Urban sanitation coverage and environmental fecal contamination: Links between the household and public environments of Accra, Ghana

Clustering of Gastrointestinal Microorganisms in Human Stool Samples from Ghana

The study was conducted to identify cluster patterns of enteric microorganisms with potential etiological relevance for infectious gastroenteritis in stool samples of individuals from Ghana, which is a known high-endemicity setting for infectious gastroenteritis. These patterns were compared to previous observations with specimens from Colombian indigenous people in order to assess potentially stable clustering for temporally and spatially distinct populations from high-endemicity regions. By doing so, the study aimed to identify stable clusters as markers of microbial interaction with potential importance for etiological relevance assignment in cases of multiple enteric pathogen detections. Stool samples from 1569 Ghanaian individuals (875 from HIV patients, 30 from HIV-negative control adult patients, and 644 from children < 2 years of age) were assessed for enteric microorganisms by applying real-time PCR. As a result, nucleic acids of bacterial microorganisms were most frequently detected, followed by protozoa, microsporidia, and helminths. Interestingly, the cluster assessment confirmed interaction patterns known from the previous analysis with Colombian indigenous people, demonstrating a high likelihood of Blastocystis hominis for clustering with other microorganisms and a prominent, potentially mediating role of Dientamoeba fragilis for microbial interactions within the clusters. In conclusion, the assessment confirmed conserved clustering of enteric microorganisms with potential etiological relevance for human infectious gastroenteritis over geographically distinct high-endemicity settings. Furthermore, the composition of abundant microorganisms is more important than regional factors for the determination of the interplay of enteric microorganisms in the human gut. Thereby, some microbial pathogens and commensals seem more susceptible to a changing microbial composition in the human gut than others.

Indicators to complement global monitoring of safely managed on-site sanitation to understand health risks

Halfway through the Sustainable Development Goal (SDG) period, there has been little research on the criteria for monitoring safely managed sanitation under SDG target 6.2. For reporting against SDGs, global indicators are necessarily limited and exclude many safety aspects from a public health perspective. Primary survey data from 31,784 households in seven countries in Asia and Africa were analysed, comparing estimates of safely managed on-site sanitation based on global indicators with five complementary indicators of safety: animal access to excreta, groundwater contamination, overdue emptying, entering containments to empty and inadequate protection during emptying. Application of additional criteria reduced the population with safely managed sanitation by 0.4-35% for specific indicators, with the largest impact due to the risk of groundwater contamination, animal access, and containments overdue for emptying. Combining these indicators across the service chain, excluding transport and treatment, found almost three-quarters of on-site systems currently assessed as safely managed with global indicators were considered unsafe based on complementary indicators. A more comprehensive assessment of safety of on-site sanitation can be achieved through these indicators, which could be integrated into national monitoring systems and used to inform sanitation investments that address local health-related risks.

Mapping and predicting open defecation in Ethiopia: 2021 PMA-ET study

INTRODUCTION

There has been extensive research conducted on open defecation in Ethiopia, but a notable gap persists in comprehensively understanding the spatial variation and predictors at the household level. This study utilizes data from the 2021 Performance Monitoring for Action Ethiopia (PMA-ET) to address this gap by identifying hotspots and predictors of open defecation. Employing geographically weighted regression analysis, it goes beyond traditional models to account for spatial heterogeneity, offering a nuanced understanding of geographical variations in open defecation prevalence and its determinants. This research pinpoints hotspot areas and significant predictors, aiding policymakers and practitioners in tailoring interventions effectively. It not only fills the knowledge gap in Ethiopia but also informs global sanitation initiatives.

METHODS

The study comprised a total weighted sample of 24,747 household participants. ArcGIS version 10.7 and SaT Scan version 9.6 were used to handle mapping, hotspots, ordinary least squares, Bernoulli model analysis, and Spatial regression. Bernoulli-based model was used to analyze the purely spatial cluster detection of open defecation at the household level in Ethiopia. Ordinary Least Square (OLS) analysis and geographically weighted regression analysis were employed to assess the association between an open defecation and explanatory variables.

RESULTS

The spatial distribution of open defecation at the household level exhibited clustering (global Moran's I index value of 4.540385, coupled with a p-value of less than 0.001), with significant hotspots identified in Amhara, Afar, Harari, and parts of Dire Dawa. Spatial analysis using Kuldorff's Scan identified six clusters, with four showing statistical significance (P-value < 0.05) in Amhara, Afar, Harari, Tigray, and southwest Ethiopia. In the geographically weighted regression model, being male [coefficient = 0.87, P-value < 0.05] and having no media exposure (not watching TV or listening to the radio) [coefficient = 0.47, P-value < 0.05] emerged as statistically significant predictors of household-level open defecation in Ethiopia.

CONCLUSION

The study revealed that open defecation at the household level in Ethiopia varies across the regions, with significant hotspots identified in Amhara, Afar, Harari, and parts of Dire Dawa. Geographically weighted regression analysis highlights male participants lacking media exposure as substantial predictors of open defecation. Targeted interventions in Ethiopia should improve media exposure among males in hotspot regions, tailored sanitation programs, and region-specific awareness campaigns. Collaboration with local communities is crucial.

