Dissertations / Theses on the topic 'Waterborne diseases'

Thesis (Ph.D.)--Boston University
The resurgence of infectious diseases and global climate change's potential impact on them has refocused public health's attention on the environment's role in infectious disease. The studies in this dissertation utilize the increased availability of satellite image-derived data sets with fine temporal and geographic granularity and the expansion of epidemiologic methods to explore the relationship between the environment and infectious disease in three settings. The first study employed a novel study design and analytic methods to investigate the hypothesis that heavy rainfall is an independent risk factor for waterborne disease outbreaks (WBDOs). We found that a location experiencing a heavy rainfall event had about half the odds of a WBDO two or four weeks later than did a location without a heavy rainfall event. The location-based case-crossover study design utilized in this study may help to expand the research methods available to epidemiologists working in this developing field. The second study employed a location-based case-crossover study design to evaluate standardized differences from historic average of weekly rainfall in locations with a recorded introduction of Ebola into a human. For each 1.0 unit z-score decrease in total rainfall, the odds of an Ebola introduction three weeks later increased by 75%. Given the severity of Ebola outbreaks and the dearth of knowledge about indicators of increased risk, this finding is an important step in advancing our understanding of Ebola ecology. The third study used GIS methods on remote sensing data to estimate the association between peridomestic forest/non-forest interface within 100, 150, 250 meters and Lyme-associated peripheral facial palsy (LAPFP) among pediatric facial palsy patients. After adjustment for sex, age, and socio-economic status, children with the highest level of forest edge in the three radii of analysis had 2.74 (95% CI 1.15, 6.53), 4.58 (1.84, 11.41), and 5.88 (2.11, 16.4) times the odds of LAPFP compared to children with zero forest edge in those radii. This study is the first to examine environmental risk factors for LAPFP. Each of these studies advances the techniques used to investigate environmental risk factors for infectious disease through study design, case definition, data used, or exposure definitions.

Poor sanitation, unhygienic practices and close living associations between people and animals in rural communities increase the risk of zoonoses and add to faecal contamination of stored drinking water. Point-of-use interventions can improve the microbiological quality of household drinking water and a combination of microbial and chemical indicator tests could identify the origin of faecal pollution. The improvement of the microbiological quality of drinking water in rural households by the implementation of intervention strategies which included the use of traditional storage containers as well as an improved safe storage container (CDC, USA), with or without the addition of a sodium hypochlorite solution were determined. The origin of faecal contamination in the water sources and household stored water were determined using male specific F-RNA subgroup genotyping. This study attempted to assess the survival of indicator microorganisms and selected bacterial pathogens and viruses in the improved safe storage container in borehole and river water samples. An intervention study was conducted in two rural villages utilising different source water. Results indicated that the improved safe storage container without the addition of a stabilized sodium hypochlorite solution did not improve the microbiological quality of the stored drinking water and had counts of indicator microorganisms similar to that found in the traditional storage containers. However, the households using the 1% and the 3.5% sodium hypochlorite solutions have shown an effective reduction in the counts of indicator microorganisms in both the traditional and the improved safe storage containers. The compliance with the use of the sodium hypochlorite interventions ranged between 60% and 100%, which was in agreement with similar studies carried out in other developing countries. One village complied with the intervention while the other village did not. Reasons for this included financial factors, an unsupportive infrastructures and lack of education and knowledge on health risks by the households. Male specific F-RNA bacteriophage genotyping showed that faecal contamination in the water source samples and both the traditional and improved safe storage containers at the point-of-use were primarily of animal origin (Subgroup I). Households using river water had subgroup II F-RNA bacteriophages present in the stored household water, which was associated with human faecal pollution. However, subgroup II F-RNA bacteriophages has been isolated from faeces of cattle and poultry, which indicated that F-RNA subgroup typing might not be a specific tool to determine the origin of faecal pollution in water sources. Laboratory seeding experiments indicated that 1% sodium hypochlorite solution were less effective in reducing heterotrophic bacteria, Escherichia coli, Salmonella typhimurium, Clostridium perfringens, F-RNA bacteriophages and coxsackie B1 virus counts in the improved safe storage containers filled with river water with a high turbidity. However, the 1% sodium hypochlorite solution did reduce the indicator and seeded microorganisms within 60 min in containers filled with borehole water with a low turbidity. The 3.5% sodium hypochlorite solution effectively decreased the numbers of microorganisms to undetectable limits within 60 min in both the borehole and river filled storage containers irrespective of the turbidity values. This study has showed that a combination of intervention strategies can provide rural communities with microbiologically safe drinking water.
Thesis (PhD (Medical Virology))--University of Pretoria, 2008.
Medical Virology
PhD
unrestricted

>Magister Scientiae - MSc
Despite the wide success of antimicrobial agents against waterborne pathogens, waterborne disease continues to pose a threat to both mankind and animals. A major concern is that certain bacteria have developed resistance to antimicrobial agents, as a result of their overuse. Silver (Ag) nanoparticles are widely used for antibacterial purposes such as medical dressings. However, they are highly toxic to human cells. Hence, there is a great interest in developing next generation antibacterial nanoparticles that are as effective as Ag nanoparticles for antibacterial functions, while having less toxicity to human cells. Several methods can be used to generate these antimicrobial nanoparticles, one of which is green nanotechnology. Green nanotechnology uses natural plants such as tea to synthesise nanoparticles rather than chemicals, thus reduce human and animal harm and improve sustainability of antibacterial agents. Silver-titanium nano-composites (Ag-TiO2 NCs) were synthesised with the hydrothermal method using a tea extract from Aspalathus linearis (Rooibos, RB), and distilled water in the presence of nitrogen. The resulting structures were characterised with high resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS) analysis X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). The antibacterial characteristics of these new NCs were evaluated against 3 bacteria: Bacillus cereus, Cupriavidus metallidurans, and Escherichia coli. The optimum processing conditions to produce 6-nm spherical NPs included maintaining the temperature at 90 °C, the pH at 4.35, and using RB extract at a concentration of 2 mg/mL. The size of silver NPs was reduced in acidic conditions, agglomerated in neutral conditions, and highly reduced in alkaline conditions. Increasing the pH decreased the particle size and narrowed the particle size distribution. Gram-positive B. cereus showed slight resistance or tolerance to the Ag-TiO2 nanocomposite compared to the gram-negative bacteria E. coli and C. metallidurans. The treatment concentration required for total inhibition of E. coli and C. metallidurans growth was 100 mg/mL. Supported silver nanoparticles has shown to be a suitable way to obtain highly dispersed silver over higher surface area. This approach allowed Ag-TiO2 nanocomposite to be an efficient bactericide, with less silver amount employed.

Clean drinking and recreational water is essential for human survival and contaminated water cause 1.4 million deaths worldwide every year. Both developing and developed countries suffer as a consequence of unsafe water that cause waterborne diseases. The Great Lakes region, located in the United States is no exception. Climate change is predicted to cause an increase in waterborne disease outbreaks, worldwide, in the future. To adapt to this public health threat, vulnerability assessments are necessary. This literature study includes a vulnerability assessment that describes the main factors that affect the spreading of waterborne diseases in the Great Lakes region. Future climate scenarios in the region, and previous outbreaks are also described. The study also includes a statistical analysis where mean temperature and precipitation is plotted against waterborne disease cases. The main conclusion drawn is that the Great Lakes region is at risk of becoming more vulnerable to waterborne diseases in the future, if it does not adapt to climate change.

Nucleic acid hybridization (gene probe) and polymerase chain reaction (PCR) techniques have been used to detect viral nucleic acid in water. However, gene probe and PCR may not distinguish between infectious and noninfectious viruses. This study evaluated the ability of gene probe to detect viable poliovirus 1 (polio 1), from sterile and nonsterile groundwater, and the ability of PCR to detect infectious human immunodeficiency virus (HIV-1) from tap and wastewater. The plaque forming (BGM cells), and the tissue culture infectious dose fifty (TCID₅₀) (PLC/PRF/5 cells) procedures were used to detect infectious polio 1 and HIV-1, respectively. Detection of polio 1 by gene probe and cell culture was similar in nonsterile water and in filter sterilized water, but not in autoclaved water. These results suggest that in some natural waters, detection of polio 1 by gene probe may correlate to detection by cell culture procedures. Although detection of infectious HIV-1 by cell culture decreased gradually, until no virus could be found, detection by PCR remained positive throughout the study. Therefore, it was concluded that the use of PCR to assess the risk associated to the presence of HIV-1 in polluted waters, may not be adequate. The enteric adenovirus types 40 (Ead 40) and 41 (Ead 41) are considered the second most important cause of viral gastroenteritis in children, but their role as waterborne pathogens is uncertain. This study compared the survival of Ead 40 and Ead 41 with polio 1, and hepatitis A virus (HAV) in different types of water. The Enteric adenoviruses survived longer in tap and sea water than either polio 1 or HAV, but only slightly better in wastewater. These results suggest that the enteric adenoviruses may survive for prolonged periods in water, representing a potential route of transmission. This study evaluated also the concentration of Ead 40 by the filter adsorption-elution method. With negatively-charged filters, recovery efficiencies of 22, 36, and 38% were obtained from secondary sewage, tap and sea water, respectively. Using electropositive filters, Ead 40 was recovered from tap water with an efficiency of 26.5%. These results show that Ead 40 can be concentrated, from water, with an efficiency comparable to that of other enteric viruses.

