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1.
Int Microbiol ; 22(3): 325-336, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30810996

RESUMO

Soil microbial communities are an important component of biological diversity and terrestrial ecosystems which is responsible for processes such as decomposition, mineralization of nutrients, and accumulation of organic matter. One of the factors that provide information on the mechanisms regulating biodiversity is spatial scaling. We characterized the microbial communities using 16S rRNA gene sequences from DNA isolated from halite at various locations and correlated these to geographic distance in the Uyuni salt flat (Bolivia). Sequences from each site were analyzed to determine any spatial patterns of diversity, as well as to describe the microbial communities. Results suggest that different taxa are able to disperse over Uyuni's surface crust regardless of distance. As expected, ubiquitous taxa included members of Halobacteriaceae such as Haloarcula, Halorubrum, Halorhabdus, Halolamina, and halophilic bacteria Salinibacter, Halorhodospira, and unclassified members of the Gammaproteobacteria. Archaeal communities were homogeneous across the salt flat. In contrast, bacterial communities present strong local variations which could be attributed to external factors. Likely sources for these variations are the Rio Grande river influent in the south shore and the Tunupa volcano influencing the northern area.


Assuntos
Archaea/classificação , Bactérias/classificação , Biota , Microbiologia do Solo , Archaea/genética , Bactérias/genética , Bolívia , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Metagenômica , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
2.
J Water Health ; 16(6): 980-990, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30540272

RESUMO

In dry areas, the need for irrigation to ensure agricultural production determines the use of all available water sources. However, the water sources used for irrigation are often contaminated by untreated or minimally treated wastewater. Microbial risks from reusing wastewater for vegetable irrigation can be addressed by installing environmental barriers that pathogens must cross to reach humans in the reuse system. Knowledge of pathogen flows inside the system and pathogen removal potential is the first step towards devising a risk management strategy. This study assessed microbe prevalence in farming systems in the Bolivian highlands that use wastewater-polluted sources for irrigation of lettuce. Samples of soil, lettuce and different water sources used in the farming systems were taken during one crop season and concentrations of coliphages, Escherichia coli and helminth eggs were measured. The results showed high spread of these microorganisms throughout the whole system. There was a significant correlation between microbial quality of water and of the harvested produce for several microorganisms. The microbial prevalence in protected shallow wells was found to be significantly lower than in other water sources. These findings can help formulate feasible risk management strategies in contexts where conventional technologies for microbial removal are not possible.


Assuntos
Irrigação Agrícola , Microbiologia do Solo , Águas Residuárias , Microbiologia da Água , Bolívia , Produção Agrícola , Humanos , Eliminação de Resíduos Líquidos
3.
Water Sci Technol ; 68(12): 2698-703, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24355860

RESUMO

The objective of this study is to compare the removal of Taenia eggs to the removal of Ascaris eggs in a wastewater stabilization pond system consisting of three ponds in series, where the hydraulic residence time distribution has been characterized via a tracer study supported by computational fluid dynamics modeling. Despite a theoretical hydraulic retention time of 30 days, the peak dye concentration was measured in the effluent of the first pond after only 26 hours. The smaller-sized Taenia eggs were detected in higher concentrations than Ascaris eggs in the raw wastewater. Ascaris eggs were not detected in the pond system effluent, but 45 Taenia eggs/L were detected in the system effluent. If some of these eggs were of the species Taenia solium, and if the treated wastewater were used for the irrigation of crops for human consumption, farmers and consumers could potentially be at risk for neurocysticercosis. Thus, limits for Taenia eggs in irrigation water should be established, and precautions should be taken in regions where pig taeniasis is endemic. The results of this study indicate that the theoretical hydraulic retention time (volume/flow) of a pond is not always a good surrogate for helminth egg removal.


Assuntos
Cisticercose/etiologia , Cysticercus/isolamento & purificação , Hidrodinâmica , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/parasitologia , Poluentes da Água/isolamento & purificação , Animais , Bolívia , Cisticercose/parasitologia , Cysticercus/patogenicidade , Monitoramento Ambiental , Humanos , Modelos Teóricos , Qualidade da Água/normas
4.
PLoS Med ; 6(8): e1000125, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19688036