Assessing the Influence of Hand-Dug Well Features and Management on Water Quality

Underground water quality can be affected by natural or human-made influences. This study investigates how the management and characteristics of hand-dug wells impact water quality in 3 suburbs of Kumasi, Ghana, using a combination of qualitative and quantitative research methods. Descriptive analysis, including frequency and percentages, depicted the demographic profiles of respondents. Box plot diagrams illustrated the distribution of physicochemical parameters (Total Dissolved Solid [TDS], Electrical Conductivity [EC], Turbidity, Dissolved Oxygen [DO], and Temperature). Factor analysis evaluated dominant factors among these parameters. Cluster analysis (hierarchical clustering) utilized sampling points as variables to establish spatial variations in water physicochemical parameters. Cramer's V correlation test explored relationships between demographic variables and individual perceptions of water management. One-way ANOVA verified significant mean differences among the physicochemical parameters. Logistic regression models assessed the influence of selected well features (e.g., cover and apron) on TDS, pH, Temperature, Turbidity, and DO. The findings revealed that proximity to human settlements affects water quality, and increasing turbidity is associated with unmaintained covers, significantly impacting water quality (P < .05). Over 80% of wells were located within 10 to 30 m of pollution sources, with 65.63% situated in lower ground and 87.5% being unmaintained. Other significant contamination sources included plastic bucket/rope usage (87.50%), defective linings (75%), and apron fissures (59.37%). Presence of E. coli, Total coliform, and Faecal coliform rendered the wells unpotable. Factor analysis attributed 90.85% of time-based and spatial differences to organic particle decomposition factors. However, Cramer's V correlation analysis found establishing association between demographic factor associations with individual perceptions of hand-dug well management difficult. It is encouraged to promote hand-dug well construction and maintenance standards to ensure that wells are properly built and protected from contamination sources.

Experimental evaluation of fresh human feces biogas and compost potential: Evidence for circular economy from waste streams in Ethiopia

Biogas toilets are one of the most resource-efficient sanitation technologies. The technology has dual purposes of generating energy and stabilizing waste-producing biofertilizers. In Ethiopia, knowledge of human feces' energy potential is limited to optimize the development of biogas toilet facilities. Therefore, this study was aimed to evaluate the biogas and biofertilizer potential of human feces in Jimma City, Ethiopia, which may contribute to the development of sustainable sanitation technologies. The study was lab-based experimental design. In the lab-scale batch experiment, fresh human excreta samples were collected using a urine diversion raised toilet. Using ultimate and proximate laboratory analyses, the theoretical yield of biogas was predicted. Then a series of anaerobic digestion batch experiments were conducted to determine the practical energy yield. The bio-fertilizer potential of human feces was determined by analyzing the nutrient contents of human feces. The findings of this study showed that the bio-methane yield from the experimental results has a mean of 0.393 m3 kg-1, which is 14.16 MJ kg-1. The bio-methane meter cube per capita per head per year were 28.71 (28.03-29.27) from the experimental result and 45.26 for the theoretical yield of methane. In this study, the bio-fertilizer potential of human feces was evaluated using nutrient analysis, specifically the NPK (nitrogen, phosphorus, and potassium). Accordingly, human feces contain potassium (2.29 mg kg-1), phosphorus (1.12 mg kg-1), and nitrogen (3.71 mg kg-1). This finding suggests the bio-methane potential of human feces can be used for energy recovery and alternative sanitation options, providing a positive remedy for the sanitation crisis in urban settings.

Somewhere to go: assessing the impact of public restroom interventions on reports of open defecation in San Francisco, California from 2014 to 2020

BACKGROUND

Open defecation due to a lack of access to sanitation facilities remains a public health issue in the United States. People experiencing homelessness face barriers to accessing sanitation facilities, and are often forced to practice open defecation on streets and sidewalks. Exposed feces may contain harmful pathogens posing a significant threat to public health, especially among unhoused persons living near open defecation sites. The City of San Francisco's Department of Public Works implemented the Pit Stop Program to provide the unhoused and the general public with improved access to sanitation with the goal of reducing fecal contamination on streets and sidewalks. The objective of this study was to assess the impact of these public restroom interventions on reports of exposed feces in San Francisco, California.

METHODS

We evaluated the impact of various public restroom interventions implemented from January 1, 2014 to January 1, 2020 on reports of exposed feces, captured through a 311 municipal service. Publicly available 311 reports of exposed feces were spatially and temporally matched to 31 Pit Stop restroom interventions at 27 locations across 10 San Francisco neighborhoods. We conducted an interrupted time-series analysis to compare pre- versus post-intervention rates of feces reports near the restrooms.

RESULTS

Feces reports declined by 12.47 reports per week after the installation of 13 Pit Stop restrooms (p-value = 0.0002). In the same restrooms, the rate of reports per week declined from the six-month pre-intervention period to the post-intervention period (slope change = -0.024 [95% CI = -0.033, -0.014]). In a subset of restrooms, where new installations were made (Mission and Golden Gate Park), and in another subset of restrooms where restroom attendants were provided (Mission, Castro/Upper Market, and Financial District/South Beach), feces reports also declined.

CONCLUSIONS

Increased access to public toilets reduced feces reports in San Francisco, especially in neighborhoods with people experiencing homelessness. The addition of restroom attendants also appeared to have reduced feces reports in some neighborhoods with PEH. These interventions should be audited for implementation quality, observed utilization data, and user experience at the neighborhood level in order to tailor sanitation interventions to neighborhood-specific needs.