>Magister Scientiae - MSc
Water is essential for life, yet access to safe drinking water is still a major concern worldwide due to waterborne diseases. The current study proposes silver nanoparticles (AgNPs) as an antibacterial agent. Silver nanoparticles were synthesised using different reductants and stabilisers, and the resulting structures were characterised with Ultra-violet visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) analysis. The antibacterial properties of the AgNPs were tested against a panel of 5 indicator organisms: Cupriavidus metallidurans, Staphylococcus epidermidis, Mycobacterium smegmatis, Bacillus cereus and a multi-drug resistant Escherichia coli 1699. Spherical AgNPs that absorbed at around 400 nm, with diameters ranging between 18.8-26.4 nm or 5.4-13.1 nm were prepared by ascorbic acid or sodium borohydride respectively. The optimum processing conditions that produced 6±1.8 nm spherical nanoparticles included maintaining the temperature at 0 ⁰C, the pH at 9.78 and the NaBH4/Ag/PVP ratio at 16:1:10. Exposing AgNPs to light for 6 hours did not alter the particle size rather it changed the particles shape from spherical to icosahedral. Stirring caused particles to agglomerate, however, no agitation resulted in the formation of irregular structures of different sizes. Sensitivity to the AgNPs ranged between 25 % and 100 % reduced bacterial growth depending on the strains used and the concentration of the AgNPs. The Gram negative bacteria were more sensitive to AgNPs than Gram positive bacteria. However silver ions were more toxic than AgNPs for all but one of the strains tested, B. cereus was completely resistant to both Ag+ and AgNPs. C. metallidurans and E.coli (1699) showed a dose dependent sensitivity to AgNPs and the minimum inhibitory concentrations were established at 50 and 20 mg/L AgNPs respectively. C. metallidurans and E.coli (1699) were also eradicated by 10 mg/L Ag+. The E. coli TEM images showed accumulation of AgNPs within the cells, cell shrinking and leakage of cellular components. This suggests that AgNPs have a similar toxicity effect on bacterial cells as Ag+.

Thesis (PhD)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Water-borne infections have been a menace in many countries around the globe, claiming millions of lives. Cholera in particular has spread to all continents and now on its seventh epidemic. Although control measures have been continually developed through sanitation, vaccination and rehydration, the infection still devastates populations whenever there is an outbreak. In this research work, mathematical models for cholera transmission dynamics with focus on the impact of sanitation and hygiene, metapopulation spread, optimal control and biological control using a bacteriophage specific for pathogenic Vibrio cholerae are constructed and analysed. Vital analyses for the models are precisely given as well as numerical results depicting long term behaviour and the evolution of populations over time. The results of our analysis indicate that; improved sanitation and hand-hygiene are vital in reducing cholera infections; the spread of disease across metapopulations characterised by exchange of individuals and no cross community infection is associated with synchronous fluctuation of populations in both adjacent communities; during control of cholera, the control measures/efforts ought to be optimal especially at the beginning of the epidemic where the outbreak is often explosive in nature; and biological control if well implemented would avert many potential infections by lowering the concentration of pathogenic vibrios in the aquatic environment to values lower than the infectious dose.
AFRIKAANSE OPSOMMING: Water-infeksies is ’n bedreiging in baie lande regoor die wêreld en eis miljoene lewens. Cholera in die besonder, het op sy sewende epidemie na alle kontinente versprei. Hoewel beheermaatreëls voortdurend ontwikkel word deur middel van higiëne, inentings en rehidrasie, vernietig die infeksie steeds bevolkings wanneer daar ’n uitbraak voorkom. In hierdie navorsingswerk, word wiskundige modelle vir cholera-oordrag dinamika met die fokus op die impak van higiëne, metabevolking verspreiding, optimale beheer en biologiese beheer met behulp van ’n bakteriofaag spesifiek vir patogene Vibrio cholerae gebou en ontleed. Noodsaaklike ontledings vir die modelle is gegee sowel as numeriese resultate wat die langtermyn gedrag uitbeeld en die ontwikkeling van die bevolking oor tyd. Die resultate van ons ontleding dui daarop dat; verbeterde higiëne is noodsaaklik in die vermindering van cholera infeksies; die verspreiding van die siekte oor metapopulaties gekenmerk deur die uitruil van individue en geen kruis gemeenskap infeksie wat verband houmet sinchrone skommeling van bevolkings in beide aangrensende gemeenskappe; tydens die beheer van cholera,behoort die beheermaatreëls/pogings optimaal te wees veral aan die begin van die epidemie waar die uitbreking dikwels plofbaar in die natuur is; en biologiese beheer, indien dit goed geïmplementeer word, kan baie potensiële infeksies voorkom deur ’n vermindering in die konsentrasie van patogene vibrio in die water tot waardes laer as die aansteeklike dosis.

A contaminação de água subterrânea por coliformes fecais em propriedades rurais está diretamente relacionada com o saneamento básico rural oferecido, assim como as doenças de veiculação hídrica contraídas por essas populações. Esta pesquisa analisa a contaminação da água de consumo humano proveniente de poços, considerando os índices de potabilidade descritos na Portaria do Ministério da Saúde nº 2.914 e na Resolução CONAMA nº 398. Tem-se como estudo de caso uma área rural no município de Caxias do Sul, estado do Rio Grande do Sul, inserida na da bacia hidrográfica do arroio Marrecas. Foram realizados estudos por meio de informações contidas em relatórios técnicos, normatizações federais e bibliografias especializadas, para contextualização, conceituação e teorização de saneamento básico rural, qualidade e contaminação da água subterrânea, doenças de veiculação hídrica e poços. Mediante o uso do estimador de densidade Kernel, levantou-se o número de residências a serem entrevistadas. Durante o processo de entrevistas, averiguou-se a existência de saneamento básico rural nas propriedades, porém a maioria dos poços não estavam protegidos do acesso e/ou de serem contaminados por animais. Isto justificou a necessidade de realização de análise da qualidade da água subterrânea consumida por meio de poços particulares. Os resultados das entrevistas diagnosticaram uma população ambientalmente consciente sobre a preservação do meio e sobre a qualidade da água consumida. Contudo, os resultados das análises indicaram que a água ingerida estava contaminada por coliformes, assim como também houve relatos de doenças de veiculação hídrica, confirmando o saneamento deficiente em algumas propriedades rurais.
The contamination of groundwater by fecal coliforms in rural properties is directly related to the available basic rural sanitation, as well as to water-borne diseases contracted by these populations. This research analyzes the contamination of potable well water, applying the potability indicators described in the Ministry of Health Directive Nº. 2914 and the Brazilian Environment Council (CONAMA) Resolution No. 398. A rural area in the city of Caxias do Sul, Rio Grande do Sul, located within the hydrographic basin of the Marrecas stream, was used as the case study. Studies were conducted by using information contained in technical reports, federal guidelines, and specialized bibliographies, for the context, concepts and of basic rural sanitation, quality and contamination of groundwater, waterborne diseases and wells. The number of households to be interviewed was determined by using the Kernel density estimator. During the interview process, the existence of basic rural sanitation was verified in the properties, however, a majority of the wells were not protected from the access and/or from being contaminated by animals. This justified the need for conducting the analysis of the quality of groundwater consumed by way of individual wells. The interviews resulted in the diagnostic of an environmentally conscious population, aware of preserving the environment and of the quality of water consumed. However, the results of the analyses indicated that the drinking water was contaminated by coliforms, and there were also reports of waterborne diseases, confirming the poor sanitation in some rural properties.

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This study aims to analyze the conditions of water resources; sanitation and occurrence of waterborne diseases in districts of Águas Negras and Paracuri in Belém do Pará. As part of this study, the literature survey was conducted to benchmark theoretical, the Geography of Health, the importance of water resources for humans, sanitation of waterborne and location of the study area diseases. For the preparation of statistical data relating to sanitation and waterborne diseases in Brazil, in the state of Pará in Belém and information from official bodies such as the Brazilian Institute of Geography and Statistics (IBGE), Ministry of Health and were collected Department of Public Health (SESPA). The application of fifty questionnaires found that the socio economic, sanitation and waterborne diseases conditions, with residents was also conducted. It is concluded that the basic sanitation in Brazil is still very poor, especially in the North and Northeast; it directly influences the number of notifications of waterborne diseases in the country. In the neighborhoods of Paracuri and blackwater, by analyzing the interviews that there is a lack of sewage collection and treatment, regular water connections incidence of waterborne diseases causing large number of hospitalizations
de veiculação hídrica e da localização da área de estudo. Foram também analisados os dados estatísticos referentes ao saneamento básico e das doenças de veiculação hídrica no Brasil, no Estado do Pará e em Belém, cujas informações foram coletadas de órgãos oficiais, como o Instituto Brasileiro de Geografia e Estatística (IBGE), Ministério da Saúde e da Secretaria de Saúde Pública do Pará (SESPA). Foi realizada ainda a aplicação de cinquenta questionários, visando analisar as condições sócio econômicas, de saneamento e das doenças de veiculação hídrica, junto dos moradores. Conclui-se que o saneamento básico no Brasil ainda é muito deficiente, principalmente nas Regiões Norte e Nordeste, com isso influenciando diretamente, o grande número de notificações de doenças de veiculação hídrica no país. Nos bairros dos Paracurí e de Águas Negras, a partir da análise das entrevistas, observa-se que há falta de coleta e tratamento de esgoto, de ligações regulares de água, com a incidência de doenças de veiculação hídrica ocasionando grande número de internações

