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Digital polymerase chain reaction (dPCR) has emerged as a groundbreaking technology in molecular biology and diagnostics, offering exceptional precision and sensitivity in nucleic acid detection and quantification. This review highlights the core principles and transformative potential of dPCR, particularly in infectious disease diagnostics and environmental surveillance. Emphasizing its evolution from traditional PCR, dPCR provides accurate absolute quantification of target nucleic acids through advanced partitioning techniques. The review addresses the significant impact of dPCR in sepsis diagnosis and management, showcasing its superior sensitivity and specificity in early pathogen detection and identification of drug-resistant genes. Despite its advantages, challenges such as optimization of experimental conditions, standardization of data analysis workflows, and high costs are discussed. Furthermore, we compare various commercially available dPCR platforms, detailing their features and applications in clinical and research settings. Additionally, the review explores dPCR's role in water microbiology, particularly in wastewater surveillance and monitoring of waterborne pathogens, underscoring its importance in public health protection. In conclusion, future prospects of dPCR, including methodological optimization, integration with innovative technologies, and expansion into new sectors like metagenomics, are explored. [ABSTRACT FROM AUTHOR]

We have developed a new litmus paper test (DipTest) for detecting Escherichia coli (E. coli) in water samples by performing enzymatic reactions directly on the porous paper substrate. The paper strip consists of a long narrow piece of cellulose blotting paper coated with chemoattractant (at bottom edge), wax hydrophobic barrier (at the top edge), and custom formulated chemical reagents (at reaction zone immediately below the wax hydrophobic barrier). When the paper strip is dipped in water, E. coli in the water sample is attracted toward the paper strip due to a chemotaxic mechanism followed by the ascent along the paper strip toward the reaction zone due to a capillary wicking mechanism, and finally the capillary motion is arrested at the top edge of the paper strip by the hydrophobic barrier. The E. coli concentrated at the reaction zone of the paper strip will react with custom formulated chemical reagents to produce a pinkish-red color. Such a color change on the paper strip when dipped into water samples indicates the presence of E. coli contamination in potable water. The performance of the DipTest device has been checked with different known concentrations of E. coli contaminated water samples using different dip and wait times. The DipTest device has also been tested with different interfering bacteria and chemical contaminants. It has been observed that the different interfering contaminants do not have any impact on the DipTest, and it can become a potential solution for screening water samples for E. coli contamination at the point of source. [ABSTRACT FROM AUTHOR]

Forty-one bacterial strains isolated from the headbox water of two machines in a Canadian paper mill were associated with the genera Asticcacaulis, Acidovorax, Bacillus, Exiguobacterium, Hydrogenophaga, Pseudomonas, Pseudoxanthomonas, Staphylococcus, Stenotrophomonas based on the sequence of their 16S rRNA genes. The metabolic profile of these strains were determined using Biolog EcoPlate, and the bacteria were divided into four metabolic groups. Metabolic profiles of the bacterial communities colonizing the headbox water of two paper machines was also determined weekly over a 1 year period. The only compound that was not reduced by the bacterial community was 2-hydroxybenzoic acid. Utilization frequency of the other carbon sources in the Biolog EcoPlate ranged from 3 to 100%. The metabolic profiles of the bacterial community did not vary considerably between the two paper machines. However, the metabolic profile varied among the sampling dates. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is shed in the stool of infected individuals and can be detected in sewage and wastewater contaminated with infected stool. This study is aimed at detecting the virus and its potential survival in sewage and wastewater in Ghana. The cross-sectional study included samples from 16 validated environmental surveillance sites in 7 regions of Ghana. A total of 354 samples composed of wastewater (280) and sewage (74) were collected from November 2020 to November 2022. Overall, 17% of the samples were positive for SARS-CoV-2 by real-time PCR, with 6% in sewage and 11% in wastewater. The highest number of positive samples was collected from the Greater Accra Region (7.3%) with the least recorded in the Bono East Region (0.6%). Further characterization of the positive samples using the next-generation sequencing (NGS) approach yielded two variants: Alpha (B.1.1.7) and Delta (AY.36). Attempts to isolate SARS-CoV-2 in the Vero cell line were not successful probably due to the low viral load concentrations (Ct values > 35) or prolonged exposure to high temperatures rendering the virus noninfectious. Our findings suggest that SARS-CoV-2 RNA in sewage and wastewater may not be infectious, but the prevalence shows that the virus persists in the communities within Ghana. [ABSTRACT FROM AUTHOR]

Simple Summary: In biofloc technology systems, organic matter and inorganic substances accumulate in the culture unit mainly due to low water exchange, feed input, high stocking densities, and the level of organic carbon that subsequently increase the bacterial biomass. The organic and inorganic matter in suspension are maintained in a limited concentration to avoid negative effects on animal performance and water quality. This requires the occasional removal of excess solids, which produces an effluent enriched in nutrients, such as nitrogen and phosphorus. The use of integrated aquaculture in which the residues of one species are used as a source of nutrients for another species is an approach which aims to minimize this production of waste. Still, there are aspects of integrated cultures that have to be studied, such as the provision of feed for the different species. Therefore, we evaluated the addition or not of fish feed and microalgae in an integrated shrimp and fish culture regarding animal growth performance and water quality. We found that biofloc is nutritive for fish, but feed is necessary to improve its growth. Moreover, microalgae improved fish survival. However, both of factors did not affect the solids production. This study aims to evaluate a Pacific white shrimp and Nile tilapia integrated system using biofloc technology with or without the addition of the microalgae Scenedesmus obliquus and with or without fish feed supplementation in a two-factor 62-day experiment. The shrimp (2.16 ± 0.01 g) were reared under a density of 400 shrimp m−3 and the fish (1.53 ± 0.12 g) were reared under a density of 522 fish m−3. The microalgae was added to the culture water two times a week. Growth performance, sludge production, and water microbiology were evaluated. Fish feed and the microalgae addition improved fish final biomass in 58% and 14%, respectively (p < 0.05). Fish survival was significantly higher when microalgae was added (93.9 ± 1.8%) compared with the treatments without microalgae addition (86.2 ± 7.6%) (p < 0.05). The yield of the overall system was higher in the treatments with fish feed supplementation (4.2 ± 0.2 kg m−3) compared with no addition (3.9 ± 0.2 kg m−3) (p < 0.05). These results suggest that fish feed supplementation at the rate of 1% of the biomass and microalgae inoculation can improve fish growth performance and system yield, without affecting sludge production and water microbiology. This work is an expansion of a conference paper with the same title. [ABSTRACT FROM AUTHOR]

A preface to the journal "Hydrobiologia" is presented.