A systematic review of enteric pathogens and antibiotic resistance genes in outdoor urban aerosols

Aerosol transport of enteric microbiota including fecal pathogens and antimicrobial resistance genes (ARGs) has been documented in a range of settings but remains poorly understood outside indoor environments. We conducted a systematic review of the peer-reviewed literature to summarize evidence on specific enteric microbiota including enteric pathogens and ARGs that have been measured in aerosol samples in urban settings where the risks of outdoor exposure and antibiotic resistance (AR) spread may be highest. Following PRISMA guidelines, we conducted a key word search for articles published within the years 1990-2020 using relevant data sources. Two authors independently conducted the keyword searches of databases and conducted primary and secondary screenings before merging results. To be included, studies contained extractable data on enteric microbes and AR in outdoor aerosols regardless of source confirmation and reported on qualitative, quantitative, or viability data on enteric microbes or AR. Qualitative analyses and metric summaries revealed that enteric microbes and AR have been consistently reported in outdoor aerosols, generally via relative abundance measures, though gaps remain preventing full understanding of the role of the aeromicrobiological pathway in the fate and transport of enteric associated outdoor aerosols. We identified remaining gaps in the evidence base including a need for broad characterization of enteric pathogens in bioaerosols beyond bacterial genera, a need for greater sampling in locations of high enteric disease risk, and a need for quantitative estimation of microbial and nucleic acid densities that may be applied to fate and transport models and in quantitative microbial risk assessment.

Influence of community-level sanitation coverage and population density on environmental fecal contamination and child health in a longitudinal cohort in rural Bangladesh

BACKGROUND

Household-level sanitation interventions have had limited effects on child health or environmental contamination, potentially due to low community coverage. Higher community-level coverage with safely managed sanitation can reduce opportunities for disease transmission.

METHODS

We estimated associations between community sanitation coverage, environmental fecal contamination, and child health among 360 compounds in the control arm of the WASH Benefits trial in rural Bangladesh (NCT01590095). In each compound, we enumerated E. coli in environmental samples and recorded the 7-day prevalence of caregiver-reported diarrheal disease and acute respiratory infections (ARI) in children under five. We observed indicators of latrine access and quality among all neighboring compounds within 100 m of study compounds. We defined community coverage as the proportion of neighboring compounds with (1) at least one latrine, and (2) exclusively hygienic latrines (improved facility observed to safely contain feces), within both 50 m and 100 m of study compounds. We assessed effect modification by population density and season.

RESULTS

Adjusted for confounders, study compounds surrounded by 100% coverage of at least one latrine per compound within 50 m had slightly lower log10E. coli counts in stored water (Δlog = -0.13, 95% CI -0.26, -0.01), child hand rinses (Δlog = -0.13, 95% CI -0.24, -0.02), and caregiver hand rinses (Δlog = -0.16, 95% CI -0.29, -0.03) and marginally lower prevalence of diarrheal disease (prevalence ratio [PR] = 0.82, 95% CI 0.64, 1.04) and ARI (PR = 0.84, 95% CI 0.69, 1.03) compared to compounds surrounded by <100% coverage. Effects were similar but less pronounced at 100 m. At higher population densities, community latrine coverage was associated with larger reductions in E. coli on child and caregiver hands and prevalence of diarrheal disease. Coverage with exclusively hygienic latrines was not associated with any outcome.

CONCLUSION

Higher community sanitation coverage was associated with reduced fecal contamination and improved child health, with stronger effects at highly local scales (50m) and at high population densities. Our findings indicate that the relationship between community sanitation coverage, environmental contamination, and child health varies by definition of coverage, distance, and population density. This work highlights significant uncertainty around how to best measure sanitation coverage and the expected health effects of increasing sanitation coverage using a specific metric. Better understanding of community-level sanitation access is needed to inform policy for implementing sanitation systems that effectively protect community health.

Out of sight, out of mind: Understanding the sanitation crisis in global South cities

Global monitoring efforts do not provide a clear picture of the challenge of managing human waste at the city scale. Where cities do not provide universal access to publicly managed sanitation systems, households and communities find their own solutions resulting in a patchwork of approaches to removing human waste from places where people live. In dense urban environments, the absence of a coordinated approach can create serious public health problems. In the absence of comparable city-level data, we analyze primary and secondary data from 15 cities and 15 informal settlements in sub-Saharan Africa, South Asia, and Latin America. Across these regions, our study finds that 62 percent of human waste is not safely managed. We also find that, while many cities have a proportion of households connected to sewers, none of the 15 cities safely manage human waste at scale. In the absence of sewers, on-site fecal sludge management systems place enormous responsibility on households and private providers, and unaffordable sanitation options result in risky sanitation practices.