Orientador: Juliana Heloisa Pinê Américo-Pinheiro
Resumo: A água é componente de todos os processos vitais dos organismos, ao mesmo tempo em que pode carrear microrganismos, diluir soluções de qualquer natureza presentes nos líquidos intra e extracelular dos seres multicelulares, usada como força motriz, dessedenta e hidrata os seres vivos. Nas bacias hidrográficas alicerçam-se os diferentes ambientes, define os processos de produção da atividade econômica, o saneamento básico, dos ambientes urbanos e dos ambientes rurais, dos ecossistemas aquáticos e terrestres, todos movidos de acordo com os cursos d’água a ela pertencentes e atrelados ao ciclo hidrológico para a manutenção da vida dentro deste espaço. Neste contexto a saúde pública encontra-se intimamente ligada à água, na prevenção ou no isolamento das Doenças de Veiculação Hídrica (DVH), as Doenças Emergentes e Reemergentes (DER), para minimizar os agravos que a população possa vir a sofrer. Esse estudo buscou utilizar as notificações em saúde dos municípios pertinentes à bacia hidrográfica, por meio de levantamento histórico das DVH nos bancos de dados da saúde no âmbito estadual e federal de ocorrência na região em estudo. Os parâmetros de classificação dos principais cursos d’água foram obtidos pelo levantamento histórico do banco de dados estaduais, dos pontos de monitoramento, através dos resultados dos Indices de Qualidade da Água (IQA), do Índice de qualidade das águas brutas para abastecimento público (IAP), do Indice de qualidade das águas para a proteção da vida aquát... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Water is a component of all organisms vital processes, at the same time as it can carry microorganisms, dilute solutions of any nature present in the intra and extracellular fluids of the multicellular organisms, using as impellent, loss thirst and moisturizing. In the watersheds, it bases the different environmental, defines the processes of economic production, basic sanitation, urban and rural locations, aquatic and terrestrial ecosystems moved according to the watercourses that belong to it and the hydrological cycle for the maintenance of life. Public health is closely linked to water, preventing or isolating Waterborne Diseases (WD), emerging and reemerging diseases (ERD), minimizing the aggravations that the population will suffer. This study tries to use the notifications of occurrence in the region of the basin of Marinheiro Creeck, as parameters of quality classification of the water courses belonging to this region. The classification parameters of the main watercourses were obtained by the historical survey of the state database, the monitoring points, through the results of the Water Quality Index (IQA), the Raw Water Quality Index for public supply ( IAP) of the Water Quality Index for the protection of aquatic life (IVA). The performance of basic sanitation and water resources management minimizes the occurrence of social determinants through the infrastructure of sewage networks and storm water galleries, in the improvement and updating of water purification, ... (Complete abstract click electronic access below)
Mestre

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Water is essential to life and all living organisms and their supply is necessary for economic development and quality of life of human populations, but their quality has been altered by human actions. In semi-arid northeast, the water is an issue of concern, especially its quality. This region is common to the construction of reservoirs that capture rain water, streams and temporary rivers in search of ease this situation, being intended for various purposes. Water scarcity is a limiting factor for the economic and social development of the region and contributes to the maintenance of waterborne diseases. About 80% of diseases that occur in developing countries are infected by waterborne pathogens. Therefore, this study aimed to determine in two environments that are part of semil?nticos Armando Ribeiro Gon?alves reservoir, and a stretch of the river Assu, all located in the semiarid RN, the occurrence of opportunistic pathogenic bacteria; check the conceptions of teachers and health workers about the issues "waterborne diseases" and "bacteria" and a diagnosis of diarrheal diseases that affect the population in some municipalities of the semi-arid region of RN from a survey of epidemiological data. For identification of bacteria using commercial kits and the diagnosis of diarrheal disease was based on information from databases. The previous conceptions of teachers and health workers were obtained through questionnaires. The results confirmed the presence of opportunistic bacteria in the studied area, showing the importance of monitoring water quality. There was an under-reporting of cases of diarrhea pointing out flaws in the monitoring of Diarrheal Diseases and indicating the need to improve it. It was felt also the need to implement educational activities on topics dealt with both with teachers and health workers, since they were identified misconceptions on the subject
A ?gua ? essencial ? vida e a todos os organismos vivos e o seu suprimento ? necess?rio para o desenvolvimento econ?mico e para a qualidade de vida das popula??es humanas, mas sua qualidade vem sendo alterada pelas a??es antr?picas. No semi?rido nordestino, a ?gua ? uma quest?o preocupante, especialmente a sua qualidade. Nessa regi?o ? comum a constru??o de reservat?rios, que captam ?guas de chuvas, c?rregos e rios tempor?rios, na busca de amenizar essa situa??o, sendo destinados para diversas finalidades. A escassez de ?gua ? limitante para o desenvolvimento econ?mico e social da regi?o e contribui com a manuten??o das doen?as de veicula??o h?drica. Cerca de 80% das doen?as que ocorrem em pa?ses em desenvolvimento s?o veiculadas pela ?gua contaminada por microrganismos patog?nicos. Nesse contexto, este trabalho objetivou determinar, em dois ambientes semil?nticos que fazem parte do reservat?rio Armando Ribeiro Gon?alves, e em um trecho do rio Assu, todos localizados no semi-?rido potiguar, a ocorr?ncia de bact?rias patog?nicas oportunistas; verificar as concep??es de professores e agentes de sa?de a respeito dos temas doen?as de veicula??o h?drica e bact?rias , e realizar um diagn?stico das doen?as diarr?icas que acometem a popula??o de alguns munic?pios do semi-?rido do RN a partir do levantamento de dados epidemiol?gicos. Para identifica??o das bact?rias utilizaram-se kits comerciais, e o diagn?stico das doen?as diarr?icas foi realizado com base em informa??es de bancos de dados. As concep??es pr?vias de professores e agentes de sa?de foram obtidas por meio da aplica??o de question?rios. Os resultados confirmaram a presen?a de bact?rias oportunistas nos ambientes estudados, evidenciando a import?ncia de vigil?ncia da qualidade da ?gua. Verificou-se uma sub-notifica?ao de casos de diarr?ias apontando falhas no Monitoramento das Doen?as Diarr?icas, e indicando a necessidade de aprimor?-lo. Percebeu-se, ainda, a necessidade de implementa??o de atividades educativas sobre os temas abordados, tanto com os professores como com os agentes de sa?de, uma vez que foram identificadas concep??es equivocadas sobre o tema

Waterborne diseases continue to plague the poorest people in low-income countries and are estimated to cause 4,600,000 acute incidents of diarrhea resulting in over 2,000 deaths daily. A major challenge is performing microbiology tests to monitor drinking water quality. Friends of the Old (FOTO) implemented a novel strategy using evidence-based microbiology to educate communities about the relationship between contaminated water and disease. Two commercially available tests for E.coli, adapted for fieldwork, provided easily interpreted results of contamination that correlate with WHO's disease risk categories. Simple and effective household water treatment options 'solar pasteurization and/or chlorination' were provided to all 14,400 families and 42 schools in Lower Nyakach, Kenya. From February to May, 2015, adjacent districts had serious cholera outbreaks, but in Lower Nyakach, where education and the use of chlorine were nearly universal, there were no cases of cholera and steadily decreasing rates of diarrhea. A cross-sectional study was conducted to verify self-reported water treatment practices with evidence-based microbiological testing. A random sample of 377 households revealed that 95% treat their water each and every time they collect. Microbiological verification found 96% of household safe water storage vessels were low risk compared to their very high risk source water. A strong association (p < 0.001) existed between the observed decrease in diarrhea trends from health facilities in Lower Nyakach and exposure to the novel training. The strategy used by FOTO could be replicated to empower communities worldwide to identify contaminated drinking water sources and to reduce the incidence of waterborne disease.

Les eaux souterraines captées par les puits à grand diamètre dans la métropole de Cotonou (Sud du Bénin) sont tirées de l’aquifère du Quaternaire qui appartient au Bassin Sédimentaire Côtier. Cet aquifère côtier est particulièrement vulnérable non seulement de par son caractère superficiel et par l’influence des activités anthropiques mais aussi de par sa proximité avec les eaux salées du lac Nokoué et les mares contaminées. Les habitants des milieux défavorisés représentant environ 60% de la population de Cotonou sont les plus exposés face à l’utilisation quotidienne de cette ressource à des fins domestiques. Les campagnes de prélèvement spatio-temporel et les analyses physico-chimiques, isotopiques et bactériologiques, nous ont permis de décrire l’état actuel des eaux de l’aquifère peu profond, d’identifier les principaux facteurs et les périodes à risque de contamination des maladies hydriques notamment la leptospirose, une zoonose émergente méconnue à Cotonou. La nappe paraît principalement alimentée par les pluies locales. Mais l’utilisation conjointe des traceurs environnementaux (ions majeurs, ratio Cl/Br et isotopes stables), ont montré que cet aquifère peu profond est contaminé par les apports d'eau salée du lac Nokoué pendant la saison sèche, le lexiviat de déchets solides, d’eaux usées des fosses septiques et des fuites de latrines pendant la recharge par les pluies et aussi via les mares temporaires et permanentes. Même si l’interaction eau souterraine et les minéraux rocheux contribuent à la minéralisation, certains polluants anthropiques notamment les nitrates et les éléments traces (Mo, V, Zn et Al) peuvent parvenir à la nappe par lessivage ou être retenus par adsorption des sédiments sablo-argileux dans la Zone Non Saturée. D’autres comme le Fe et le Mn dépendent des conditions réductrices du milieu qui interviennent principalement au cours des processus de dénitrification et de dégradation de la matière organique. Les eaux contaminées de Cotonou se présentent donc comme un environnement favorable à la survie des leptospires en occurrence les mares obtenues après les précipitations du début de la saison des pluies. Le contact fréquent avec l'eau pendant la saison des pluies expose les habitants de Cotonou aux risques d'infections à la leptospirose. Les mesures de prévention des risques de contamination des maladies hydriques méritent sans doute une plus grande attention de la part des autorités sanitaires de la région côtière de l'Afrique de l'Ouest, en pleine expansion
Groundwater from large diameter wells in the Cotonou metropolis (southern Benin) is drawnfrom the Quaternary aquifer, which belongs to the Coastal Sedimentary Basin. This coastal aquifer is particularly vulnerable not only by its shallow nature and therefore risks from anthropogenic activities,but also by its proximity connectivity with a saline lake and contaminated pond waters. Inhabitants of underprivileged areas accounting for approximately 60% of the city's inhabitants are the most exposed to the daily use of this water resource for domestic purposes. Spatio-temporal sampling surveys andphysico-chemical, isotopic and bacteriological analyses helped to describe the current state of the shallow aquifer waters, to identify the main factors and periods at risk of contamination by waterborne diseases,in particular leptospirosis, an emerging zoonosis that is unknown in Cotonou. The aquifer appears to be mainly recharged by local rainfall. But the combined use of environmental tracers (major ions, Cl/Br ratio and stable isotopes), showed that this shallow aquifer is contaminated by salt water from Nokoué Lake during the dry season, by the leaching of solid waste, by wastewater from septic tanks and latrine leaks during rainfall recharge and via the recharge of temporary and permanent ponds. Although the interaction between groundwater and rock minerals contributes to mineralization, some anthropogenic pollutants such as nitrogen and trace elements (Mo, V, Zn and Al) can leach to groundwater or be retained by adsorption to sandy clay sediments in the unsaturated zone. Others, such as Fe and Mn, depend heavily on the redox conditions and the degradation of organic matter. The contaminated waters of Cotonou are a compatible environment for the survival of leptospirosis, especially in the pond waters that are formed at the start of the rainy season. Frequent contact with pond waters during the rainy season exposes the population of Cotonou to the risk of leptospirosis infections. Preventive measures against the risk of contamination of water-borne diseases undoubtedly deserve greater attention from the health authorities in the rapidly expanding populations in the coastal region of West Africa