Previous studies have demonstrated that benthic macro-invertebrate bioturbation can influence the remobilization of uranium initially associated with freshwater sediments resulting in a high release of this pollutant through the overlying water column. Giving the potential negative effects on aquatic biocenosis and the global ecological risk, it appeared crucial to improve our current knowledge concerning the uranium biogeochemical behaviour in sediments. The present study aimed to assess the biogeochemical modifications induced by Tubifex tubifex (Annelida, Clitellata, Tubificidae) bioturbation within the sediment permitting to explain such a release of uranium. To reach this goal, uranium distribution between solid and solute phases of a reconstructed benthic system (i.e. in mesocosms) inhabited or not by T. tubifex worms was assessed in a 12 day laboratory experiment. Thanks notably to fine resolution (mm-scale) measurements (e.g. DET gels probes for porewater, bioaccumulation in worms) of uranium and main chemical species (iron, sulfate, nitrate, nitrite), this work permitted (i) to confirm that the removal of bottom sediment particles to the surface through the digestive tract of worms greatly favours the oxidative loss of uranium in the water column, and (ii) to demonstrate that both uranium contamination and bioturbation of T. tubifex substantially influence major microbial-driven biogeochemical reactions in sediments (e.g. stimulation of denitrification, sulfate-reduction and iron dissolutive reduction). This study provides the first demonstration of biogeochemical modifications induced by bioturbation in freshwater uranium-contaminated sediments. [ABSTRACT FROM AUTHOR]

The aim of this research was to make the first depth profiles of the microbial assimilation of methanol carbon, and its oxidation to carbon dioxide and use as an energy source from the micro-layer to 1000 m. Some of the highest reported methanol oxidation rate constants of 0.5-0.6 d-1 were occasionally found in the micro-layer, and immediately underlying waters (10 cm depth), albeit these samples also showed the greatest heterogeneity compared to other depths down to 1000 m. Methanol uptake into the particulate phase was exceptionally low in micro-layer samples, suggesting that any methanol utilised by microbes in this environment is for energy generation. The sea surface micro-layer and 10 cm depth also showed a higher proportion of bacteria with a low DNA content, and bacterial leucine uptake rates in surface micro-layer samples were either less than, or the same as those in the underlying 10 cm layer. The average methanol oxidation and particulate rates were however statistically the same throughout the depths sampled, although the later were highly variable in the near surface 0.25-2m compared to deeper depths. The statistically significant relationship demonstrated between uptake of methanol into particles and bacterial leucine incorporation suggests that heterotrophic bacteria use methanol carbon for cellular growth, but the lack of relationships observed with methanol oxidation, perhaps suggest that a wider group of marine microbes use methanol for energy generation. Whilst the statistically significant relationship observed between the uptake of methanol into cell particles and the numbers of Prochlorococcus during diel experiments could also suggest that this abundant group of marine cyanobacteria are capable of mixotrophy, using methanol as a carbon source for growth. We conclude that microbial methanol uptake rates, i.e., loss from seawater are highly variable, particularly close to the seawater surface, which could significantly impact upon seawater concentrations and hence the air-sea flux. [ABSTRACT FROM AUTHOR]

As a consequence of global change, modifications in the interaction among abiotic stressors on aquatic ecosystems have been predicted. Among other factors, UVR transparency, nutrient inputs and shallower epilimnetic layers could alter the trophic links in the microbial food web. Currently, there are some evidences of higher sensitiveness of aquatic microbial organisms to UVR in opaque lakes. Our aim was to assess the interactive direct and indirect effects of UVR (through the excretion of organic carbon -- EOC -- by algae), mixing regime and nutrient input on bacterial metabolism We performed in situ short-term experiments under the following treatments: full sunlight (UVR+ PAR, > 280 nm) vs. UVR exclusion (PAR only, > 400 nm); ambient vs. nutrient addition (phosphorus (P; 30 µg PL-1) and nitrogen (N; up to final N:P molar ratio of 31)); and static vs. mixed regime. The experiments were conducted in three high-mountain lakes of Spain: Enol [LE], Las Yeguas [LY] and La Caldera [LC] which had contrasting UVR transparency characteristics (opaque (LE) vs. clear lakes (LY and LC)). Under ambient nutrient conditions and static regimes, UVR exerted a stimulatory effect on heterotrophic bacterial production (HBP) in the opaque lake but not in the clear ones. Under UVR, vertical mixing and nutrient addition HBP values were lower than under the static and ambient nutrient conditions, and the stimulatory effect that UVR exerted on HBP in the opaque lake disappeared. By contrast, vertical mixing and nutrient addition increased HBP values in the clear lakes, highlighting for a photoinhibitory effect of UVR on HBP. Mixed regime and nutrient addition resulted in negative effects of UVR on HBP more in the opaque than in the clear lakes. Moreover, in the opaque lake, bacterial respiration (BR) increased and EOC did not support the bacterial carbon demand (BCD). In contrast, bacterial metabolic costs did not increase in the clear lakes and the increased nutrient availability even led to higher HBP. Consequently, EOC satisfied BCD in the clear lakes, particularly in the clearest one [LC]. Our results suggest that the higher vulnerability of bacteria to the damaging effects of UVR may be particularly accentuated in the opaque lakes and further recognizes the relevance of light exposure history and biotic interactions on bacterioplankton metabolism when coping with fluctuating radiation and nutrient inputs. [ABSTRACT FROM AUTHOR]