Sachet water in Ghana: A spatiotemporal analysis of the recent upward trend in consumption and its relationship with changing household characteristics, 2010-2017

The consumption of packaged water in Ghana has grown significantly in recent years. By 2017, "sachet water"-machine-sealed 500ml plastic bags of drinking water-was consumed by 33% of Ghanaian households. Reliance on sachet water has previously been associated with the urban poor, yet recent evidence suggests a customer base which crosses socioeconomic lines. Here, we conduct a repeated cross-sectional analysis of three nationally representative datasets to examine the changing demography of sachet water consumers between 2010 and 2017. Our results show that over the course of the study period sachet water has become a ubiquitous source of drinking water in Ghana, with relatively wealthy households notably increasing their consumption. In 2017, the majority of sachet water drinking households had access to another improved water source. The current rate and form of urbanisation, inadequate water governance, and an emphasis on cost recovery pose significant challenges for the expansion of the piped water supply network, leading us to conclude that sachet water will likely continue to be a prominent source of drinking water in Ghana for the foreseeable future. The main challenge for policymakers is to ensure that the growing sachet water market enhances rather than undermines Ghana's efforts towards achieving universal and equitable access to clean drinking water and sanitation.

Modelling rotavirus concentrations in rivers: Assessing Uganda's present and future microbial water quality

Faecal pathogens can be introduced into surface water through open defecation, illegal disposal and inadequate treatment of faecal sludge and wastewater. Despite sanitation improvements, poor countries are progressing slowly towards the United Nation's Sustainable Development Goal 6 by 2030. Sanitation-associated pathogenic contamination of surface waters impacted by future population growth, urbanization and climate change receive limited attention. Therefore, a model simulating human rotavirus river inputs and concentrations was developed combining population density, sanitation coverage, rotavirus incidence, wastewater treatment and environmental survival data, and applied to Uganda. Complementary surface runoff and river discharge data were used to produce spatially explicit rotavirus outputs for the year 2015 and for two scenarios in 2050. Urban open defecation contributed 87%, sewers 9% and illegal faecal sludge disposal 3% to the annual 15.6 log₁₀ rotavirus river inputs in 2015. Monthly concentrations fell between -3.7 (Q5) and 2.6 (Q95) log₁₀ particles per litre, with 1.0 and 2.0 median and mean log₁₀ particles per litre, respectively. Spatially explicit outputs on 0.0833 × 0.0833° grids revealed hotspots as densely populated urban areas. Future population growth, urbanization and poor sanitation were stronger drivers of rotavirus concentrations in rivers than climate change. The model and scenario analysis can be applied to other locations.

A method for correcting underestimation of enteric pathogen genome quantities in environmental samples

Exposure to enteric pathogens in the environment poses a serious risk for infection and disease. The accurate detection and quantification of enteric pathogens in environmental samples is critical for understanding pathogen transport and fate and developing risk assessment models. In this study, we successfully applied TaqMan real-time PCR assays to quantitatively detect five human-specific pathogens (Shigella/EIEC, Salmonella Typhi, Vibrio cholera, Norovirus, and Giardia) in samples from open drains, canals, floodwater, septic tanks, and anaerobic baffled reactors (ABR) collected in Mirpur, Dhaka, Bangladesh from April to October 2019. Overall, the grab and sediment samples showed low inhibition but the ultrafiltration samples collected from open drain had significantly higher (P = 0.0049) degree of PCR inhibition (median Ct = 31.06) compared to the extraction controls (Ct = 28.54). We developed a two-step method to adjust underestimation of pathogen quantities due to PCR inhibition and non-optimum PCR efficiency. Compared to other sample types, ultrafiltration samples demonstrated a wide range of concentration increase (1.0%-182.5%) by pathogens after adjusting for PCR inhibition and non-optimum efficiencies. These quantitative qPCR assays are successful in quantifying multiple enteric pathogens in environmental samples, and the adjustment method would be useful for correcting underestimates of pathogen quantities due to partial PCR inhibition and non-optimum efficiency.

Safely Managed On-Site Sanitation: A National Assessment of Sanitation Services and Potential Fecal Exposure in Indonesia

Sustainable Development Goal target 6.2 calls for universal access to adequate and equitable sanitation, setting a more ambitious standard for 'safely managed sanitation services'. On-site sanitation systems (e.g., septic tanks) are widely used in low- and middle-income countries (LMICs). However, the lack of indicators for assessing fecal exposure risks presents a barrier to monitoring safely managed services. Furthermore, geographic diversity and frequency of disasters require a more nuanced approach to risk-informed decision-making. Taking Indonesia as an example, the purpose of this paper is to provide insights into current status and practices for on-site sanitation services in the contexts of LMICs. Using a dataset from a national socio-economic survey (n = 295,155) coupled with village census (n = 83,931), we assessed (1) household sanitation practices across Indonesia stratified by city-level population density and meteorological factors, (2) factors associated with septic tank emptying practice, and (3) inequalities in potential fecal exposure as measured by population density and WASH access by wealth quintile. We found a high reliance on on-site sanitation facilities (80.0%), almost half of which are assumed to be 'uncontained' septic tanks and one in ten facilities discharging untreated waste directly into the environment. The most densely populated areas had the highest rates of septic tank emptying, though emptying rates were just 17.0%, while in the lowest population density group, emptying was rarely reported. Multivariate regression analysis demonstrated an association between flooding and drought occurrence and septic tank emptying practice. Higher groundwater usage for drinking among poorer households suggests unsafe sanitation may disproportionally affect the poor. Our study underscores the urgent need to strengthen the monitoring of on-site sanitation in LMICs by developing contextualized standards. Furthermore, the inequalities in potential fecal exposure require greater attention and tailored support mechanisms to ensure the poorest gain access to safely managed sanitation services.