Depleted water supplies, along with industrial and human waste, are driving a world water crisis that poses a growing risk to food markets, energy production, political stability, and human health (Global Water Security 2012). One obvious example of the this crisis is the more than 1 billion people who obtain their drinking water from contaminated sources (WHO/UNICEF 2006; Clasen et al. 2008). With a projected increase of 1.3 billion people between now and 2050, Africa will add more to the global population than any other world region (Haub and Kaneda 2013). For this research, visual learning design factors were incorporated into water literacy materials in order to study ways in which cultural and societal barriers can be overcome through culture- and gender-appropriate graphics designed to foster visual storytelling in the West African country of Niger. Women were targeted as the study population since they are the primary water fetchers and handlers in sub-Saharan Africa. Eye-tracking technology and GIS tools were used for quantification of the visual design characteristics. Research was conducted in 23 villages along the Niger River, and included 510 interviews, 693 focus group participants, 9 different cultural groups, over 30 hours of audio interviews, and 464 eye-tracking trials. Tobii X2-60 eye-tracking equipment was used in bush maternity wards, medicinal depositories, and mud-brick homes. Eye-tracking data were imported into an ArcGIS platform, where kernel density estimation (KDE) analyses were performed in an effort to compare and contrast the KDE of varying education levels, age groups, ethnic groups, and village types. Spatial autocorrelation analyses were used to evaluate whether the spatial pattern of attribute values (fixation time) was clustered, dispersed, or random. Results from this research suggest that visual communication can be used to overcome low education and cultural barriers for waterborne disease prevention. Using an adaptive visual-learning approach for the research method provided a creative alternative to conventional water-education materials, as most do not consider mother tongue and low literacy. Through visual communication, a novel way has been developed to understand how disadvantaged populations in sub-Saharan Africa visually process water literacy materials.

Background: Access to improved water and sanitation are key measures of the World Health Organizations. However, while a community can be classified as having access to improved water and sanitation, the possibility of microbiological contaminations exists. Globally, there is a need to assess the quality of drinking water to better classify levels of microbiological quality in attempts to reduce diarrheal disease burden. Utilizing the test for hydrogen sulfide (H2S) producing bacteria test is a cost effective and easy to use method that may be comparable to the traditional yet more costly method (IDEXX Colilert Quantitray). Due to a paucity of data on the test for H2S producing bacteria, this study was performed to examine how well the test for hydrogen sulfide (H2S) producing bacteria compared to traditional measure of fecal indicator bacteria total coliforms and E. coli in drinking water. Furthermore, an analysis of the ability of the test for H2S producing bacteria to predict diarrheal disease was also examined. Methods: The following conditions for the H2S were examined in the study: 2 volumes (10mL or 90mL), 2 incubation times (24 and 48 hours) and the use of a semi-quantitative scoring system that measured the intensity of the black precipitate formed (H2S). To examine how well these conditions compared to E. coli and total coliform results, the following analyses were performed: 1) analysis of sensitivity and specificity to examine presence/absence of bacteria in both samples, 2) linear regression to examine how well a semi-quantitative H2S scoring system predicted bacterial concentrations and 3) logistic regression to examine how well the H2S test predicted risk of diarrheal disease. Results: Within the dataset, there were 816 observations among the 7 communities involved in the study. The H2S test condition that had the highest sensitivity and specificity (94.23% and 36.07% respectively) for total coliforms was 90mL volume at 48 hours. This test condition also produced the highest sensitivity and specificity for E. coli (97.82% and 78.67%, respectively). An analysis using linear regression demonstrated that a semi-quantitative H2S scoring system was able to predict both total coliform and E. coli concentrations in the same samples. In a logistic regression analysis of diarrheal disease, the test of H2S producing bacteria suggested an increase in diarrheal disease risk for higher levels of H2S (OR of 1.18 (p=0.03; 1.02 – 1.35)). Discussion: The initial results here suggest that the use of the test for H2S producing bacteria has potential with high sensitivity (>90%) for E. coli and total coliforms. The application of the semi-quantitative scoring system may also have applications in predicting concentration of E. coli and total coliforms and well as possibly predicting diarrheal disease. However, more work needs to be completed to standardize the semi-quantitative approach to reduce subjectivity of scoring as well as examine the role of the test in additional epidemiologic studies. INDEX WORDS: waterborne disease, E. coli, Dominican Republic, microbial testing

This paper presents the findings of a study to assess patterns in local knowledge of and response to water quality and waterborne diseases in relation to seasonal changes in the Niger River Inland Delta. The study draws on field data collected in four villages along the Niger River in the Mopti district of Mali during September 2008. The major findings suggest: (1) water use behaviors and diarrheal disease management are influenced by the tremendous seasonal fluctuations in the riverine environment; (2) local awareness of the relationship between poor water quality, oral-fecal disease transmission, and waterborne disease is low; (3) interventions to mitigate the high incidence of childhood diarrhea and degraded water quality are limited by ongoing socio-economic, cultural, and institutional factors; and (4) womens level of health knowledge is socially and culturally dependent.

Water is a primary shared resource that connects all species across the landscape and can facilitate shared exposure to a community of waterborne pathogens. Despite remarkable global progress in sanitation and hygiene development in the past two decades, infectious diarrhea remains a prominent public health threat in sub-Saharan Africa. This thesis identifies and discusses persistent challenges limiting the success of current waterborne disease management strategies and several existing research hurdles that continue to impede characterization of microbial transmission and transport. In this work, the Chobe River watershed in Northern Botswana serves as a target study site for the application of hydrological modeling tools to quantify emergent water quality and health challenges in Southern Africa. A watershed model with extensive data requirements, the Hydrological Simulation Program – Fortran (HSPF), is used to identify primary data gaps and model assumptions that limit the progress of model development, and guide opportunities for data collection, tool development, and research direction. Environmental pathogen exposure risk and epidemiological outbreak dynamics are best described by interactions between the coupled human and environmental processes within a system. The challenge of reducing diarrheal disease incidence strengthens a call for research studies and management plans that join multiple disciplines and consider a range of spatiotemporal scales.
Master of Science

Orientador: Maria Jacira Silva Simões
Banca: José Paschoal Batistuti
Banca: Jonas Contiero
Resumo: A diarréia do viajante é o problema de saúde, mais comum, associado ao turista em termos de freqüência e impacto econômico contribuindo para a perda de rendimentos obtidos pelo turismo, em países em desenvolvimento. O objetivo da presente pesquisa foi identificar os agentes etiológicos mais freqüentes, nos surtos de doença transmitida por alimentos e/ou água em núcleos receptores turísticos, conhecer a sazonalidade e caracterizar a população segundo a idade e os alimentos suspeitos. Baseou-se nas notificações enviadas à Divisão de Doença de Transmissão Hídrica e Alimentar (DDTHA), Centro de Vigilância Epidemiológica (CVE), Secretaria Estadual de Saúde (SES) do Estado de São Paulo, no período 2002 a 2005 e informações das Vigilâncias Sanitárias da Direção Regional de Saúde (DIR). Os núcleos receptores turísticos selecionados foram: cidade de São Paulo e alguns municípios do interior como Águas de São Pedro, Campinas, Campos de Jordão, Franca, Jundiaí, Piracicaba, Pirassununga, Ribeirão Preto, São José dos Campos, São José do Rio Preto e do litoral como Guarujá, Peruíbe, Praia Grande, Santos e Ubatuba. Os resultados mostraram que o núcleo receptor turístico cidade de São Paulo, notificou 304 surtos, 3382 casos/doentes e dois óbitos. Do interior foram notificados 116 surtos e 8016 casos/doentes e três óbitos. Do litoral foram notificados 11 surtos, 253 casos/doentes e três óbitos, compreendendo um total de 431 surtos, sendo 129.340 comensais, 11.651 casos/doentes e 8 óbitos. Os agentes etiológicos mais freqüentes foram : vírus (58,08%), bactérias (72,72%), protozoários (4,67%), helmintos (0,83%), fungos (0,15%) e produtos químicos (0,12%). A freqüência dos agentes etiológicos foi: Rotavirus 31,86%; coliformes 28,38%; Salmonella sp. 13,55% (Salmonella Enteritidis 5,08% e Salmonella Typhimurium 2,88%)... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Travelers' diarrhea is the most common travel-related health problem in terms of frequency and economic impact. Travelers' diarrhea also contributes to loss of income from tourism in developing countries. The aim of the present study was to find the principle pathogens involved in outbreaks of food poisoning in tourist centers, and discover in what season the outbreaks occur, and age of the population. This study was based on informations sent to Divisão de Doença de Transmissão Hídrica e Alimentar (DDTHA), Centro de Vigilância Epidemiológica (CVE), Secretaria Estadual de Saúde (SES) do Estado de São Paulo and Vigilâncias Sanitárias da Direção Regional de Saúde (DIR) from 2002 - 2005. The tourist centers selected for the study were: São Paulo city; Águas de São Pedro, Campinas, Campos de Jordão, Franca, Jundiaí, Piracicaba, Pirassununga, Ribeirão Preto, São José dos Campos, São José do Rio Preto; Guarujá, Peruíbe, Praia Grande, Santos, and Ubatuba. The results showed that São Paulo city reported 304 outbreaks, 3,382 cases/disease and two deaths. From the interior of the state of São Paulo (116 outbreaks), 8016 cases/disease and 3 deaths were registered. From the coast (11 outbreaks), 253 cases/disease and 3 deaths were registered. In total there were 431 outbreaks, 129,340 persons exposed, 11,651 cases/disease and 8 deaths. The etiological agents were bacteria (72.72%), virus (58.08%), protozoa (4.67%), nematodes (0.83%), fungi (0.15%) and chemical products (0.12%). The frequency of causative pathogens was: Rotavirus 31.86%, coliforms 28.38%... (Complete abstract click electronic access below)
Mestre