Thaumarchaeota are amongst the most abundant microorganisms in aquatic environments, however, their metabolism in marine sediments is still debated. Labeling studies in marine sediments have previously been undertaken, but focused on complex organic carbon substrates which Thaumarchaeota have not yet been shown to take up. In this study, we investigated the activity of Thaumarchaeota in sediments by supplying different 13C-labeled substrates which have previously been shown to be incorporated into archaeal cells in water incubations and/or enrichment cultures. We determined the incorporation of 13C-label from bicarbonate, pyruvate, glucose and amino acids into thaumarchaeal intact polar lipid-glycerol dibiphytanyl glycerol tetraethers (IPL-GDGTs) during 4-6 day incubations of marine sediment cores from three different sites on the Iceland Shelf. Thaumarchaeal intact polar lipids were detected at all stations and concentrations remained constant or decreased slightly upon incubation. No 13C incorporation in any IPL-GDGT was observed at stations 2 (clay-rich sediment) and 3 (organic-rich sediment). In bacterial/eukaryotic IPL-derived fatty acids at station 3, contrastingly, a large uptake of 13C label (up to +80‰) was found. 13C was also respired during the experiment as shown by a substantial increase in the 13C content of the dissolved inorganic carbon. In IPL-GDGTs recovered from the sandy sediments at station 1, however, some enrichment in 13C (1-4‰) was detected after incubation with bicarbonate and pyruvate. The low incorporation rates suggest a low activity of Thaumarchaeota in marine sediments and/or a low turnover rate of thaumarchaeal IPL-GDGTs due to their low degradation rates. Cell numbers and activity of sedimentary Thaumarchaeota based on IPL-GDGT measurements may thus have previously been overestimated. [ABSTRACT FROM AUTHOR]

Methane concentrations in the stratified water column of the Gotland Deep (Central Baltic Sea) show a strong gradient from high values in the saline deep water (max. 504 nM) to low concentrations in the less dense, brackish surface water (about 4 nM). The steepest gradient is present within the redoxcline (between 115 and 135m water depth) that separates the anoxic deep part from the oxygenated surface water, implying a methane consumption rate of 0.28 nMd-1 . The process of microbial methane oxidation within the redoxcline is mirrored by a shift of the stable carbon isotope ratio of methane between the bottom water (δ13C CH4=-82.4‰) and the suboxic depth interval (δ13C CH4=-38.7‰). A water column sample from 100m water depth was studied to identify the microorganisms responsible for the methane turnover at the redoxcline. Notably, methane monoxygenase gene expression analyses for the specific water depth demonstrated that accordant methanotrophic activity was due to only one microbial phylotype. An imprint of these organisms on the particular organic matter was revealed by distinctive lipid biomarkers showing bacteriohopanepolyols and lipid fatty acids characteristic for aerobic type I methanotrophic bacteria (e.g. 35- aminobacteriohopane-30,31,32,33,34-pentol). In conjunction with earlier findings, our results support the idea that biogeochemical cycles in Central Baltic Sea redoxclines are mainly driven by only a few microbial key species. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated the effects of different environments on the filtering rate (FR), mortality, and biodeposition (BD) of the freshwater mussel Unio douglasiae in bloom waters containing the toxic cyanobacterium Microcystis aeruginosa. The mean FR of 19 selected individuals (shell length, 5.0–9.8 cm) was 0.30 ± 0.03 L g − 1 h − 1 (range = 0.24 – 0.35 L g − 1 h − 1 ). Shell length was strongly correlated with both net and gross BD of mussels (P < 0.0001). The mean FR was higher in river water (0.405 ± 0.052 L g − 1 h − 1 ) than in lake water (0.304 ± 0.051 L g − 1 h − 1 ). In contrast, the BD of mussels was higher in RW (0.671 ± 0.609 mg g − 1 h − 1 ) than in LW (0.275 ± 0.027 mg g − 1 h − 1 ). For algal species, the FR of mussels ranged from 0.114 ± 0.024 to 0.553 ± 0.019 L g − 1 h − 1 . The FR of U. douglasiae was higher in river water (mainly diatoms), whereas BD was higher in lake water (mainly Microcystis). U. douglasiae did not prefer toxic M. aeruginosa, which was significantly accumulated in pseudofaeces and faeces. The maximum FR of U. douglasiae in algal bloom water was recorded at a water temperature of 25°C and water depth of 50 cm. Moreover, the in situ mortality of U. douglasiae was strongly affected by water temperature and nitrogen concentration. Overall, U. douglasiae can enhance water quality in eutrophic areas by removing dominant cyanobacteria, although its removal efficiency depends on environmental parameters and site of introduction. [ABSTRACT FROM AUTHOR]

Low economic profit usually reduces the incentive of producers to operate their wastewater treatment technologies effectively. It is necessary to investigate the performance of environmentally friendly production technologies that reduce wastewater discharges and generate economic outputs simultaneously (EPTWs) in China over the past decade. In this paper, we apply the Malmquist-Luenberger productivity index widely used in the field of economics to evaluate the productivity change of EPTWs for 30 administrative provinces in China during 2003–2015. The pathways of the productivity change are further identified by decomposing the productivity index into two components: technological change and technical efficiency change. The results show that China’s environmental productivity index associated with wastewater reduction had undergone a downward trend, and evident spatial disparities are observed among the 30 provincial regions. Moreover, the changes of China’s environmental productivity over the whole studied period can mainly be attributed to technological progress, while the technical efficiency component has contributed little, although its annual contributing rate is in an increasing trend. [ABSTRACT FROM AUTHOR]

This paper attempts to evaluate the Malaysian water quality indexing method that has been criticized for its ineffectiveness. The indexing method is referred to as the Water Quality Index of the Department of Environment, Malaysia (DOE-WQI). This index was assessed against two other indices (River Ganga Index and Minimal Water Quality Index (WQImin)) and a modified DOE-WQI was also proposed. DOE-WQI and WQImin are physicochemical indices, whereas the River Ganga Index and modified DOE-WQI are indices with the inclusion of a microbiological parameter. The assessment was conducted based on the water quality of tropical rivers in Malaysia, with specific reference to Sarawak River and its tributaries. Water quality in terms of pH, dissolved oxygen, conductivity, turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, ammoniacal nitrogen, and fecal coliform count (FCC) was measured from 18 stations in December 2015, January 2016, and March 2016. Generally, the river was characterized with high FCC with the four indices significantly correlated. The results demonstrated the shortcomings of the existing DOE-WQI; the physicochemical index assigned water quality to a better class than its actual conditions without taking into consideration the FCC. [ABSTRACT FROM AUTHOR]