Impact of an Urban Sanitation Intervention on Enteric Pathogen Detection in Soils

Environmental fecal contamination is common in many low-income cities, contributing to a high burden of enteric infections and associated negative sequelae. To evaluate the impact of a shared onsite sanitation intervention in Maputo, Mozambique on enteric pathogens in the domestic environment, we collected 179 soil samples at shared latrine entrances from intervention (n = 49) and control (n = 51) compounds during baseline (preintervention) and after 24 months (postintervention) as part of the Maputo Sanitation Trial. We tested soils for the presence of nucleic acids associated with 18 enteric pathogens using a multiplex reverse transcription qPCR platform. We detected at least one pathogen-associated gene target in 91% (163/179) of soils and a median of 3 (IQR = 1, 5) pathogens. Using a difference-in-difference analysis and adjusting for compound population, visibly wet soil, sun exposure, wealth, temperature, animal presence, and visible feces, we estimate the intervention reduced the probability of detecting ≥1 pathogen gene by 15% (adjusted prevalence ratio, aPR = 0.85; 95% CI: 0.70, 1.0) and the total number of pathogens by 35% (aPR = 0.65; 0.44, 0.95) in soil 24 months following the intervention. These results suggest that the intervention reduced the presence of some fecal contamination in the domestic environment, but pathogen detection remained prevalent 24 months following the introduction of new latrines.

Occurrence of Human Enteric Viruses in Water Sources and Shellfish: A Focus on Africa

Enteric viruses are a diverse group of human pathogens which are primarily transmitted by the faecal-oral route and are a major cause of non-bacterial diarrhoeal disease in both developed and developing countries. Because they are shed in high numbers by infected individuals and can persist for a long time in the environment, they pose a serious threat to human health globally. Enteric viruses end up in the environment mainly through discharge or leakage of raw or inadequately treated sewage into water sources such as springs, rivers, dams, or marine estuaries. Human exposure then follows when contaminated water is used for drinking, cooking, or recreation and, importantly, when filter-feeding bivalve shellfish are consumed. The human health hazard posed by enteric viruses is particularly serious in Africa where rapid urbanisation in a relatively short period of time has led to the expansion of informal settlements with poor sanitation and failing or non-existent wastewater treatment infrastructure, and where rural communities with limited or no access to municipal water are dependent on nearby open water sources for their subsistence. The role of sewage-contaminated water and bivalve shellfish as vehicles for transmission of enteric viruses is well documented but, to our knowledge, has not been comprehensively reviewed in the African context. Here we provide an overview of enteric viruses and then review the growing body of research where these viruses have been detected in association with sewage-contaminated water or food in several African countries. These studies highlight the need for more research into the prevalence, molecular epidemiology and circulation of these viruses in Africa, as well as for development and application of innovative wastewater treatment approaches to reduce environmental pollution and its impact on human health on the continent.

Visible and invisible risks: Exploring washing and hygiene practices with women living on low income in Kenya

Shifting environmental conditions and poor or insufficient hygiene facilitates the transmission of bacteria and viruses between and within species of animals; between humans; and between humans and animals. Taking a One Health perspective, we used interviews to explore with 20 women living on low income in Kenya: their gendered hygiene practices and daily contact with animals; how and why they access water and sanitation facilities for themselves, their families, and any livestock; and their understandings of (zoonotic) health risks and disease transmission within their local environments. The women described how they worked every day to keep bodies and homes clean by washing bodies, surfaces and clothes. Women's hygiene practices focussed on removing visible dirt partly because of concerns for health but also to support their families' social standing in their community. While they were less aware of any 'invisible' risks to health through contact with animals or other hazards present in their daily living environments, most exercised care to source and manage water for drinking. Contaminated water was recognised as a risk to health suggesting that in this case, women accepted that there were 'invisible risks' to health, even in clear water, and took steps to mitigate them.

Modelling faecal pathogen flows and health risks in urban Bangladesh: Implications for sanitation decision making

Faecal-oral infections are a major component of the disease burden in low-income contexts, with inadequate sanitation seen as a contributing factor. However, demonstrating health effects of sanitation interventions - particularly in urban areas - has proved challenging and there is limited empirical evidence to support sanitation decisions that maximise health gains. This study aimed to develop, apply and validate a systems modelling approach to inform sanitation infrastructure and service decision-making in urban environments by examining enteric pathogen inputs, transport and reduction by various sanitation systems, and estimating corresponding exposure and public health impacts. The health effects of eight sanitation options were assessed in a low-income area in Dhaka, Bangladesh, with a focus on five target pathogens (Shigella, Vibrio cholerae, Salmonella Typhi, norovirus GII and Giardia). Relative to the sanitation base case in the study site (24% septic tanks, 5% holding tanks and 71% toilets discharging directly to open drains), comprehensive coverage of septic tanks was estimated to reduce the disease burden in disability-adjusted life years (DALYs) by 48-72%, while complete coverage of communal scale anaerobic baffled reactors was estimated to reduce DALYs by 67-81%. Despite these improvements, a concerning health risk persists with these systems as a result of effluent discharge to open drains, particularly when the systems are poorly managed. Other sanitation options, including use of constructed wetlands and small bore sewerage, demonstrated further reductions in local health risk, though several still exported pathogens into neighbouring areas, simply transferring risk to downstream communities. The study revealed sensitivity to and a requirement for further evidence on log reduction values for different sanitation systems under varying performance conditions, pathogen flows under flooding conditions as well as pathogen shedding and human exposure in typical low-income urban settings. Notwithstanding variability and uncertainties in input parameters, systems modelling can be a feasible and customisable approach to consider the relative health impact of different sanitation options across various contexts, and stands as a valuable tool to guide urban sanitation decision-making.