Thesis (M.S.)--Worcester Polytechnic Institute.
Keywords: cell culture; PCR; coliphage; coliform; fecal indicator; enteric virus; waterborne disease outbreak; TTV; torque teno virus. Includes bibliographical references (leaves 96-117).

Pathogen contamination, typically quantified by elevated levels of fecal indicator bacteria (FIB), remains the leading cause of surface water-quality impairments in the United States. Continuous watershed-scale models are typically employed to facilitate Total Maximum Daily Load (TMDL) restoration efforts. Due to limited understanding of microbial fate and transport, predictions of FIB concentrations are associated with considerable uncertainty relative to other water-quality contaminants. By focusing on a data-rich instrumented urban watershed, this study aims to improve understanding of microbial fate and transport processes. Weekly FIB concentrations in both the water column and streambed sediments were monitored for one year, and statistical correlations with hydrometeorological and physicochemical variables were identified. An intensive six storm intra-sampling campaign quantified and contrasted loading trends of both traditional regulatory FIB and emerging Microbial Source Tracking (MST) markers. Together, these intensive monitoring efforts facilitated evaluation of the impacts of bacteria-sediment interactions on the predictions of daily FIB concentrations in Hydrological Simulation Program-Fortran (HSPF) over multiple years. While superior overall model performance was demonstrated as compared to earlier efforts, the inclusion of bacteria-sediment interactions did not improve performance. Large wet-weather microbial loading appears to have dwarfed the effects of FIB release and resuspension from sediment. Although wet-weather loading is generally considered as a primary source of waterbody microbial loads, dry-weather periods are more directly associated with public health concern, which may be a more suitable area for future model-refinement efforts. Site evaluation is critical to determine whether the added model complexity and effort associated with partitioning phases of FIB can be sufficiently offset by gains in predictive capacity. Finally, a stochastic framework to translate simulated daily FIB concentrations into estimates of human illness risks is presented that can be can be readily integrated into existing TMDLs. As even small concentrations of FIB from human sources are associated with great risk, and monitoring efforts indicated moderate/high levels of human-associated MST marker in this watershed, remediation efforts to protect public health would be best directed toward infrastructure improvements. Uncertainty analysis indicates more site-specific knowledge of pathogen presence and densities would best improve the estimation of illness risks.
Ph. D.

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Universidade Estadual Paulista (UNESP)
A diarréia do viajante é o problema de saúde, mais comum, associado ao turista em termos de freqüência e impacto econômico contribuindo para a perda de rendimentos obtidos pelo turismo, em países em desenvolvimento. O objetivo da presente pesquisa foi identificar os agentes etiológicos mais freqüentes, nos surtos de doença transmitida por alimentos e/ou água em núcleos receptores turísticos, conhecer a sazonalidade e caracterizar a população segundo a idade e os alimentos suspeitos. Baseou-se nas notificações enviadas à Divisão de Doença de Transmissão Hídrica e Alimentar (DDTHA), Centro de Vigilância Epidemiológica (CVE), Secretaria Estadual de Saúde (SES) do Estado de São Paulo, no período 2002 a 2005 e informações das Vigilâncias Sanitárias da Direção Regional de Saúde (DIR). Os núcleos receptores turísticos selecionados foram: cidade de São Paulo e alguns municípios do interior como Águas de São Pedro, Campinas, Campos de Jordão, Franca, Jundiaí, Piracicaba, Pirassununga, Ribeirão Preto, São José dos Campos, São José do Rio Preto e do litoral como Guarujá, Peruíbe, Praia Grande, Santos e Ubatuba. Os resultados mostraram que o núcleo receptor turístico cidade de São Paulo, notificou 304 surtos, 3382 casos/doentes e dois óbitos. Do interior foram notificados 116 surtos e 8016 casos/doentes e três óbitos. Do litoral foram notificados 11 surtos, 253 casos/doentes e três óbitos, compreendendo um total de 431 surtos, sendo 129.340 comensais, 11.651 casos/doentes e 8 óbitos. Os agentes etiológicos mais freqüentes foram : vírus (58,08%), bactérias (72,72%), protozoários (4,67%), helmintos (0,83%), fungos (0,15%) e produtos químicos (0,12%). A freqüência dos agentes etiológicos foi: Rotavirus 31,86%; coliformes 28,38%; Salmonella sp. 13,55% (Salmonella Enteritidis 5,08% e Salmonella Typhimurium 2,88%)...
Travelers' diarrhea is the most common travel-related health problem in terms of frequency and economic impact. Travelers' diarrhea also contributes to loss of income from tourism in developing countries. The aim of the present study was to find the principle pathogens involved in outbreaks of food poisoning in tourist centers, and discover in what season the outbreaks occur, and age of the population. This study was based on informations sent to Divisão de Doença de Transmissão Hídrica e Alimentar (DDTHA), Centro de Vigilância Epidemiológica (CVE), Secretaria Estadual de Saúde (SES) do Estado de São Paulo and Vigilâncias Sanitárias da Direção Regional de Saúde (DIR) from 2002 - 2005. The tourist centers selected for the study were: São Paulo city; Águas de São Pedro, Campinas, Campos de Jordão, Franca, Jundiaí, Piracicaba, Pirassununga, Ribeirão Preto, São José dos Campos, São José do Rio Preto; Guarujá, Peruíbe, Praia Grande, Santos, and Ubatuba. The results showed that São Paulo city reported 304 outbreaks, 3,382 cases/disease and two deaths. From the interior of the state of São Paulo (116 outbreaks), 8016 cases/disease and 3 deaths were registered. From the coast (11 outbreaks), 253 cases/disease and 3 deaths were registered. In total there were 431 outbreaks, 129,340 persons exposed, 11,651 cases/disease and 8 deaths. The etiological agents were bacteria (72.72%), virus (58.08%), protozoa (4.67%), nematodes (0.83%), fungi (0.15%) and chemical products (0.12%). The frequency of causative pathogens was: Rotavirus 31.86%, coliforms 28.38%... (Complete abstract click electronic access below)

A toxoplasmose é uma zoonose de distribuição mundial, altamente prevalente na população humana e animal. A doença é geralmente benigna e autolimitada, mas pode ocasionar déficits visuais graves em cerca de 2 a 3% dos indivíduos acometidos, e ainda, assumir formas graves e letais em pacientes imunossuprimidos e em fetos de gestantes com infecção aguda. As principais formas de transmissão da doença são o consumo de água e alimentos crus contaminados com oocistos e a ingestão de carne crua ou mal cozida contendo cistos teciduais do Toxoplasma gondii. Na literatura há relatos de vários surtos epidêmicos de toxoplasmose humana, porém a análise descritiva destes surtos é pontual e restrita, com informações isoladas em relação período de incubação e gravidade dos sintomas que poderiam estar relacionados à forma infectante do agente. No presente trabalho analisamos a influência da forma infectante do T. gondii no quadro da doença aguda humana, através de revisão sistemática das principais bases de dados bibliográficos na área de Saúde Pública (Cochrane, Embase, Food Sciences & Tech Abstracts, Lilacs, PubMed, Scopus e Web of Science), além de publicações em boletins epidemiológicos (Boletim Epidemiológico Paulista, Boletim Eletrônico Epidemiológico SVS) e anais de congressos nacionais e internacionais de áreas correlatas. As pesquisas nas bases de dados bibliográficos foram realizadas utilizando idiomas em português e inglês para os termos: surtos de toxoplasmose humana (human toxoplasmosis outbreak). Os critérios de inclusão dos estudos levaram em consideração artigos e resumos que relatassem surtos epidêmicos de toxoplasmose humana com descrição da forma infectante do agente e quadro clínico da doença. Na busca eletrônica inicial, foram obtidos 431 artigos referentes a surtos mundiais e nacionais de toxoplasmose humana, provenientes de diferentes formas de transmissão da doença, porém foram elegíveis para o trabalho somente 33 artigos, incluindo um surto ocorrido recentemente na região de Araraquara, Estado de São Paulo, cuja investigação epidemiológica foi conduzida por nossa equipe. A análise da revisão sistemática sugere que o número de casos confirmados nos surtos é maior quando a transmissão ocorre por oocistos, sendo o solo e a água associados a esta forma de transmissão. Quanto aos achados clínicos, a infecção por cistos parece induzir um período de incubação menor do que o observado para oocistos. Não houve relação da forma infectante com o sexo predominante e faixa etária nas populações amostrais. Os surtos foram descritos mais frequentemente nas Américas que em outros continentes. Estes dados sugerem que a forma infectante do T.gondii interfere no quadro da toxoplasmose aguda.
Toxoplasmosis is a zoonosis of worldwide distribution, highly prevalent in the human and animal population. The disease is usually benign and self-limiting but can cause severe visual deficits in about 2 to 3% of affected individuals, and also take serious and lethal in immunosuppressed patients and in fetuses of pregnant women with acute infection. The most important modes of transmission are consumption of water and uncooked food contaminated with oocysts and the ingestion of raw or undercooked meat containing tissue cysts of Toxoplasma gondii. In literature there are reports of several human toxoplasmosis outbreaks, but the descriptive analysis of these outbreaks is punctual and restricted, with isolated information regarding the incubation period and severity of symptoms that could be related to the infective form of the agent. In this study we analyze the influence of infective form of T. gondii in the context of acute human disease, through a systematic review of the major bibliographic databases in the area of Public Health (Cochrane, Embase, Food Sciences & Tech Abstracts, Lilacs, PubMed, Scopus e Web of Science), as well as publications in epidemiological bulletins (Boletim Epidemiológico Paulista, Boletim Eletrônico Epidemiológico SVS) and annals of national and international conferences in related areas. This research on bibliographic databases was performed using English and Portuguese languages for the terms: human toxoplasmosis outbreak (surtos de toxoplasmose humana). The inclusion criteria of the studies took into consideration articles and abstracts that reported outbreaks of human toxoplasmosis with description of the infective form of the agent and the clinical disease. In the initial electronic search, 431 articles were obtained regarding global and national outbreaks of human toxoplasmosis from different main forms of disease transmission, but were eligible to work only 33 articles, including a recent outbreak in the region of Araraquara State of São Paulo, which epidemiological investigation was conducted by our team. The analysis of systematic review suggests that the number of confirmed cases in outbreaks is greater when the transmission occurs by oocysts, and the soil and water are associated with this form of transmission. Regarding clinical findings, cysts infection seems to induce an incubation period less than that observed for oocysts. No relationship between the infective form with the predominant sex and age group in the sample populations. Outbreaks were reported more frequently in the Americas than in other continents. These data suggest that the infective form of T. gondii interferes in the context of acute toxoplasmosis.