Here, we examine the geobiological response to a whole-lake alum (aluminum sulfate) treatment (2016) of Base Mine Lake (BML), the first pilot-scale pit lake established in the Alberta oil sands region. The rationale for trialing this management amendment was based on its successful use to reduce internal phosphorus loading to eutrophying lakes. Modest increases in water cap epilimnetic oxygen concentrations, associated with increased Secchi depths and chlorophyll-a concentrations, were co-incident with anoxic waters immediately above the fluid fine tailings (FFT) layer post alum. Decreased water cap nitrate and detectable sulfide concentrations, as well as increased hypolimnetic phospholipid fatty acid abundances, signaled greater anaerobic heterotrophic activity. Shifts in microbial community to groups associated with greater organic carbon degradation (i.e., SAR11-LD12 subclade) and the SRB group Desulfuromonodales emerged post alum and the loss of specialist groups associated with carbon-limited, ammonia-rich restricted niches (i.e., MBAE14) also occurred. Alum treatment resulted in additional oxygen consumption associated with increased autochthonous carbon production, watercap anoxia and sulfide generation, which further exacerbate oxygen consumption associated with on-going FFT mobilized reductants. The results illustrate the importance of understanding the broader biogeochemical implications of adaptive management interventions to avoid unanticipated outcomes that pose greater risks and improve tailings reclamation for oil sands operations and, more broadly, the global mining sector. [ABSTRACT FROM AUTHOR]

This study tests if rainfall regime and estuary hydrodynamics affect ecological picocyanobacterial patterns. We statistically related rainfall with picocyanobacteria (flow cytometry) and water quality data from a seven-year-long survey of Guanabara Bay (GB). The quality of GB's water varies spatially, depending on pollution hotspots, tidal influence, and water circulation patterns. It also varies seasonally, depending on the rainfall regime. Our results showed that rainfall regularly makes water quality and microbiology of the inner estuarine regions more like the tributaries' environment. We found that phycocyanin-rich and phycoerythrin-rich picocyanobacterial abundances are associated with riverine and marine waters, respectively. Besides affecting GB's water quality, rainfall governs its picocyanobacterial distribution and ecology. Thus, climate changes may influence the balance of the picocyanobacterial groups in tropical estuaries. Furthermore, the omnipresence of picocyanobacterial groups found in GB, such as Synechococcus and Cyanobium, highlights their ecological role in tropical estuaries, as seen in the open ocean. [ABSTRACT FROM AUTHOR]

Water is one of the most important natural resource, a social requirement and an important factor in the ecological balance. Water from springs is good for direct consumption if the soil is not contaminated. The population, who is not benefiting from the centralized water, is supplied in different area from springs. Water from springs is good for direct consumption if the area around groundwater is not contaminated. Groundwater pollution, caused by human activities related to the agriculture, industry and population growth, is a current problem with serious consequences to human health. The aim of this paper was to assess the physico-chemical and microbiological qualities of springs water from Abrud-Câmpeni area, Alba County, Roamnia. The water samples were taken in 2018 from 11 functional springs. Of these, only three sources are potable, the rest of the springs are microbiologically contaminated. The average concentration of NO3- - in the investigated springs from Abrud-Câmpeni area is 6.1 mg/l. Monthly, between January and December 2018, the variation of the nitrate content in the water from the spring Lucia (Sohodol village) was also monitored. Fluctuations were observed with maximum in the cold season (February), 4.37 mg/l, and minimum in the summer (August), 2.14 mg/l. In order to identify the factors that lead to the variation of the NO3- - content in water, statistical mathematical models were developed. The parameters studied were: atmospheric temperature, the amount of precipitation, respectively the freeze/thaw cycle. The concordance indicators demonstrated a satisfactory correlation between the variation of those factors and the variation of the NO3- - content in water. [ABSTRACT FROM AUTHOR]

Microbial contamination in urban stormwater is one of the most widespread and challenging water quality issues in developed countries. Low impact development (LID) best management practices (BMPs) restore pre-urban hydrology by treating and/or harvesting urban runoff and stormwater, and can be designed to remove many contaminants including pathogens. One particular type of LID BMP, stormwater biofilters (i.e., vegetated media filters, also known as bioinfiltration, bioretention, or rain gardens), is becoming increasingly popular in urban environments due to its multiple co-benefits (e.g., improved hydrology, water quality, local climate and aesthetics). However, increased understanding of the factors influencing microbial removal in biofilters is needed to effectively design and implement biofilters for microbial water quality improvement. This paper aims to provide a holistic view of microbial removal in biofilter systems, and reviews the effects of various design choices such as filter media, vegetation, infauna, submerged zones, and hydraulic retention time on microbial removal. Limitations in current knowledge and recommendations for future research are also discussed. [ABSTRACT FROM AUTHOR]

The results of five-year (2008-2012) hydrochemical research of the Poprad river, the right bank tributary to the Dunajec, were analyzed in the paper. The Poprad, 167 km long and with the catchment area of 2077.3 km2, flows for over 100 km through the territory of Slovakia, along the length of 31.1 km is a transboundary river, whereas its 31.0 km long reach is situated in Poland. Concerning its abiotic character, it is an eastern upland river of type 15. The research was conducted in three measurement-control points: 1) located in Leluchów on the Polish-Slovak border at 61.1 kilometer of the river course, 2) in Piwniczna-Zdrój - 23.9 km and 3) in Stary Sącz - 2.9 km before the Poprad outlet to the Dunajec. 21 physicochemical indices and 2 microbiological indicators were assessed in the water samples once a month using referential methods. The paper assesses changes of water quality classes and its usable values along the analyzed Poprad river reach. Moreover, statistical differences between the values of individual indices assessed in various measurement-control points were estimated by means of Mann-Whitney U nonparametric test. On the basis of the conducted analyses of the empirical data it was stated that due to the physicochemical indices, water quality along the whole length of the analyzed river reach was good (class II) - in points 1 and 3 it was determined by mean concentration of total suspended solids, whereas in point 2 COD-Mn values. [ABSTRACT FROM AUTHOR]

