Download or read book Understanding Sources and Determinants of Fecal Contamination of Water Hands Food and Household Floors in Low income Countries written by Angela R. Harris and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Diarrheal disease is one of the leading causes of death in children under 5 years, causing approximately 0.8 million annual deaths globally. Almost 50% of these deaths come from Africa and 30% from Southeast Asia, where diarrheal diseases account for 11% of all child-deaths. Diarrheal pathogens are transmitted primarily through a fecal-oral route, with illness being predominately caused by ingestion of the pathogens from water, food, or hands, which have been contaminated by inadequate sanitation and hygiene. Additionally, contaminated surfaces can serve as a reservoir for fecal pathogens within the household. Fecal pathogens can come from both human and non-human, animal sources. In order to develop effective strategies to protect human health, understanding the levels of contamination on different surfaces or media in household environments is important. Furthermore, it is important to understand how the different vehicles of transmission (i.e., water, hands, food, floors) become contaminated; that is, identifying the sources of the fecal contamination and the behaviors and practices associated with contamination. In Tanzania, a structured observation study was conducted coupled with intensive sampling to measure levels of fecal contamination in drinking water to determine mechanisms for post-supply contamination of drinking water. The storage container and extraction methods were found to introduce fecal indicator bacteria in the stored water. Also, stored water quality and female caregiver hand contamination data from 1200 households in Tanzania was collected. Three different data-driven statistical methods, ordinary least squares regression, logistic regression, and classification tree, were used to explain variation of levels of contamination in stored water and female caregiver hands. Our study results highlight the complexity of predicting stored water quality and hand contamination. Despite using three different analytical techniques for modeling stored water quality and hand contamination, contamination was incorrectly predicted for a large fraction of samples. In rural Kenya and rural and urban Bangladesh, a validation of molecular microbial source tracking assays was conducted to determine if these techniques could be used on environmental samples to identify the human and animal sources of contamination. The human-specific assays performed well in the rural sites but the assays were not sensitive or specific in Dhaka, Bangladesh. The ruminant assay, BacR, performed well across all study sites, exhibiting high sensitivity and specificity. The Avian GFD assay was sensitive and specific in the rural sites, but was not specific in Dhaka, Bangladesh. Evidence of ruminant fecal contamination was found on household floors and child hand rinse samples in Dhaka, Bangladesh. Therefore, even in dense urban slums, the transmission pathway of ruminant feces should be considered in order to reduce contamination in household environments. Researchers should consider that non-host specific fecal indicator bacteria detected in environmental samples in these settings could be of animal origin. Finally, levels of fecal contamination on produce from neighborhood distribution markets and wholesale markets in Dhaka, Bangladesh were assessed. Fecal contamination, as measured by E. coli and enterococci, was found on carrots, eggplants, lal shak leaves, and tomatoes. Items from the neighborhood markets had higher levels of general fecal indicators than items from wholesale markets. The results of the study suggest that market-level mechanisms, such a vendor handling practices, could be influencing produce contamination. Evidence of fecal contamination from ruminants was also found on produce items, both from the wholesale and neighborhood distribution markets. Therefore, not only the pathway of human fecal contamination, but also that of animals, should be considered when developing interventions to reduce contamination on produce. This dissertation assesses the levels of fecal contamination in stored drinking water and on female caregiver hands in Tanzania, and of household floors, child hands, and vegetable produce in Bangladesh. The use of different models to explain variation of fecal contamination in water and on hands was explored. In addition, the dissertation evaluates the use of molecular techniques to identify the fecal source of contamination found in environmental samples in Kenya and Bangladesh. Data-driven understanding of the environmental conditions that are associated with fecal contamination will help inform studies to develop interventions and policies to protect human health. This dissertation work provides insight to the sources and correlates of fecal contamination of stored drinking water, female caregiver and child hands, household floors, and vegetable produce in low income countries. It also critically assesses methods for measuring and explaining fecal contamination in these setting.
