Background

Safe management of faeces (SMoF) and environmental contamination by faecal pathogens have been extensively researched although the SMoF in under-five children has been perennially neglected perhaps due to the misconception that it is harmless. This research, therefore, studied the situation, to determine the magnitude and dimensions of the problem aimed at making policy level stakeholders aware of child faeces management systems and so, inform evidence-based implementation of child and health-related programmes in Nigeria.

Methods

The study utilized an exploratory cross-sectional design and a multi-stage sampling technique to identify 300 respondents from 12 randomly selected streets from 4 wards in Ife central local government area. The study collected data with a pretested questionnaire which included direct observations of child defecation practices and existing toilet facilities. Cleaned data were analyzed by IBM-SPSS version 20 with child faeces management outcomes as the dependent variable.

Results

The mean age of respondents’ and monthly income (mode) were 30.8 ± 7.5 years and ₦10,000.00 ($28.60). Most respondents were mothers to the under five children (84.7%), had a secondary education (72.0%) and were semi-skilled (57.0%). The caregivers had access to improved water sources (93.7%), improved toilets (64.3%), with 64% and 53.7% having above average scores in knowledge and attitudes, respectively. In the study, 19.7% and 69.0% of caregivers practiced safe disposal of faeces passed by the under five child during the day and at night respectively, though most caregivers (94.3%) omitted steps in the safe management of child faeces chain. The under five diarrhoea prevalence rate was 13.7% and unsanitary passage of child faeces is associated with four folds likelihood of having diarrhoea (p = 0.001). The caregivers whose under five children practiced safe sanitation were rich (p = 0.009) and knowledge was significantly associated with ownership of household toilet (P = 0.037), night faeces management chain practice (P < 0.001) and disposal of anal cleaning materials (P = 0.002). Handwashing was significantly associated with household toilet (P < 0.001), wealth (P < 0.001), under five child defecation preferences during the day (P < 0.001) and at night (P = 0.008).

Conclusion

The high knowledge and positive attitudes exhibited by the caregivers were at variance with practice. Where under five children defecate during the day were influenced by the disposal of their anal cleaning materials, distance to the toilet and caregivers’ education. The findings highlight the dangers of unsanitary disposal of child faeces and the need to strengthen the related policies that can increase caregivers awareness and practice at all levels and in all livelihood domains.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4078-1) contains supplementary material, which is available to authorized users.