Quantitative Microbial Risk Assessment of Pediatric Infections Attributable to Ingestion of Fecally Contaminated Domestic Soils in Low-Income Urban Maputo, Mozambique

Rigorous studies of water, sanitation, and hygiene interventions in low- and middle-income countries (LMICs) suggest that children are exposed to enteric pathogens via multiple interacting pathways, including soil ingestion. In 30 compounds (household clusters) in low-income urban Maputo, Mozambique, we cultured Escherichia coli and quantified gene targets from soils (E. coli: ybbW, Shigella/enteroinvasive E. coli (EIEC): ipaH, Giardia duodenalis: β-giardin) using droplet digital PCR at three compound locations (latrine entrance, solid waste area, dishwashing area). We found that 88% of samples were positive for culturable E. coli (mean = 3.2 log10 CFUs per gram of dry soil), 100% for molecular E. coli (mean = 5.9 log10 gene copies per gram of dry soil), 44% for ipaH (mean = 2.5 log10), and 41% for β-giardin (mean = 2.1 log10). Performing stochastic quantitative microbial risk assessment using soil ingestion parameters from an LMIC setting for children 12-23 months old, we estimated that the median annual infection risk by G. duodenalis was 7100-fold (71% annual infection risk) and by Shigella/EIEC was 4000-fold (40% annual infection risk) greater than the EPA's standard for drinking water. Compounds in Maputo, and similar settings, require contact and source control strategies to reduce the ingestion of contaminated soil and achieve acceptable levels of risk.

Are There Seasonal Variations in Faecal Contamination of Exposure Pathways? An Assessment in a Low-Income Settlement in Uganda

Sanitation infrastructure are not able to cope with the increasing population in low-income countries, which leaves populations exposed to faecal contamination from multiple pathways. This study evaluated public health risk (using SaniPath) in a low-income community during the dry season, to identify the dominant exposure pathways, and compare this data to existing data for the rainy season, questioning the assumption that risk of faecal contamination is higher in the rainy season. SaniPath was used to collect and assess exposure and environmental data, and to generate risk profiles for each pathway. In the dry season the highest exposure frequency was for bathing and street food, exposure frequency generally increased, and seasonal variation was found in five pathways. The highest hazards in the dry season were through contact with drains, soil, and street food. Seasonal variation was found in the contamination of open drains and street food, with higher levels of Escherichia coli (E. coli) in the dry season. Open drains were identified as the most dominant risk pathway in both seasons, but risk was higher in the dry season. This highlights the complex nature of seasonal variation of faecal risk, and questions the assumption that risk is higher in the rainy season.

Human fecal contamination of water, soil, and surfaces in households sharing poor-quality sanitation facilities in Maputo, Mozambique

Identifying the origin of fecal contamination can support more effective interventions to interrupt enteric pathogen transmission. Microbial source tracking (MST) assays may help to identify environmental routes of pathogen transmission although these assays have performed poorly in highly contaminated domestic settings, highlighting the importance of both diagnostic validation and understanding the context-specific ecological, physical, and sociodemographic factors driving the spread of fecal contamination. We assessed fecal contamination of compounds (clusters of 2-10 households that share sanitation facilities) in low-income neighborhoods of urban Maputo, Mozambique, using a set of MST assays that were validated with animal stool and latrine sludge from study compounds. We sampled five environmental compartments involved in fecal microbe transmission and exposure: compound water source, household stored water and food preparation surfaces, and soil from the entrance to the compound latrine and the entrances to each household. Each sample was analyzed by culture for the general fecal indicator Escherichia coli (cEC) and by real-time PCR for the E. coli molecular marker EC23S857, human-associated markers HF183/BacR287 and Mnif, and GFD, an avian-associated marker. We collected 366 samples from 94 households in 58 compounds. At least one microbial target (indicator organism or marker gene) was detected in 96% of samples (353/366), with both E. coli targets present in the majority of samples (78%). Human targets were frequently detected in soils (59%) and occasionally in stored water (17%) but seldom in source water or on food surfaces. The avian target GFD was rarely detected in any sample type but was most common in soils (4%). To identify risk factors of fecal contamination, we estimated associations with sociodemographic, meteorological, and physical sample characteristics for each microbial target and sample type combination using Bayesian censored regression for target concentration responses and Bayesian logistic regression for target detection status. Associations with risk factors were generally weak and often differed in direction between different targets and sample types, though relationships were somewhat more consistent for physical sample characteristics. Wet soils were associated with elevated concentrations of cEC and EC23S857 and odds of detecting HF183. Water storage container characteristics that expose the contents to potential contact with hands and other objects were weakly associated with human target detection. Our results describe a setting impacted by pervasive domestic fecal contamination, including from human sources, that was largely disconnected from the observed variation in socioeconomic and sanitary conditions. This pattern suggests that in such highly contaminated settings, transformational changes to the community environment may be required before meaningful impacts on fecal contamination can be realized.