RESUMO

BACKGROUND: Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification method that has been disseminated globally. Laboratory studies suggest that SODIS is highly efficacious in inactivating waterborne pathogens. Previous field studies provided limited evidence for its effectiveness in reducing diarrhoea. METHODS AND FINDINGS: We conducted a cluster-randomized controlled trial in 22 rural communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5 y. A local nongovernmental organisation conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 y. Within the intervention arm 225 households (376 children) were trained to expose water-filled polyethyleneteraphtalate bottles to sunlight. Eleven communities (200 households, 349 children) served as a control. We recorded 166,971 person-days of observation during the trial representing 79.9% and 78.9% of the total possible person-days of child observation in intervention and control arms, respectively. Mean compliance with SODIS was 32.1%. The reported incidence rate of gastrointestinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year at risk in the control arm. The relative rate of diarrhoea adjusted for intracluster correlation was 0.81 (95% confidence interval 0.59-1.12). The median length of diarrhoea was 3 d in both groups. CONCLUSIONS: Despite an extensive SODIS promotion campaign we found only moderate compliance with the intervention and no strong evidence for a substantive reduction in diarrhoea among children. These results suggest that there is a need for better evidence of how the well-established laboratory efficacy of this home-based water treatment method translates into field effectiveness under various cultural settings and intervention intensities. Further global promotion of SODIS for general use should be undertaken with care until such evidence is available. TRIAL REGISTRATION: www.ClinicalTrials.govNCT00731497 Please see later in the article for Editors' Summary.


Assuntos
Diarreia/prevenção & controle , Desinfecção/métodos , Gastroenteropatias/epidemiologia , Luz Solar , Microbiologia da Água , Purificação da Água/métodos , Abastecimento de Água , Bolívia/epidemiologia , Pré-Escolar , Análise por Conglomerados , Países em Desenvolvimento , Diarreia/epidemiologia , Feminino , Promoção da Saúde , Inquéritos Epidemiológicos , Humanos , Incidência , Lactente , Cooperação do Paciente , Saúde da População Rural
5.
Gac. méd. boliv ; 29(2): 5-10, 2006. ilus
Artigo em Espanhol | LILACS | ID: lil-737733

RESUMO

Está establecido que existen dos especies distintas de amebas que originalmente fueron conocidas como Entamoeba Histolytica. Ellas son E. dispar (forma no patogénica) y E. histolytica (forma patogénica). La diferencia entre estos dos organismos es de gran importancia clínica desde que son morfológicamente indistinguibles. El diagnóstico diferencial de estas dos especies es esencial para la decisión del tratamiento y la salud pública. Se puede usar un método rápido de extracción de DNA directamente de especímenes suspendidos en formalina éter. La extracción de ADN fue usada para la identificación de las especies existentes en las herramientas por reacción de cadena polimerasa (PCR). Un total de 75 muestras recolectadas aleatoriamente fueron analizadas. Despues de la confirmación por PCR: 7/75 muestras resultaron positivas para E. histolytica, 60/75 muestras resultaron positivas para E. dispar y 8/75 resultaron negativas porque no amplificaron, pudiendo tratarse de otras amebas como E. hartmani. E. iodoamoeba, E. coli, etc. Con estos resultados podemos darnos cuenta de la magnitud de falsos positivos que se generan con los exámenes microscópicos. Estas observaciones implican que el uso del DNA extraído directamente a partir de concentración de quistes para amplificación por PCR, es una herramienta útil para obtener un diagnóstico sensitivo y preciso que puede ser aplicado incluso en epidemiología.


It has been established that two distinct species exist within what was originally known as Entamoeba histolytica. These are E. dispar (nonpathogenic form) and E. histolytica (pathogenic form). Differentiation of these two organisms is of great clinical importance since they are morphologically indistinguishable. Differential diagnosis of this two species is essential for treatment decision and public health knowledge. A simple and rapid DNA-extraction method that can be used directly on formalin-ether stool specimens. The extracted DNA was used for the identification of the species existing in the stools by polymerase chain reaction (PCR). A total of 75 randomly collected stool sample were analyzed. The samples analyzed by microscopic were 75, after confirmation by PCR: 7/75 samples resulting positive for E. histolytica, 60/75 samples resulting positive for E. dispar and 8/75 resulting negative because didn't amplify be able to be other amoebas like E. hartmani, E. iodoamoeba, E. coli, etc. With these results we can realize the magnitude of false positive that are generated with the microscopic exams. These observations imply that the use of the DNA extracted directly of the concentrate of cysts for PCR amplification is a useful tool for obtaining a sensitive and accurate diagnosis that can be applied even in epidemiology.


Assuntos
Entamebíase
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