Download or read book Childhood Exposure to Enteric Pathogens from Hands and Drinking Water in Tanzania written by Mia Catharine Morgan Mattioli and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2012, 6.6 million children died before reaching their fifth birthday. One in every ten of these deaths was the result of diarrheal disease, which causes some 1,800 under-5 deaths each day. Low-income countries bear a majority of the morbidity and mortality burden from childhood diarrhea, and the highest rates child diarrhea cases occur in sub-Saharan Africa. Transmission of diarrhea-causing pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Without knowing the relative contribution, it is challenging for policy makers and low-income country governments to efficaciously prioritize funding for water and hygiene based interventions. Using the sub-Saharan African town of Bagamoyo, Tanzania, as a case study, this dissertation aims to evaluate the relative contribution by characterizing the prevalence and drivers of childhood exposure to enteric pathogens and human feces by contaminated hands and stored water. The first research chapter of this dissertation (Chapter 2) examines the prevalence of enteric pathogens on mothers' hands, in community water sources, and in water stored in Tanzanian homes. In each sample type, the presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed. Culture-based fecal indicator bacteria (FIB) (E. coli and enterococci) and turbidity of water and hand rinses were also measured. The relationship between water and hand pathogen contamination, as well as the association between different water source or sanitation infrastructure and pathogen contamination, was examined. Finally, the ability of FIB and turbidity to serve as predictors of pathogen contamination in water and on hand was assessed. The occurrence of ECVG was equivalent across all sample types. ECVG were more likely to be found in unimproved water sources, but both ECVG and viral genes were detected in improved water sources. ECVG were more likely found in stored water of households with unimproved sanitation facilities. FIB and turbidity were good predictors of ECVG presence, whereas turbidity and human-specific Bacteroidales were good predictors of viruses. The results provide insights into the distribution of pathogens in Tanzanian households and offer evidence that both hand washing and improved water management practices could alleviate viral and bacterial diarrhea. Hands as vectors of enteric viruses are investigated further in Chapter 3 by evaluating norovirus contamination on hands of Tanzanian mothers during the rainy and dry seasons. Norovirus was chosen because it is the most common cause of viral gastroenteritis worldwide and one of the leading causes of viral diarrhea in children under age five. Norovirus GII was detected in approximately five percent of hand rinse samples during both the rainy and dry seasons, suggesting that mothers' hands serve as a source of norovirus exposure for young children in Tanzanian households. Levels of FIB (E. coli and enterococci) were not associated with norovirus hand contamination. Turbidity was found to be associated with norovirus presence on mother's hands; however, this relationship was only observed during the rainy season. Further research is needed to determine consistent indicators for norovirus contamination. In particular, future work should evaluate whether human-specific Bacteroidales may serve as a more consistent indicator for norovirus presence on hands in Tanzania. Chapter 4 builds on the characterization of enteric pathogen exposure from water and hands in Chapter 2 by exploring the association between pathogen contamination and the presence of a sick child in the home. The overall prevalence of enteric pathogen genes and the Bacteroidales human specific fecal marker found in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. However, better stored water quality was found among households with diarrhea, suggesting that caregivers with sick children may be more likely take steps to improve water quality of stored water in the home. In order to further evaluate this conclusion, Chapter 4 also examines the association between enteric pathogen contamination and water management and hygiene behaviors. Mothers who had recently contacted food or water were more likely to have detectable levels of ECVG or human feces on their hands; while mothers who used reportedly less water for hand washing were less likely to have enteric viruses (rotavirus, enterovirus, or adenovirus) on their hands. Enteric virus and human fecal molecular markers were more likely found in the stored drinking water of households in which the markers were also detected on hands. Stored water collected from an improved source was less likely to have ECVG or human fecal contamination, and households using improved sanitation facilities were less likely to have ECVG contaminated stored water. Together the results of the water and hygiene behavior models suggest that interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment. In addition, use of improved water sources and sanitation facilities may help to reduce contamination of household stored drinking water. The final research chapter of the dissertation (Chapter 5) examines the relative contribution of hands and water to a Tanzanian child's daily fecal exposure using water and hand FIB data and a stochastic modeling approach. The results of the model show that Tanzanian children under the age of five ingest a significantly greater amount of human feces each day from hand-to-mouth contacts than from drinking household stored water. These results can help explain why interventions focused on water without also addressing hygiene often yield little or no effect on reported incidence of diarrhea in some settings. By simulating exposure separately for each United States Environmental Protection Agency (EPA) age risk category under the age of five, the model is able to show that hands, compared to water, are particularly important for children in their first six months of life. Therefore, interrupting the transmission of enteric pathogens from hands for this age group may have long-term growth and cognitive benefits. Overall, the model framework can aid policy makers and governments in the allocation of WASH funding for the reduction of childhood diarrhea by allowing them to evaluate the relative contribution of fecal exposure pathways within sub-Saharan African homes. The research in this dissertation combines tools from microbiology, engineering, and epidemiology to characterize pathogen exposure to children by contaminated hands and stored drinking water in a low-income country. This dissertation provides insights into the sources of a child's exposure to diarrhea-causing pathogens in the household environment and can inform debates about efficacious ways to reduce the burden of childhood diarrheal disease in low-income countries. Specifically, the results of this work highlight the important role that hands play in the exposure of young children to diarrhea-causing pathogens. As such, hygiene education and promotion, as well as providing enough water for proper hand hygiene, should be a priority for policy makers. In addition, the results of this work demonstrate the need for investments in improved sanitation infrastructure to reduce the high levels of fecal contamination in the environments of young children living in low-income countries.