Les épidémies de gastro-entérite aigüe liées à l’eau du robinet demeurent un enjeu de santé publique au 21ème siècle dans les pays développés. La majorité des dispositifs de surveillance mis en place dans les pays se caractérisent par une sous-déclaration. En France, l’amélioration de la surveillance de ces évènements repose sur l’exploitation des données de l’Assurance Maladie. L’objectif de notre travail est de proposer une méthode pour améliorer la sensibilité et la spécificité de la détection des épidémies de gastro-entérite aigüe d’origine hydrique. Trois études ont été menées pour i) évaluer la capacité des données de l’Assurance Maladie à décrire des épidémies de gastro-entérite aigüe d’origine hydrique, ii) adapter une méthode de détection spatio-temporelle en intégrant l’exposition à l’eau du robinet, iii) évaluer les performances de cette méthode. Notre travail a permis de développer une méthode de détection spatio-temporelle des épidémies hydriques en tenant compte des unités géographiques de distribution d’eau avec une bonne sensibilité et une bonne valeur prédictive positive. Les performances de détection sont principalement liées à la taille de l’épidémie. La capacité des données de l’Assurance Maladie à détecter des épidémies d’origine hydrique peut être influencée par les habitudes de recours aux soins, la sensibilisation de la population au risque infectieux d’origine hydrique et le niveau d’agrégation temporel des cas de gastro-entérite aigüe. La finalité de nos travaux de recherche est l’application opérationnelle pour la détection automatisée des épidémies hydriques dans une finalité de prévention et de réduction de leur impact sanitaire
Waterborne disease outbreaks (WBDO) of acute gastrointestinal illness remain a public health concern in the 21st century in developed countries. Almost all surveillance systems implemented in countries are characterized by underreporting. In France, the improvement of monitoring these events is based on the use of data from the French Health Insurance. The aim of our work was to propose a method to improve the sensitivity and specificity of the detection of WBDO. Three studies were conducted to i) evaluate the ability of French Health Insurance data to describe WBDO ii) apply a method of space-time detection by integrating the exposure to tap water, iii) evaluate the performance of this method. Our work allowed developing a method of space-time detection of WBDO by taking into account geographical units for drinking water networks units with a good sensitivity and positive predictive value. The performances for detection are mainly related to the size of the epidemic. The ability of the data from the French Health Insurance to detect WBDO can be influenced by the health-seeking behavior of people, awareness of the population to the risk of WBDO and the temporal aggregation level of cases of acute gastrointestinal illness. The purpose of our research is to carry out an operational design for the automated detection of WBDO in a purpose of prevention and reduction of health impact

Submitted in fulfilment of the requirements for the Master of Technology Degree: Environmental Health, Durban University of Technology, 2012.
Waterborne diseases represent substantial global burden of disease and children under the age of five are more susceptible to these diseases compared to adults. The aim of this study was to determine the microbiological quality of Nyabarongo River water used for domestic purposes, women’s knowledge, attitudes and practices (KAP) on water usage and waterborne diseases and its link to the diarrhoea outbreaks experienced in two rural communities: Rusheshe and Ayabaraya of Masaka in Rwanda. A total of 35water samples were collected from Nyabarongo River and from study households which used slow sand filtration (SSF) or Sûr’Eau as treatment methods and analyzed for total coliform and faecal coliform indicators. For household samples turbidity was also analyzed. Retrospective records from Masaka Health Centre were reviewed to determine the prevalence of waterborne diseases from the study areas during 2010. Further, a structured questionnaire was administered to 324 women residents of the study areas to elicit information on their KAP on water handling and waterborne diseases. SPSS Predictive Analytic Software (PASW) Statistics version 18.0 (IBM, Somers, NY) and STATA Release (Version 11.0, College Station, Texas USA) were used for data analysis. Results showed that the mean values of total and faecal coliforms of river and household water samples were above the WHO and Rwandan recommended guidelines. The mean values of total coliform and faecal coliform were significantly lower (p ≤ 0.05) in both filtered and Sûr’Eau treated water than in river water. No statistical differences of means were observed for both total coliform and faecal coliform counts between samples taken from filtered and Sûr’Eau treated water containers (p=0.80 (TC) and p = 0.56 (FC). However, turbidity values were significantly lower in filtered water using SSF than in Sûr’Eau treated water samples (p =0.002). Out of 2814 records form Masaka Health Centre during 2010, 160 cases were identified as having diarrhoeal diseases. Furthermore, respondents who used Nyabarongo River as source of water were more likely to have symptoms of diarrhoea (OR =5.35; CI: 2.12 - 14.46; p <0.05). The frequency of diarrhoea were significantly higher among people who did not wash hands before food preparation (p = 002) and after using a toilet (p = 0.007) than among those who did. There was a statistically significant association of level of education levels and drinking water treatment practices at the household level (p < 0.05). Respondents with primary school education only and those with high school education were more likely to wash their hands after using a toilet (OR= 5.24, CI 1.42-19.38, p =0.01 and OR = 7.15, CI = 1.79 -28.62, p=0.01, respectively) than those who did not attend school. No significant associations were identified between educational levels and washing hands before food preparation. The findings of this study points to the facts that water sourced from Nyabarongo River is unsafe for human consumption even after prescribed treatment, such as the use of SSF and Sûr’Eau, and could increase the prevalence of waterborne diseases and therefore calls for urgent provision of potable water. Women in the study areas had limited knowledge regarding water storage practices for prevention of household water contamination and this; underscore the need for more water handling practices and hygiene education in rural communities.

Phytophthora pini Leonian, recently re-established from P. citricola I, is a pathogen with a wide range of forest and nursery hosts. It causes foliar infections in horticultural nurseries in Oregon, where recirculating irrigation systems are common. Increased use of recirculating irrigation systems may contribute to disease caused by waterborne plant pathogens. Simulated nursery chamber experiments were utilized to investigate the relationship between Phytophthora pini zoospore inoculum dose and disease on Rhododendron. Disease incidence in this system was unexpectedly low despite high inoculum levels tested, so further experiments under lab conditions were conducted to explore possible causes. Detached leaf assays were conducted to determine how inoculum dose, leaf wounding, and agitation of zoospore inoculum affected foliar infection of Rhododendron. Wounded and nonwounded leaves were dipped into suspensions of zoospores that were either untreated, mechanically agitated by vortexing to cause encystment, or pumped through an irrigation sprayer system. Disease severity (lesion area) and incidence (number of lesions per leaf area) were measured over seven days. At inoculum levels of ���10,000 propagules/mL, motile zoospores infected both wounded and nonwounded leaves. Vortexing or pumping resulted in zoospore encystment, and inoculation with these treatments caused disease almost exclusively on wounded leaves. No disease symptoms were observed following inoculation with any inocula at ��� 2,000 propagules/mL. Scanning electron microscopy of leaves inoculated with encysted propagules showed germinated cysts with hyphae growing over and around stomata without entering leaf tissue until reaching a wound site. Nonwounded leaves inoculated with motile spores showed stomata penetrated by hyphae. These findings indicate the importance of zoospore motility in reaching suitable infection sites, and demonstrate the impact of zoospore encystment on disease development. This has implications for disease management in nurseries where pruning wounds are common and the pumping of infested irrigation water may influence zoospore motility and infectivity.
Graduation date: 2013