Growing areas of sealed surfaces, rising water needs due to industry development, increasing populations, and climatic changes affect precipitation patterns and form a vision of the future in which meteoric water storage may become almost an obligatory activity. The aim of this paper was to identify the amounts and, to some degree, the quality of microorganisms present in rainwater collected from different types of rooftops of utility buildings in the spring-summer season. Apart from the classic culture plate method complemented by flow cytometry. The results of performed analyses explicitly show that rainwater collected from rooftops and directly from air prove to be microbially contaminated to a substantial degree, which includes pathogenic coliforms and faecal streptococci. Waters collected after dry periods also contained bacteria like Clostridium perfingens. The findings rule out the possibility of using rainwater collected from roof surfaces of utility buildings before its treatment. [ABSTRACT FROM AUTHOR]

Background: Antibiotic resistance has been referred to as 'the greatest malice of the 21st century' and a global action plan was adopted by the World Health Assembly in 2015. There is a wealth of independent studies regarding antibiotics and resistant bacteria in humans, animals and their environment, however, integrated studies are lacking, particularly ones that simultaneously also take into consideration the health related behaviour of participants and healthcare providers. Such, 'One health' studies are difficult to implement, because of the complex teamwork that they entail. This paper describes the protocol of a study that investigates 'One health' issues regarding antibiotic use and antibiotic resistance in children and their environment in Indian villages.Methods/design: Both quantitative and qualitative studies are planned for a cohort of children, from 6 villages, and their surrounding environment. Repeated or continues data collection is planned over 2 years for quantitative studies. Qualitative studies will be conducted once. Studies include parents' health seeking behavior for their children (1-3 years of age at the onset), prescribing pattern of formal and informal healthcare providers, analysis of phenotypic antibiotic resistance of Escherichia coli from samples of stool from children and village animals, household drinking water, village source water and waste water, and investigation on molecular mechanisms governing resistance. Analysis of interrelationship of these with each other will also be done as basis for future interventions. Ethics approval has been obtained from the Institutional Ethics Committee R.D. Gardi Medical College, Ujjain, India (No: 2013/07/17-311).Discussion: The findings of the study presented in this protocol will add to our knowledge about the multi-factorial nature of causes governing antibiotic use and antibiotic resistance from a 'One health' perspective. Our study will be the first of its kind addressing antibiotic use and resistance issues related to children in a One-health approach, particularly for rural India. [ABSTRACT FROM AUTHOR]

Water is one of the prime necessities of life. We can hardly live for a few days without water. In a man's body, 70-80% is water. Cell, blood, and bones contain 90%, 75%, and 22% water, respectively. The general survey reveals that the total surface area of earth is 51 crore km2 out of which 36.1 crore km2 is covered sea. In addition to this, we get water from rivers, lakes, tanks, and now on hills. In spite of such abundance, there is a shortage of soft water in the world. Physicochemical parameter of any water body plays a very important role in maintaining the fragile ecosystem that maintains various life forms. Present research paper deals with various water quality parameter, chlorides, dissolved oxygen, total iron, nitrate, water temperature, pH, total phosphorous, fecal coli form bacteria, and adverse effect of these parameters on human being. [ABSTRACT FROM AUTHOR]

Good quality water is odourless, colourless, and free from faecal pollution, and a satisfactory safe supply must be made available to consumers. The study assessed consumer preference and quality of sachet water sold and consumed in the Sunyani Municipality of Ghana. A cross-sectional study design was used, and data were collected using a structured questionnaire from a sample size of 500 respondents. A total of twenty (20) samples of sachet water commonly sold and consumed in the Sunyani Municipality were also collected and analyzed for bacteriological and physicochemical parameters. Out of these 20 samples, 10 samples of sachet water were collected from the production site and the other 10 samples from the market site. Results showed that respondents' choice of sachet water was based on several indicators. While 70% (350/500) of consumers indicated that sachet water had taste, 58% (290/500) of them were not enthused when the water had colour. Using smell as an indicator, 71% of consumers have had an experience with sachet water smell being questionable. Water taste (p < 0.001), colour of water (p < 0.001), smell (p < 0.001), and increase in cost (p < 0.001) were found as determinants of consumer preference. Consumers who said the colour of water informed their decision when buying sachet water were seven times more likely to have a preference for a particular brand (OR 7.057, CI: 4.474–11.133). Those who checked for expiry dates when buying water (OR 4.871, CI: 3.110–7.628) and those who looked out for Food and Drugs Authority stamp (OR 4.433, CI: 2.806–7.003) were both four times more likely to have a preference for a particular brand. Water quality tests also indicated that 30% of all water samples collected from the production site were contaminated with total coliforms and 50% of sachet water samples collected from the markets were also contaminated with coliforms. The same brands of sachet water that contained total coliforms from the production site were the same brands that contained total coliforms selected from the market. From this study, only total coliforms other than Escherichia coli were detected in the water samples analyzed. It was observed that the evaluated physicochemical parameters of the water analyzed were within the accepted WHO limits. It is recommended that consumers be educated about the indicators to look out for when buying sachet water and, also, that regulatory bodies be empowered to ban the sale of unwholesome brands of sachet water on the market. [ABSTRACT FROM AUTHOR]

Background. Freeze-thaw influences soil-dissolved nitrogen (N) pools due to variations in bacterial communities in temperate regions. The availability of soil water is important to soil biogeochemical cycles under frozen conditions. However, it is unclear how soil water content (SWC) mediates the effects of freeze-thaw on soil-dissolved N pools and bacterial communities. Method. In this study, freeze-thaw microcosms were incubated at three levels of SWC, including 10% (air-dried soils), 15% (natural SWC), and 30% (wet soils). In addition to measuring soil-dissolved N pools, variations in bacterial communities were examined using high-throughput sequencing. Results and Conclusions. Total dissolved N (TDN), NO3--N, NH4+-N, microbial biomass N (MBN), and net N mineralization rate (NNMR) were significantly influenced by SWC, freeze-thaw, and their interaction (NH4+-N excluded). N immobilization was inhibited under both low and high SWC, which was accompanied by varied bacterial community composition. However, only higher SWC substantially modified the freeze-thaw effects on the soil-dissolved N pools, characterized by a decrease in N mineralization (especially for the content of NO3--N and NNMR) and an increase in N immobilization (MBN). These scenarios could be significantly correlated to variations in bacterial community composition based on redundancy analysis, especially by species belonging to Bacteroidetes, Nitrospirae, Alphaproteobacteria, Gemmatimonadetes, and Verrucomicrobia (Spearman's correlations). In conclusion, bacterial species passed through biotic (bacterial species) and abiotic filters (soil N pools) in response to freeze-thaw under varied SWC. [ABSTRACT FROM AUTHOR]