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.

Variation in E. coli concentrations in open drains across neighborhoods in Accra, Ghana: The influence of onsite sanitation coverage and interconnectedness of urban environments

Alongside efforts to improve safe management of feces along the entire sanitation chain, including after the toilet, global sanitation efforts are focusing on universal access 'basic' services: onsite facilities that safely contain excreta away from human contact. Although fecal sludge management is improving in urban areas, open drains remain a common fate for feces in these often densely-populated neighborhoods in low-income countries. To-date, it is unclear to what extent complete coverage of onsite sanitation reduces fecal contamination in the urban environment and how fecal contamination varies within urban drains across neighborhoods by sanitation status within a city. We assessed how neighborhood levels of environmental fecal contamination (via spatially-representative sampling of open drains for E. coli) varied across four neighborhoods with varying income, type and coverage of household sanitation facilities, and population density in Accra, Ghana. Neighborhoods with very high sanitation coverage (≥89%) still had high (>4 log10 CFU/100 mL) E. coli concentrations in drains. Between-neighborhood variation in E. coli levels among the high coverage neighborhoods was significant: drain concentrations in neighborhoods with 93% and 89% coverage (4.7 (95% CI: 4.5, 4.9) & 4.9 (95% CI: 4.5, 5.3) log10 CFU/100 mL, respectively) were higher than in the neighborhood with 97% coverage (4.1 log10 CFU/100 mL, 95% CI: 3.8, 4.4 log10 CFU/100 mL). Compared with the highest coverage neighborhood, the neighborhood with lowest coverage (48%) also had higher E. coli concentrations (5.6 log10 CFU/100 mL, 95% CI: 5.3, 5.9 log10 CFU/100 mL). Although fecal contamination in open drains appeared lower in neighborhoods with higher onsite sanitation coverage (and vice versa), other factors (e.g. fecal sludge management, animals, population density) may affect drain concentrations. These results underscore that neighborhood-level onsite sanitation improvements alone may not sufficiently reduce fecal hazards to public health from open drains. These findings supporting the need for integrated, city-level fecal sludge management alongside multifaceted interventions to reduce fecal contamination levels and human exposure.

Bacterial metagenome analysis of Mytilus galloprovincialis collected from Istanbul and Izmir coastal stations of Turkey

Mytilus galloprovincialis is a marine mollusk belonging to the Bivalvia class. It has been distributed largely in Turkish shores and worldwide aquatic environments. Besides being known as an environmental pollution indicator, it is highly consumed as a food and has a high economic value. Due to their nutritional mechanisms by filtering water, they are affected by pollution in seawater and mussels can host-microbial diversity of environmental origin as well as pathogenic bacteria. Therefore, in this study, bacterial species found in Mediterranean mussels collected from the coastal stations of Istanbul [Rumeli Kavagi (RK), Kucukcekmece (KC)], and Izmir [(Foca (MF), Urla (MU)] were investigated and compared with microbiological and metagenomic analyses. According to microbiological analysis results, 34 mussel-associated Enterobacteriaceae and Vibrionaceae family members were identified. As a result of the culture-independent metagenomic analysis, taxonomic groups for each station were identified and compared based on Operational Taxonomic Unit data. For all stations, the most abundant bacterial genera were the unclassified bacterial genera. The total number of mussel-related total richness identified in all groups was 4889 (RK = 1605; KC = 1930; MF = 1508; and MU = 1125). According to the metagenomic data obtained in this study, different relative amounts of Lachnospiraceae and Bacteroidetes taxa groups were reported for all stations. The pathogenic bacterial genera identified by metagenomic analyses which may be significant for the public health are Arcobacter, Clostridium, Aeromonas, Vibrio, Escherichia_Shigella, Klebsiella, Campylobacter, Helicobacter, Pseudomonas, Morganella, Serratia, Corynebacterium, Enterococcus, Staphylococcus, Yersinia, Mycoplasma, Brucellaceae_unclassified, Pantoea, and Proteus.

Effects of improved water, sanitation, and hygiene and improved complementary feeding on environmental enteric dysfunction in children in rural Zimbabwe: A cluster-randomized controlled trial

BACKGROUND

Environmental enteric dysfunction (EED) may be an important modifiable cause of child stunting. We described the evolution of EED biomarkers from birth to 18 months in rural Zimbabwe and tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF), on EED.

METHODOLOGY AND FINDINGS

The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial was a 2x2 factorial cluster-randomised trial of improved IYCF and improved WASH on child stunting and anaemia at 18 months of age. 1169 infants born to HIV-negative mothers provided plasma and faecal specimens at 1, 3, 6, 12, and 18 months of age. We measured EED biomarkers that reflect all domains of the hypothesized pathological pathway. Markers of intestinal permeability and intestinal inflammation declined over time, while markers of microbial translocation and systemic inflammation increased between 1-18 months. Markers of intestinal damage (I-FABP) and repair (REG-1β) mirrored each other, and citrulline (a marker of intestinal epithelial mass) increased from 6 months of age, suggesting dynamic epithelial turnover and regeneration in response to enteric insults. We observed few effects of IYCF and WASH on EED after adjustment for multiple comparisons. The WASH intervention decreased plasma IGF-1 at 3 months (β:0.89, 95%CI:0.81,0.98) and plasma kynurenine at 12 months (β: 0.92, 95%CI:0.87,0.97), and increased plasma IGF-1 at 18 months (β:1.15, 95%CI:1.05,1.25), but these small WASH effects did not translate into improved growth.