Toxoplasma gondii and Cyclospora cayetanensis are protozoa, of worldwide distribution, capable of infecting humans. Transmission of these protozoa generally occurs via the oral-fecal route, with foods consumed raw and contaminated water , consensually assumed as sources of contamination. The aim of this study was the detection and characterization of Toxoplasma gondii and Cyclospora cayetanensis in fresh vegetables and water in order to assess the possible risk to consumer food safety. Twenty-five samples were collected from an agriculture exploration, more specifically, 13 samples of water and 12 samples of vegetables. The potential oocysts of Toxoplasma gondii and Cyclospora cayetanensis were concentrated by applying high resolution water filtration and immunomagnetic separation (Method 1623.1, EPA, 2012) in order to remove oocysts of Cryptosporidium spp. and cysts of Giardia spp. and recover the parasites of interest: Toxoplasma gondii and Cyclospora cayetanensis. The detection of Toxoplasma gondii and Cyclospora cayetanensis was performed by conventional PCR, using specific primers for a 183 bp sequence of the 529 bp repetitive region of T. gondii; and for a 116 bp sequence of the ITS2 region and a 298 bp sequence for 18S rRNA gene of C. cayetanensis. All PCR-positive DNA samples were purified and sequenced. In addition, the presence of the parasite was observed by fluorescence microscopy, taking advantage of the autofluorescence of the oocysts under ultraviolet light, as well as staining techniques. None of the samples showed to be contaminated with T. gondii, however, 28% of the samples showed positive results for C. cayetanensis when the PCR technique was performed. These fragments were confirmed by sequencing. Moreover, microscopic autofluorescence and staining techniques supported the presence of structures compatible with C. cayetanensis oocysts. The results obtained provide relevant evidence of contamination of fresh vegetables and water with C. cayetanensis oocysts.
Toxoplasma gondii e Cyclospora cayetanensis são protozoários, de distribuição mundial, com capacidade de infetarem o Homem. A transmissão destes protozoários ocorre, geralmente, por via oral-fecal, sendo os alimentos de origem vegetal consumidos crus e a água contaminada, assumidos, consensualmente, como fontes de contágio. O objetivo deste estudo foi a deteção e caracterização de Toxoplasma gondii e Cyclospora cayetanensis em vegetais e água, com o intuito de avaliar o possível risco para a segurança alimentar do consumidor. Foram recolhidas 25 amostras de uma exploração agrícola, mais especificamente, 13 amostras de água e 12 amostras de vegetais. Os potenciais oocistos de Toxoplasma gondii e Cyclospora cayetanensis foram concentrados através da filtração de água de alta resolução e por separação imunomagnética (Método 1623.1, EPA, 2012), com o intuito de remover oocistos de Cryptosporidium spp. e cistos de Giardia spp. e recuperar os parasitas de interesse: Toxoplasma gondii e Cyclospora cayetanensis. A deteção de Toxoplasma gondii e de Cyclospora cayetanensis foi realizada através de PCR convencional, utilizando primers específicos para uma sequência de 183 pb da região repetitiva de 529 pb de T. gondii; e para uma sequência de 116 pb da região ITS2 e uma sequência de 298 pb do gene 18S rRNA de C. cayetanensis. Todas as amostras de ADN positivas para PCR foram purificadas e sequenciadas. Além disso, a presença do parasita foi observada por microscopia de fluorescência, aproveitando a autofluorescência dos oocistos sob luz ultravioleta, assim como também foram utilizadas técnicas de coloração. Nenhuma das amostras mostrou estar contaminada com T. gondii, no entanto, 28% das amostras apresentaram resultados positivos para C. cayetanensis quando realizada a técnica de PCR. Esses fragmentos foram confirmados por sequenciação. Além disso, a microscopia de fluorescência e técnicas de coloração confirmaram a presença de estruturas compatíveis com oocistos de C. cayetanensis. Os resultados obtidos fornecem evidências relevantes de contaminação de vegetais frescos e água com oocistos de C. cayetanensis.
Mestrado em Microbiologia

Tese de mestrado, Engenharia Farmacêutica, Universidade de Lisboa, Faculdade de Farmácia, 2017
Infectious Diseases, in particular food- and waterborne diseases (FWD), are critical public health concerns nowadays, reinforcing that public health laboratories should establish accurate strategies that allow a proper epidemiological surveillance of the causative infectious agents. With the advances in the whole genome sequencing (WGS) technologies, and associated bioinformatics, genome-based typing tools are becoming the gold standard methodology for laboratory epidemiological monitoring of FWD, with recognized benefits for public health. In the present study, we aimed at starting the implementation of WGS/bioinformatics techniques (in place of traditional typing methods) for routine epidemiological surveillance of FWD-associated pathogens, more specifically of four of the most clinically relevant bacterial pathogens: Listeria monocytogenes, Salmonella enterica, verocytotoxin-producing Escherichia coli (VTEC) and Campylobacter jejuni. The WGS of multiple bacterial isolates (n= 89) firstly allowed us to apply and test multiple bioinformatics tools for in silico capture of the typing data routinely provided by the traditional pheno- and genotyping techniques. In general, high levels of concordance were reached, opening good perspectives that backwards compatibility with “historical” typing data may be ensured during this technology transfer process. Subsequently, in order to test novel genome-based typing tools for routine surveillance of FWD, we implemented and assayed core genome multilocus sequence typing (cgMLST) schemes and core-genome SNP-based strategies, with unequivocal gains regarding the discriminatory power. Moreover, the results were particularly concordantly between the two strategies, which also stood when applying either “assembly-free” or “de novo assembly-based” core-genome SNP-based strategies. Finally, our insights on the potential of WGS/bioinformatics to predict bacterial virulence and antimicrobial susceptibility profiles provided very optimistic perspectives for the future routine application of WGS for such purposes. In conclusion, the present study constitutes an unequivocally important step towards the application of genome-based typing tools as the future gold standard technique for routine epidemiological surveillance of FWD in Portugal.
As doenças infecciosas, em particular as doenças transmitidas por alimentos e água, são importantes problemas de Saúde Pública, apresentando taxas relevantes de morbilidade e mortalidade na população em geral. Neste contexto, e tendo também em conta o preocupante aumento do número de casos de resistência a agentes antimicrobianos, os laboratórios de Microbiologia clínica e Saúde Pública, nomeadamente os Laboratórios Nacionais de Referência, procuram continuamente implementar e validar estratégias que assegurem uma eficiente vigilância epidemiológica dos agentes infeciosos causadores dessas doenças. Em particular, é importante estabelecer metodologias que permitam, não só uma detecção inequívoca desses agentes patogénicos, mas também técnicas de “tipagem” que permitam a sua posterior discriminação e classificação. Com os tremendos avanços nas tecnologias de sequenciação total do genoma, e ferramentas bioinformáticas associadas, é esperado que técnicas de tipagem baseadas na análise dos genomas microbianos em larga escala se tornem as técnicas-padrão para vigilância laboratorial de doenças transmitidas por alimentos e água num futuro muito próximo. Espera-se que esta transição tecnológica traga benefícios inequívocos para a Saúde Pública, tais como: i) o aumento da capacidade de resolução na caracterização genotípica de agentes patogénicos, ampliando, por exemplo, a capacidade para detectar e investigar surtos e fontes de infecção; ii) uma melhor identificação e monitorização da emergência de agentes que possam constituir novas ameaças para a Saúde Pública (tais como estirpes multiresistentes) facilitando a resposta a situações de emergência; e, iii) uma maior capacidade para prever o potencial patogénico das estirpes, nomeadamente o seu perfil de resistências a agentes antimicrobianos ou outros fenótipos de virulência, podendo estes dados facilitar as tomadas de decisão clínica e terapêutica. Neste sentido, este estudo, desenvolvido no Instituto Nacional de Saúde Doutor Ricardo Jorge, teve como principal objectivo começar a implementar técnicas de tipagem baseadas na sequenciação total do genoma/bioinformática (em substituição das técnicas tradicionais de tipagem) para vigilância epidemiológica de agentes patogénicos associados a doenças transmitidas pelos alimentos e água, especificamente quatro agentes bacterianos com importante impacto na Saúde Pública: Listeria monocytogenes, Salmonella enterica, Escherichia coli produtora de verotoxinas (VTEC) e Campylobacter jejuni. Através da sequenciação total do genoma de múltiplos isolados bacterianos (n=89), procurou-se em primeiro lugar testar ferramentas bioinformáticas para extracção/captura in silico de dados de tipagem fornecidos pelas técnicas tradicionais de “genotipagem“ (por exemplo, as “sequência-tipo” obtidas pela técnica de Multilocus sequence typing – MLST) e “fenotipagem” (por exemplo, o serótipo). Em geral, os resultados mostraram altos níveis de concordância, deixando, assim, boas perspectivas de que os dados históricos de tipagem poderão continuar a ser usados para melhor caracterização dos agentes patogénicos durante e após o processo de transição tecnológica. Esta valência conferida pela nova abordagem de tipagem baseada na análise dos genomas bacterianos é bastante relevante pois existe um grande conhecimento científico sobre a distribuição geográfica de estirpes apresentando certos perfis genotípicos e fenotípicos, bem como sobre a sua associação com determinadas fontes de infeção e/ou manifestações clinicas. De seguida, com o objectivo de testar novas estratégias de tipagem à escala do genoma bacteriano para vigilância laboratorial de doenças transmitidas por alimentos e água, foram implementadas e avaliadas, para os quatro agentes patogénicos do Homem em estudo, as seguintes abordagens bioinformáticas: core genome multilocus sequence typing (cgMLST) e core-genome Single Nucleotide Polymorphisms (coreSNP). Os resultados obtidos pelas duas estratégias foram particularmente concordantes, tendo claramente aumentado o poder de resolução em relação às técnicas tradicionalmente aplicadas para discriminação e classificação de estirpes daqueles agentes bacterianos. Além disso, foi também notória a concordância entre duas técnicas de coreSNP testadas: uma baseada no mapeamento bioinformático contra sequências conhecidas e outra baseada na montagem de novo da sequência do genoma dos isolados bacterianos. No caso desta última abordagem, o uso de diferentes software para montagem dos genomas de novo não teve impacto nas inferências filogenéticas construídas com base na diversidade genética do core-genoma. Ainda no âmbito da implementação de novas estratégias de tipagem assentes na análise bioinformática dos genomas bacterianos, destaca-se o facto de o esquema de cgMLST aplicado para discriminação de isolados clínicos de L. monocytogenes ter grande potencial para vir a ser implementado e validado à escala mundial para vigilância epidemiológica deste importante agente patogénico humano. Neste estudo, os resultados gerados com esta nova abordagem (os quais foram corroborados pelas estratégias in house de coreSNP) permitiram já sinalizar clusters de isolados geneticamente muito próximos, os quais vão ser alvo de investigação epidemiológica retrospectiva. Destaca-se, ainda, o facto da flexibilidade conferida pelas estratégias de coreSNP (i.e., a amplitude do genoma analisado é dependente do conjunto de estirpes sob avaliação, com impacto no poder de discriminação) ter permitido, por exemplo, confirmar a identidade genética entre dois isolados clínicos de L. monocytogenes colhidos do mesmo paciente (de diferentes sítios anatómicos) e reforçar dados provenientes de métodos de tipagem tradicionais sugerindo que três estirpes de S. enterica terão estado associadas a um surto. Neste estudo foram também aplicadas ferramentas bioinformáticas para previsão da presencia/ausência de genes associados à virulência ou à resistência a antibióticos. Este primeiro passo no uso da técnica de sequenciação total do genoma/bioinformática para previsão rápida do arsenal de factores de virulência, bem como de perfis de resistência a agentes antimicrobianos deixa perspectivas muito optimistas para a futura aplicação por rotina destas novas abordagens com vista à previsão do potencial patogénico daqueles agentes infeciosos. De facto, foi possível determinar in silico o reportório de genes potencialmente mediadores de virulência apresentado por estirpes de E. coli, nomeadamente os genes que codificam a bem conhecida Shiga toxina. Por outro lado, foi já possível confirmar certas associações genótipo-fenótipo no que respeita aos perfis de resistência a antibióticos apresentados por isolados de S. enterica e C. jejuni. Adicionalmente, para melhor exposição dos resultados, tirou-se ainda partido de novas plataformas focadas em permitir uma melhor visualização e interpretação de dados de tipagem, as quais têm sofrido um forte desenvolvimento fruto do paralelo crescimento dos campos da genómica microbiana e da bioinformática. A sua aplicação neste estudo permite perspetivar que estas ferramentas serão de grande utilidade para o futuro estabelecimento, de forma dinâmica e intuitiva, de correlações entre os perfis genéticos de certas estirpes e os dados clínicos/epidemiológicos a elas associadas. Por fim, é de ressalvar que a futura avaliação de todas as ferramentas bioinformáticas (e variáveis inerentes) aqui testadas a uma maior escala (envolvendo um grande número de isolados bacterianos) no decurso da processo de transição tecnológica irá certamente reforçar as nossas expectativas quanto à sua aplicabilidade e utilidade no contexto da vigilância de doenças infecciosas. Em conclusão, o presente estudo constitui um passo inequivocamente importante para o estabelecimento de ferramentas de tipagem baseadas na sequenciação total do genoma (e análises bioinformáticas associadas) como técnicas-padrão a usar num futuro próximo para a vigilância epidemiológica de doenças infecciosas transmitidas por alimentos e água em Portugal. Por outro lado, os dados gerados com este trabalho permitiram já lançar importantes hipóteses científicas que estão actualmente a ser alvo de novos estudos, incluindo estudos focados em confirmar potenciais relações epidemiológicas aqui sugeridas, bem como estudos de investigação focados em estabelecer relações genótipo-fenótipo.
The experimental work was performed in the Bioinformatics Unit of the Department of Infectious Diseases of the National Institute of Health Dr. Ricardo Jorge (INSA). All the facilities, equipments, materials and support were gently provided by INSA.