In this study, a yeast strain with an outstanding NH3-N degradation ability was isolated from the sediment of a black-odor water channel in Guangdong Province, China. Based on phenotypic and phylogenetic analysis, this strain was identified as Pichia kudriavzevii GW1. The optimum conditions for NH3-N degradation by the GW1 strain were as follows: 0.3% inoculum concentration, 1.5 L/min aeration, pH 7, and a temperature of 35°C. Under optimized conditions, the GW1 strain degraded 95.5% of the NH3-N. The strain was then added to simulated black-odor water under optimal degradation conditions to investigate changes to the bacterial community over time. 16S rRNA sequencing of samples collected on days 0, 7, 14, and 21 showed that, in the presence of the GW1 strain, the relative abundances of the phyla Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes increased in the black-odor water. In addition, the relative abundance of Propionivibrio, a known NH3-N degrading genus, increased. This study will facilitate the use of microbiological methods to repair black-odor water. [ABSTRACT FROM AUTHOR]

Keywords: microbialites; microbiome; geobiology; meta-omics approaches; microbiology In the paper by De Anda et al., the authors used metagenomic techniques to examine the specific interactions between taxa in response to environmental perturbations in the freshwater microbialites of Cuatros Ciénegas in Mexico. [Extracted from the article]

Pseudoalteromonas is a globally distributed marine-associated genus that can be found in a broad range of aquatic environments, including in association with macroalgal surfaces where they may take advantage of these rich sources of polysaccharides. The metabolic systems that confer the ability to metabolize this abundant form of photosynthetically fixed carbon, however, are not yet fully understood. Through genomics, transcriptomics, microbiology, and specific structure-function studies of pathway components we address the capacity of newly isolated marine pseudoalteromonads to metabolize the red algal galactan carrageenan. The results reveal that the κ/ι-carrageenan specific polysaccharide utilization locus (CarPUL) enables isolates possessing this locus the ability to grow on this substrate. Biochemical and structural analysis of the enzymatic components of the CarPUL promoted the development of a detailed model of the κ/ι-carrageenan metabolic pathway deployed by pseudoalteromonads, thus furthering our understanding of how these microbes have adapted to a unique environmental niche. Hettle et al. investigate the ability of marine Pseudoalteromonas sp. to metabolise carrageenan, a polysaccharide abundant in red algae. They isolate and characterise previously unstudied strains and find that the recently identified κ/ι-carrageenan specific polysaccharide utilization locus (CarPUL) is required for growth on carrageenan, and biochemically map out many of the steps. [ABSTRACT FROM AUTHOR]

The bacteriological characteristics of rainwater harvested from a typical rooftop were progressively studied for a period of nine (9) months. The study area, Oyoko, is a rural community considered as a typical farming area and located about 30 km from Kumasi, the capital city of Ashanti Region of Ghana. The collected rainwater samples were analyzed for Escherichia coli (E. coli) and salmonella. The entire E. coli counts varied from 0-60 CFU/100 ml and were absent on 39 observations out of total of 84 observations (replicate samples), representing 46.4%. Whiles the entire salmonella counts ranged from 0-78 CFU/100ml and only 10 observations out of the 84 were absent, which represents 11.9%. Both E. coli and salmonella showed higher concentration during early stages of continuous rainfall but, progressively reduced during later part of rainfall. The main cause of this phenomenon can be attributed to the deposition and accumulation of pollutant materials on the rooftop and catchment areas typically during the dry seasons as a result of wind-blown dirt particles and other environmental pollutants. The high bacteriological constituents in the early-stage harvested rainwater consequently have some proven significant health implications from their direct consumption. It is therefore imperative for the community to know the best time interval to harvest their rainwater as rainfall progresses, and also know any health implications associated with the harvested rainwater that goes into their storage tanks for consumption through progressive monitoring of the quality. [ABSTRACT FROM AUTHOR]

The field of treatment wetlands (TWs) is rapidly expanding and, arguably, is tasked with studying and understanding one of the most complex water treatment systems available. Microbial communities are generally considered to be responsible for the majority of wastewater constituent degradation in TWs. However, they are also known to be spatially heterogeneous, temporally dynamic, as well as structurally and functionally diverse. Presented here is a meta-analysis of all peer reviewed TW journal articles which utilized a microbial community assessment methodology over the period of 1988 to July 2016. A total of 1101 papers were reviewed, 512 from 1988 to 2012, 215 of which included a microbial community assessment aspect and were subsequently classified as representing past research, and 589 from 2013 to July 2016, 196 of which were classified as representing current TW microbial community research. In general, TW microbial community research has increased over time, with a marked surge in the past four years. Microbial community structure is currently the most commonly used methodological type followed by activity, enumeration and function, respectively. Areas of research focus included nitrogen transformations (156), organic degradation (33), and emerging contaminants (32), with general characterization studies also accounting for a significant proportion (243). Microbial communities from a range of TW systems have been investigated over the last four years with meso-scale (10-1000 L) being the most commonly studied system size followed by large-scale (>100,000 L), micro-scale (<10 L), and pilot-scale (1000-100,000 L). Free water surface flow (SF), horizontal subsurface flow (HF), and vertical flow (VF) systems are being studied in approximately equal proportions with the majority of studies focused on gaining fixed media/biofilm samples for analysis (rather than from the rhizosphere or interstitial water). Looking at efforts from a regional perspective shows Asia to be publishing the majority of research with a main focus on VF systems and structural community assessment. European and North American studies are generally more evenly distributed among structure, function, activity, and enumeration with the majority of studies completed on HF systems. South America, Africa, and Oceania published fewer studies but focused on structural community assessment with a selection of HF, SF and VF investigations. Great strides are being made in the field of microbial community assessment in TWs with functional assessment methods being developed, better utilized, and being related directly to water treatment. The use of high-powered metagenomics sequencing such as Illumina HiSeq instrumentation is on the rise, as is the development and utilization of functional assays such as DNA microarrays and community level physiological profiling allowing for more complete community assessment. Used in concert with activity, enumeration and newly implemented stable isotope methodologies, the field of TWs is certainly moving away from the black-box understanding of the past. [ABSTRACT FROM AUTHOR]