Download or read book Microbial Source Tracking written by Jorge W. Santo Domingo and published by Emerging Issues in Food Safety. This book was released on 2007 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a state-of-the-art review of the current technology and applications being utilized to identify sources of fecal contamination in waterways. - Serves as a useful reference for researchers in the food industry, especially scientists investigating etiological agents responsible for food contamination. - Provides background information on MST methods and the assumptions and limitations associated with their use. - Covers a broad range of topics related to MST, including environmental monitoring, public health and national security, population biology, and microbial ecology. - Offers valuable insights into future research directions and technology developments.
Download or read book Global Issues in Water Sanitation and Health written by Institute of Medicine and published by National Academies Press. This book was released on 2009-10-25 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the human population grows-tripling in the past century while, simultaneously, quadrupling its demand for water-Earth's finite freshwater supplies are increasingly strained, and also increasingly contaminated by domestic, agricultural, and industrial wastes. Today, approximately one-third of the world's population lives in areas with scarce water resources. Nearly one billion people currently lack access to an adequate water supply, and more than twice as many lack access to basic sanitation services. It is projected that by 2025 water scarcity will affect nearly two-thirds of all people on the planet. Recognizing that water availability, water quality, and sanitation are fundamental issues underlying infectious disease emergence and spread, the Institute of Medicine held a two-day public workshop, summarized in this volume. Through invited presentations and discussions, participants explored global and local connections between water, sanitation, and health; the spectrum of water-related disease transmission processes as they inform intervention design; lessons learned from water-related disease outbreaks; vulnerabilities in water and sanitation infrastructure in both industrialized and developing countries; and opportunities to improve water and sanitation infrastructure so as to reduce the risk of water-related infectious disease.
Download or read book Animal Waste Water Quality and Human Health written by A. Dufour and published by IWA Publishing. This book was released on 2012-10-14 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Domestic animals contaminate recreational waters and drinking-water sources with excreta and pathogens; but this threat to public health is inadequately understood and is insufficiently addressed in regulations. More than 85% of the world’s faecal wastes is from domestic animals such as poultry, cattle, sheep and pigs. These animals harbor zoonotic pathogens that are transported in the environment by water, especially runoff. However little information exists on health effects associated with exposure to this potential hazard to human health; and water standards focused on control of human fecal contamination do reflect the contribution of non-human fecal contamination to risk. Does compliance with current monitoring practices using microbial indicators provide protection against animal and bird sources of fecal contamination? Prepared with contributions from a group of international experts, Animal Waste, Water Quality and Human Health considers microbial contamination from domestic animal and bird sources and explores the health hazards associated with this microbial contamination and approaches to protecting public health. Animal Waste, Water Quality and Human Health will be of interest to regulators with responsibility for recreational waters, drinking water quality and water reuse; policymakers working in water quality, public health and agriculture; decision makers responsible for livestock management; and scientists and practitioners concerned with many affected subjects. Topics covered include: Credible waterborne zoonotic pathogens are discussed and ranked according to their potential hazard level. Each pathogen is described with regard to their sources, reservoirs, and infectivity. Faecal production rates of various domestic animals are discussed, alongside pathogen transmission in animal populations, pathogen prevalence in animals and “supershedders”. Transport of fecal indicator organisms and their episodic occurrence in catchments. Interventions for improving food safety and reducing production losses. The impact of interventions, e.g. enhanced attenuation and storage to prevent spills; benchmarking against best management practices to reduce diffuse source contamination. Models to inform design of farm-scale best management practices and the effectiveness of best management practices for attenuating pathogen transport within catchments. The complex nature of human exposure to zoonotic waterborne pathogens; including the relationships among livestock waste contamination, water impairment, zoonotic pathogens, and human infection and illness. Human exposure interventions include case studies that discuss eradicating disease in discharging populations, adding filtration to minimal treated water to reduce Cryptosporidium occurrence and UV disinfection of beach waters to reduce beach postings. Indicators, sanitary surveys and source attribution techniques; risk assessment of exposure to zoonotic pathogens, including an interactive risk comparison approach. A review of epidemiological studies that address the relationship between swimmer illness and exposure to waters contaminated by nonhuman fecal wastes. Economic evaluation of the costs and benefits associated with animal waste management and human health.