Climate change is expected to cause changes in precipitation and runoff patterns, likely increasing the risk of waterborne infectious disease in some areas. In this context, the research objectives were to describe links between weather, water quality, and infectious gastrointestinal illnesses (IGI) in Nunatsiavut, Canada, which necessarily involved evaluating the quality and usefulness of data captured by the local health registry system. For this evaluation, IGI was used as a reference syndrome. Community-based meteorological stations captured weather data; trained local personnel conducted water quality testing. Clinic records provided IGI-related data (2005-2008). This study is the first to systematically gather and describe baseline empirical data on weather, water quality, and health in Nunatsiavut. It showed the necessity of improving Inuit health data quality and monitoring environmental health variables consistently and systematically across all Arctic regions. These data are critical to inform adaptation strategies for managing impacts of climate change on health.

The risk of waterborne infections acquired from the consumption of contaminated water is related to changes in source water fecal contamination, which is often influenced by land-use and hydro-meteorological conditions in the surrounding watershed. The impact of land-use composition on surface water contamination was explored in order to determine the risk of surface water contamination associated with land-use change. Highest contamination was observed in watersheds characterized by more than 12.5% agricultural and more than 1.6% urban land (mean fecal coliform (FC) concentration of these 5 sites = 135 CFU 100ml-1 while the British Columbia (BC) raw water quality guideline = 100 CFU 100ml-1). Contamination increased exponentially, and violated BC raw water quality guidelines with greater frequency, in relation to greater agricultural land in the upstream watershed. Additional factors, such as sewage treatment plants, low dilution in smaller streams, and higher temperatures were also associated with greater contamination. These results indicate the high level of risk posed by agricultural and urban development and the need for source water protection. Fecal contamination levels in source water are also influenced by rainfall and snowmelt-induced surface runoff that transport diffuse fecal contaminants into surface water. Seasonal levels of fecal contamination in surface water was related to the watershed hydro-climatic regime for around half of the watersheds examined. Watersheds with snowmelt-dominant (SD) runoff regimes showed stronger evidence of hydro-meteorological variability driving seasonal contamination levels than those with rainfall and snowmelt-influenced (RSI) and rainfall-dominant (RD) runoff regimes, and thus are more prone to experiencing changes to seasonal variability resulting from climate change. Projected increases in mean annual temperatures of between 1.70C and 4.00C towards the end of the 21st century will alter existing runoff regimes within watersheds. For SD watersheds that remain below freezing and continue to accumulate snowpack during the cold season, transport of fecal contamination will likely occur earlier in the year with greater intensity. Fecal coliform transport in summer is likely to decrease, especially in SD watersheds in which fecal contamination is driven by summer rainfall events. Snowmelt-dominant watersheds transitioning toward a RD runoff regime will experience less contamination during spring but increased contamination during late fall and winter. The extent to which these changes in runoff regime will influence surface water fecal contamination will vary among watersheds. Further investigation is required to identify factors that enhance or mitigate the association of surface water fecal contamination with rainfall and snowmelt-induced runoff in order to identify specific site vulnerability to changing seasonal contamination levels. Total precipitation within BC is projected to increase by 20-30% towards the end of the 21st century. The association of annual FC variability with snowmelt and rainfall variability was examined in order to assess the capacity of such increases to raise the level of surface water fecal contamination. Greater total annual and seasonal rainfall and/or river discharge increased surface water fecal contamination for 58% (11/19) of the sites examined. Hydro-meteorological variability influenced FC concentration during winter, the season of greatest precipitation, and spring, the season of greatest snowmelt, but not during summer or fall. Reduced contamination levels during the El Niño event in 2002/03 were associated with a mean reduction in river discharge during spring and summer. These associations suggest that the risk of increased surface water fecal contamination in response to higher precipitation is likely to be greatest in winter for RD watersheds and spring for SD watersheds, although the magnitude of impact will vary among sites. Climate change and land-use activities within watersheds have the capacity to alter the timing and amount of surface water fecal contamination. These factors are likely to act synergistically by increasing the presence and transport of fecal contaminants within watersheds. Such relationships should be carefully considered to aid the assessment and mitigation of the risk of source water contamination associated with land-use and climate change.
Graduate

碩士
國立中正大學
地震研究所暨應用地球物理研究所
96
Salmonella, Shigella and some opportunistic pathogens (Aeromonas, Citrobacter, Yersinia, Klebsiell, Serratia and Arcobacter, etc.) have emerged as waterborne pathogens of concern. The aim of this study was to examine the occurrence of bacterial pathogens and to identify the species of bacterial pathogens by biomolecular techniques in Taiwan surface watershed. We also evaluate different methods for detecting pathogens and investigated the relations between the pathogens and water quality parameters.The frequency of occurrence for Aeromonas spp. were 100% and 95.6% while analyzing by cultural method and direct extraction method, respectively. Five genotypes of Aeromonas spp. can be identified while combined multiples PCR and t-PCR. The frequency of occurrence for pathogenic Aeromonas were 78% and 58% in two selected watershed.The occurrence frequency was 28.9% for Shigella spp. for all collected water samples. The presence of shigella spp. and water quality parameters do not exhibit significant correlation. After sequencing analysis, eleven isolates were identified as S. flexneri 2a (68.8%) and five isolate was identified as S. flexneri 5 (31.2%) .The occurrence frequency was 42.2% for salmonella spp. for all collected water samples. High significant correlation was found between the presence of Salmonella and water turbidity. Eighteen positive water samples were identified as S. typhimurium but one sample was identified as S. enterica.The species of opportunistic pathogens isolated and identified from 8 surface watershed include Citrobacter freundii., Yersinia pseudotuberculosis , Yersinia enterocolitica, Klebsiell oxytoca., Serratia plymuthica and Arcobacter cryaerophilus.The presence of pathogens in Taiwan drinking watershed indicates the possibility of waterborne transmission in Taiwan if water is not adequately treated.