CONCLUSIONS

Overall, we observed dynamic trends in EED but few effects of IYCF or WASH on biomarkers during the first 18 months after birth, suggesting that these interventions did not impact EED. Transformative WASH interventions are required to prevent or ameliorate EED in low-income settings.

The role of social identification for achieving an open-defecation free environment: A cluster-randomized, controlled trial of Community-Led Total Sanitation in Ghana

Unsafe sanitation practices are a major source of environmental pollution and are a leading cause of death in countries of the Global South. One of the most successful campaigns to eradicate open defecation is "Community-Led Total Sanitation" (CLTS). It aims at shifting social norms towards safe sanitation practices. However, the effectiveness of CLTS is heterogeneous. Based on social identity theory, we expect CLTS to be most effective in communities with stronger social identification, because in these communities individuals should rather follow social norms. We conducted a cluster-randomized controlled trial with 3,216 households in 132 communities in Ghana, comparing CLTS to a control arm. Self-reported open defecation rates and social identification were assessed pre-post. Generalized Estimating Equations showed that CLTS achieved lower open defecation rates compared to controls. This effect was significantly stronger for communities with stronger average social identification. The results confirm the assumptions of social identity theory. They imply that pre-existing social identification needs to be considered for planning CLTS, and strengthened beforehand if needed.

Exploring the complex relationship between women's sanitation practices and household diarrhea in the slums of Nairobi: a cross-sectional study

BACKGROUND

Diarrheal disease kills over half a million people each year in sub-Saharan Africa; the majority are children under 5 years. About 58% of diarrhea cases are associated with poor water, sanitation, and hygiene-a critical issue for people living in informal settlements. In Kenya, 60% of Nairobi's population lives in informal settlements; yet, there is a paucity of research exploring the relationship between water, sanitation and hygiene (WASH) conditions in these settlements and associated health outcomes.

METHODS

The study examines characteristics of women's WASH behaviors and environments as potential factors associated with household diarrhea in Mathare Valley Informal Settlement in Nairobi using cross-sectional survey data collected from 550 women.

RESULTS

Approximately 17% of participants reported that at least one member of the household suffered from diarrhea in the previous 2 weeks-48% of the cases were children under five. Results from a logistic regression exploring factors associated with reports of household diarrhea suggest that women's sanitation management strategies are associated with recent household diarrhea. Women who use toilets for defecation during the day, but rely on bags, buckets, or open defecation (OD) for urination during the day and for urination and defecation at night have over five time the odds of recent household diarrhea than women who use a toilet for all their sanitation needs. The odds of diarrhea were also higher for participants who walk up to 2 min to reach their toilets/sites for defecation and those who rely on water from taps inside buildings and plots. Odds were 62% lower for participants with clean toilets.

CONCLUSIONS

Findings suggest that health targets to reduce the prevalence of diarrheal diseases in informal settlements may not be met unless particular attention is paid to the needs of women living in these environments.

A Faecal Contamination Index for interpreting heterogeneous diarrhoea impacts of water, sanitation and hygiene interventions and overall, regional and country estimates of community sanitation coverage with a focus on low- and middle-income countries

OBJECTIVES

The impact on diarrhoea of sanitation interventions has been heterogeneous. We hypothesize that this is due to the level of prevailing faecal environmental contamination and propose a Faecal Contamination Index (FAECI) of selected WASH indicators (objective 1). Additionally, we provide estimates of the proportion of the population living in communities above certain sanitation coverage levels (objective 2).

METHODS

Objective 1: Faecal contamination post-intervention was estimated from WASH intervention reports. WASH indicators composing the FAECI included eight water, sanitation and hygiene practice indicators, which were selected for their relevance for health and data availability at study- and country-level. The association between the estimated level of faecal environmental contamination and diarrhoea was examined using meta-regression. Objective 2: A literature search was conducted to identify health-relevant community sanitation coverage thresholds. To estimate total community coverage with basic sanitation in low- and middle-income countries, at relevant thresholds, household surveys with data available at primary sampling unit (PSU)-level were analysed according to the identified thresholds, at country-, regional- and overall level.

RESULTS

Objective 1: We found a non-linear association between estimated environmental faecal contamination and sanitation interventions' impact on diarrhoeal disease. Diarrhoea reductions were highest at lower faecal contamination levels, and no diarrhoea reduction was found when contamination increased above a certain level. Objective 2: Around 45% of the population lives in communities with more than 75% of coverage with basic sanitation and 24% of the population lives in communities above 95% coverage, respectively.

CONCLUSIONS

High prevailing faecal contamination might explain interventions' poor effectiveness in reducing diarrhoea. The here proposed Faecal Contamination Index is a first attempt to estimate the level of faecal contamination in communities. Much of the world's population currently lives in faecally contaminated environments as indicated by low community sanitation coverage.