Background The aim of this paper was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for rapid, sensitive and inexpensive detection of astrovirus. Results The detection limit of LAMP using in vitro RNA transcripts was 3.6×10 copies•μL-1, which is as sensitive as the presently used PCR assays. However, the LAMP products could be identified as different colors with the naked eye following staining with hydroxynaphthol blue dye (HNB). No cross-reactivity with other gastroenteric viruses (rotavirus and norovirus) was observed, indicating the relatively high specificity of LAMP. The RT-LAMP method with HNB was used to effectively detect astrovirus in reclaimed water samples. Conclusions The LAMP technique described in this study is a cheap, sensitive, specific and rapid method for the detection of astrovirus. The RT-LAMP method can be simply applied for the specific detection of astrovirus and has the potential to be utilized in the field as a screening test. [ABSTRACT FROM AUTHOR]

The ocean pH is decreasing in response to the increasing anthropogenic CO SB 2 sb emissions (Ocean Acidification; OA). This clear trend of ocean warming and acidification was documented in the fifth Assessment Report (AR5) by Intergovernmental Panel on Climate Change (IPCC). Keywords: microbial community; marine environment; ecosystem; warming; ocean acidification EN microbial community marine environment ecosystem warming ocean acidification 1 3 3 08/12/21 20210809 NES 210809 The World Ocean is undergoing rapid and substantial changes, particularly, in terms of warming and acidification. [Extracted from the article]

The Water-associated Disease Index (WADI) was developed to identify and visualize vulnerability to different water-associated diseases by integrating a range of social and biophysical determinants in map format. In this study vulnerability is used to encompass conditions of exposure, susceptibility, and differential coping capacity to a water-associated health hazard. By assessing these conditions, the tool is designed to provide stakeholders with an integrated and long-term understanding of subnational vulnerabilities to water-associated disease and contribute to intervention strategies to reduce the burden of illness. The objective of this paper is to describe and validate the WADI tool by applying it to dengue. A systemic ecohealth framework that considers links between people, the environment and health was applied to identify secondary datasets, populating the index with components including climate conditions, land cover, education status and water use practices. Data were aggregated to create composite indicators of exposure and of susceptibility in a Geographic Information System (GIS). These indicators were weighted by their contribution to dengue vulnerability, and the output consisted of an overall index visualized in map format. The WADI was validated in this Malaysia case study, demonstrating a significant association with dengue rates at a sub-national level, and illustrating a range of factors that drive vulnerability to the disease within the country. The index output indicated high vulnerability to dengue in urban areas, especially in the capital Kuala Lumpur and surrounding region. However, in other regions, vulnerability to dengue varied throughout the year due to the influence of seasonal climate conditions, such as monsoon patterns. The WADI tool complements early warning models for water-associated disease by providing upstream information for planning prevention and control approaches, which increasingly require a comprehensive and geographically broad understanding of vulnerability for implementation. [ABSTRACT FROM AUTHOR]

Increasing demand for global food production is leading to greater use of irrigation to supplement rainfall and enable more intensive use of land. Minimizing adverse impacts of this intensification on surface water and groundwater resources is of critical importance for the achievement of sustainable land use. In this paper we examine the linkages between irrigation runoff and resulting changes in quality of receiving surface waters and groundwaters in Australia and New Zealand. Case studies are used to illustrate impacts under different irrigation techniques (notably flood and sprinkler systems) and land uses, particularly where irrigation has led to intensification of land use. For flood irrigation, changes in surface water contaminant concentrations are directly influenced by the amount of runoff, and the intensity and kind of land use. Mitigation for flood irrigation is best achieved by optimizing irrigation efficiency. For sprinkler irrigation, leaching to groundwater is the main transport path for contaminants, notably nitrate. Mitigation measures for sprinkler irrigation should take into account irrigation efficiency and the proximity of intensive land uses to sensitive waters. Relating contaminant concentrations in receiving groundwaters to their dominant causes is often complicated by uncertainty about the subsurface flow paths and the possible pollutant sources, viz. drainage from irrigated land. This highlights the need for identification of the patterns and dynamics of surface and subsurface waters to identify such sources of contaminants and minimize their impacts on the receiving environments. [ABSTRACT FROM AUTHOR]

Marine organisms comprising animals and plants are wealthiest sources of bioactive compounds possessing various pharmacological properties specifically: free radical scavenging, antitumor, antimicrobial, analgesic, neuroprotective and immunomodulatory. Marine drugs provide an alternative source to meet the demand of effective, safe and low-cost drugs that are rising with the continuously growing world population. Cancer is one of the leading reasons of mortality in western nations in contrast to communicable diseases of developing nations. In spite of outstanding developments in cancer therapy in past three decades, there is still an insistent necessity for innovative drugs in the area of cancer biology, especially in the unexplored area of marine anticancer compounds. However, recent technological innovations in structure revelation, synthetic creation of new compounds and biological assays have made possible the isolation and clinical assessment of innumerable unique anticancer compounds from marine environment. This review provides an insight into the anticancer research so far conducted in the area of the marine natural products/synthetic derivatives, their possible molecular targets and the current challenges in the drug development. [ABSTRACT FROM AUTHOR]