Download or read book Monitoring Bathing Waters written by Jamie Bartram and published by CRC Press. This book was released on 1999-11-25 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, which has been prepared by an international group of experts, provides comprehensive guidance for the design, planning and implementation of assessments and monitoring programmes for water bodies used for recreation. It addresses the wide range of hazards which may be encountered and emphasizes the importance of linking monitoring progra
Download or read book Guidelines for Drinking water Quality written by World Health Organization and published by World Health Organization. This book was released on 1993 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume describes the methods used in the surveillance of drinking water quality in the light of the special problems of small-community supplies, particularly in developing countries, and outlines the strategies necessary to ensure that surveillance is effective.
Download or read book Elucidating Pathways of Fecal Exposure written by Laura Hsi Kwong and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Causing nearly 0.5 million deaths in 2015, diarrhea is the second-leading cause of death among children between 1-59 months of age. Diarrhea is most often caused by pathogens transmitted through fecal-oral pathways: ingestion of fecally contaminated water, food, and soil or mouthing of contaminated hands and objects. Fecal contamination transmitted along these pathways, in combination with malnutrition, may also cause environmental enteropathy, a sub-clinical condition of the intestine. As with diarrhea, environmental enteropathy may result in malnutrition and stunting, which have long-term adverse effects on cognitive development and productivity in adulthood. Despite these concerns, the predominant pathway(s) of fecal matter transmission are poorly understood. Research into the relative contribution of each pathway to total ingestion of feces would help guide interventions to reduce fecal exposure. The research presented in this dissertation uses data on children's detailed interactions with the environment, combined with data on fecal contamination of various environmental reservoirs, to estimate the relative contribution of each pathway to children's total fecal ingestion. All four studies in this dissertation were carried out in the same rural communities in Bangladesh. In the first of two studies characterizing children's contacts with the environment, I conducted a structured observation of 149 children ages 3-18 months old. I detailed the frequency of children's hand-to-mouth and object-to-mouth contacts and recorded the prevalence and frequency of children's direct ingestion of soil and feces. I found that hand- and object-mouthing are frequent and higher than those documented for children in the U.S. These results suggest that, when assessing the environmental exposure faced by children in rural, low-income settings such as Bangladesh, the use of exposure data from children in the U.S. may underestimate risk. In the second study, I conducted video observations annually for three years to evaluate how children's environmental exposures change as they age. I captured the frequency, duration, and sequence of hand-to-mouth, object-to-mouth, and hand-to-object contacts of children 3-47 months old. Using the resulting longitudinal data in a random-effects model, I found that children's hand-to-mouth and object-to-mouth contact frequencies were associated with neither child age nor location of play, and that the mouthing frequencies of individual children are not correlated over time. In a third study, I combined the data from these observational studies with data on the amount of soil on hands and objects to model the quantity of soil ingested by children in rural Bangladesh. Estimated soil ingestion among children in rural Bangladesh was in the high end of the range of soil ingestion estimates for children living in high-income countries. The quantity of soil ingested was driven by direct ingestion of soil, mouthing of hands while not eating, and mouthing of objects. These results suggest that interventions to reduce fecal-oral disease should focus on preventing the direct ingestion of soil and improving children's hand hygiene. In the final study of this dissertation, I modeled the total ingestion of fecal matter by children in rural Bangladesh, including transmission through mouthing of hands and objects, as well as ingestion of food, water, soil, and feces. Children 6-23 months old ingest more fecal matter than children
Download or read book Meeting the MDG Drinking Water and Sanitation Target written by World Health Organization and published by . This book was released on 2004 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of safe drinking water and hygienic sanitation facilities is a precondition for health and for success in the fight against poverty, hunger, child deaths and gender inequality. In adopting the Millennium Development Goals, the countries of the world pledged to reduce by half the proportion of people without access to safe drinking water and basic sanitation. With the exception of sub-Saharan Africa, the world is well on its way to meeting the drinking water target by 2015, but progress in sanitation is stalled in many developing regions . This report provides the latest estimates and trends on where we stand today.--Publisher's description.
Download or read book Do Sanitation Improvements Reduce Fecal Contamination of Water Hands Food Soil and Flies Evidence from a Cluster Randomized Controlled Trial in Rural Bangladesh written by Ayse Ercumen and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Health in Humanitarian Emergencies written by David Townes and published by Cambridge University Press. This book was released on 2018-05-31 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive, best practices resource for public health and healthcare practitioners and students interested in humanitarian emergencies.
Download or read book Sanitation Safety Planning written by World Health Organization and published by World Health Organization. This book was released on 2015-08-06 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Sanitation Safety Planning (SSP) is a step-by-step risk based approach to assist in the implementation of the 2006 WHO Guidelines for Safe Use of Wastewater, Excreta and Greywater in Agriculture and Aquaculture. The approach can be applied to all sanitary systems to ensure the system is managed to meet health objectives. SSP assists users to: systematically identify and manage health risk along the sanitation chain; guide investment based on actual risks, to promote health benefits and minimize adverse health impacts; provide assurance to authorities and the public on the safety of sanitation-related products and services. The SSP manual is targeted at a variety of users at different levels including; health authorities and regulators, local authorities, wastewater utility managers, sanitation enterprises and farmers, community based organizations, farmers associations and NGOs. SSP brings together actors from different sectors to identify health risks in the sanitation system and agree on improvements and regular monitoring and underscores the leadership role of the health sector."--Publisher's description.
Download or read book Tracking the Effect of Improved Community Sanitation Coverage in Rural Odisha India Using Molecular Methods written by Mitsunori Odagiri and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In India, over 600 million people practice open defecation, in particular in rural areas, and over 500,000 children under the age of five die every year due to diarrhea. A better understanding of human and animal fecal exposure pathways is necessary to design and deliver effective water, sanitation and hygiene (WASH) interventions in communities. Microbial source tracking (MST) techniques based on host-associated Bacteroidales genetic markers coupled with direct pathogen measurement were applied in rural communities in India where open defecation is common and animal fecal loading is high. In a validation study, ten candidate Bacteroidales quantitative PCR (qPCR) assays were tested against human and other animal fecal samples collected in coastal Odisha, India prior to application in the field. The most suitable set of MST assays to track human and livestock-derived fecal contamination in Odisha, India, was identified based on testing results. Next, human and livestock animal fecal contamination together with locally important enteric pathogen contamination (i.e., rotavirus, adenovirus, Vibrio cholerae, pathogenic Escherichia coli, Cryptosporidium and Giardia) was assessed in a cross-sectional study of 60 villages of a cluster-randomized controlled sanitation trial in Odisha, India, using the previously validated host-associated MST and pathogen assays. Contamination rates in 30 intervention villages (functional sanitation coverage: 38%) were compared to 30 control villages (functional sanitation coverage: 10%). Widespread human fecal contamination in households was observed, while animal fecal contamination was prevalent in public ponds and homes. More than 30% of tubewells and about 90% of public ponds we sampled were positive for at least one of five pathogens measured. There was no evidence that the intervention reduced human fecal exposure in any tested pathway, nor the prevalence of pathogens in water sources. Finally, sources and mechanisms of fecal and pathogen contamination in ground drinking water sources and public ponds were investigated with empirical modeling techniques based on GPS locations of human and animal fecal sources, climatic data, and characteristics of water sources. The study found a possible negative impact of leaching from nearby latrines on the water quality of private (shallow) tubewells, while missing well casing significantly increases risks of fecal and pathogen contamination of public (deep) tubewells in the communities. Animal fecal loadings especially from cattle were also found to be a potential source of fecal contamination in ground drinking water sources and public ponds in these settings. The present study is the first to investigate human and animal fecal and pathogen contamination pathways together with the effect of increased improved sanitation coverage using host-associated Bacteroidales assays in a middle-income country where open defecation is widespread and livestock animal rates are high. It illustrates that both human and animal fecal exposures need to be reduced in households in these settings. Furthermore, sanitation interventions should be carefully implemented to minimize a potential negative impact on shallow ground water sources together with better animal excreta management to achieve health gains. Lastly, the findings emphasize the value of fecal source identification to shed light on complicated diarrheal disease transmission pathways and to design and deliver effective water, sanitation and hygiene interventions in low- and middle-income settings where diarrheal disease burdens are high and contamination of mixed human and animal origins is prevalent.
Download or read book Progress on Drinking Water and Sanitation written by WHO/UNICEF Joint Water Supply and Sanitation Monitoring Programme and published by World Health Organization. This book was released on 2014-07-18 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Even though progress towards the MDG target represents important gains in access for billions of people around the world, it has been uneven. Sharp geographic, sociocultural and economic inequalities in access persist and sometimes have increased. This report presents examples of unequal progress among marginalized and vulnerable groups. Section 1 presents the status of and trends in access to improved drinking water sources and sanitation. Section 2 provides a snapshot of inequalities in access to improved drinking water sources and sanitation. Section 3 presents efforts to strengthen monitoring of access to safe drinking water and sanitation services under a post-2015 development agenda, as well as the challenges associated with these efforts."--Publisher's website.
Download or read book Slums of Urban Bangladesh written by University of Dhaka. Centre for Urban Studies and published by . This book was released on 2006 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Closing the Loop written by Steven A. Esrey and published by . This book was released on 2001 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