Namibia has experienced challenges in the provision of drinking water to its population. A combination of various solutions should be explored to provide drinking water to the population. In this study, a combination of the raw water treatment with the Grifaid® filters and the compliance monitoring of microbial quality using the hydrogensulphide test kit was tested in two villages in Northern Namibia and one informal settlement in central Windhoek. The efficiency of treatment by site operators was limited as 100 % of samples taken at two of the sampling sites were positive for faecal contamination. Only at the Windhoek sampling site was the treatment of raw water by site operators partially successful, as 67 % of the treated water samples taken were negative for faecal contamination. Concentrations of faecal coliforms in the control samples ranged from below 0 to 6 CFUs/100 mL, with the correspondence rates with the H2S kit test ranging from 20 to 80 %. Recontamination of the water after treatment is the most likely cause of the positive signal in the H2S kit. The site operators found the Grifaid® filters easy to use, but stressed that proper training is required for operating the filters. The users stated that the use of the Grifaid® filters are only suitable as a short-term solution in drinking water provision to the target communities. Future research will have to focus on the testing of the chemical and physical characteristics of raw and treated water; and more detailed examination of the microbial composition of the water samples will have to be conducted. In addition, the citizen-science strategy will have to be modified to assist the community in preventing recontamination of the treated water. [ABSTRACT FROM AUTHOR]

Water system degradation has a severe impact on daily life, especially in developing countries. However, microbial changes associated with this degradation, especially changes in microbes related to sulfur (S) cycling, are poorly understood. In this study, the abundance, structure, and diversity of sulfate-reducing microorganisms (SRM) and sulfur-oxidizing microorganisms (SOM) in the sediments from the Ziya River Basin, which is polluted by various human interventions (urban and agricultural activities), were investigated. Quantitative real-time PCR showed that the S cycling-related (SCR) genes (dsrB and soxB) were significantly elevated, reaching 2.60 × 107 and 1.81 × 108 copies per gram of dry sediment, respectively, in the region polluted by human urban activities (RU), and the ratio of dsrB to soxB abundance was significantly elevated in the region polluted by human agricultural activities (RA) compared with those in the protected wildlife reserve (RP), indicating that the mechanisms underlying water system degradation differ between RU and RA. Based on a 16S rRNA gene analysis, human interventions had substantial effects on microbial communities, particularly for microbes involved in S cycling. Some SCR genera (i.e., Desulfatiglans and Geothermobacter) were enriched in the sediments from both RA and RU, while others (i.e., Desulfofustis and Desulfonatronobacter) were only enriched in the sediments from RA. A redundancy analysis indicated that NH4+-N and total organic carbon significantly influenced the abundance of SRM and SOM, and sulfate significantly influenced only the abundance of SRM. A network analysis showed high correlation between SCR microorganisms and other microbial groups for both RU and RA, including those involved in carbon and metal cycling. These findings indicated the different effects of different human interventions on the microbial community composition and water quality degradation. [ABSTRACT FROM AUTHOR]

Microfluidic channels filled with spatially periodic arrays of impermeable obstacles have been proved successful for the size-based continuous separation of mesoscopic objects suspended in a buffer solution with unprecedented resolution. To date however, this technique - referred to as Deterministic Lateral Displacement (DLD) - has been implemented only for small volume samples, mainly for analytical purposes. In this article, we investigate the feasibility of the DLD separation technique for water purification from bacteria. The accurate numerical solution of the three-dimensional Stokes flow problem is used to establish the hydraulic resistance of several different geometries of the unit periodic cell. Results suggest that DLD-based microfilters resulting from numbering-up DLD microseparation units could provide sizeable flowrates and could prove competitive when compared to membrane-based modules. [ABSTRACT FROM AUTHOR]

Here we provide seasonal data on the concentrations of total coliform, Escherichia coli and Enterococcus spp. and six opportunistic pathogens (Acanthamoeba spp., Legionella spp., Legionella pneumophila, Mycobacterium avium, Mycobacterium intracellulare, and Pseudomonas aeruginosa) of public health significance in 24 tank water samples over six monthly sampling events from August 2015 to March 2006. Quantitative PCR (qPCR) assays were chosen for the quantification of six opportunistic pathogens and culture-based methods were used for the enumeration of fecal indicators. The data fle has been stored in a publicly available repository. The data on concentrations of opportunistic pathogens in RHRW will provide information for rainwater users regarding potential seasonality of risks. Quantitative data presented in this study can be used to perform quantitative microbial risk assessment (QMRA) of RHRW for various potable and nonpotable uses. Data can be used by health regulators to develop guidelines related to RHRW. [ABSTRACT FROM AUTHOR]

Microbial risk was quantified to assess human health risk as a result of exposure to E. coli in reclaimed wastewater irrigation. Monitoring data on E. coli were collected from pond water in paddy rice plots during the growing season. Five treatments were used and each was triplicated to evaluate the changes in E. coli concentrations in experiments performed in 2003 and 2004. The Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion among farmers and neighboring children. A Monte Carlo simulation (10,000 trials) was conducted to estimate the risk associated with uncertainty. In this study, risk values ranged from 10−4 to 10−8. UV-disinfected irrigation water showed a lower risk value than others, and its level was within the range of the actual paddy rice field with surface water. Agricultural activity was thought to be safer after 1–2 days, when the paddy field was irrigated with reclaimed wastewater. Also, children were found to have a greater risk of infection with E. coli. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of wastewater reuse in paddy rice culture. [ABSTRACT FROM AUTHOR]

Genetic markers are expected to provide better specificity in epidemiological studies and potentially serve as better indicators of water-bome pathogens. Methods used to assess genetic markers of emerging microbial indicators include pulsed field gel electrophoresis, polymerase chain reaction (PCR), and microarrays. This paper outlines a high-throughput approach to screen for such genetic markers using a set of theoretical and experimental screening tools. The theoretical screening involves evaluating genes related to the ribosomal RNA and specific functions from emerging indicator groups, followed by experimental validation with appropriate sampling schemes and high-throughput and economical screening methods, such as microarrays, real time PCR, and on-chip PCR. Analysis of a wide range of samples covering temporal variability in location, host, and waterborne disease outbreaks is essential. The proposed approach is expected to shorten the time and cost associated with searching for new genetic markers of emerging indicators by at least 10-fold. [ABSTRACT FROM AUTHOR]

The paper presents a new index for assessing water trophy and organic pollution. It is based on only true aquatic macrophytes – being calculated on species score, coefficient of ecological amplitude and degree of cover. The method was tested in an acidic lowland river and an alkaline mountain river, and is shown to be validated by bio-indication scales based on macrophyte communities. The practical interest is discussed regarding the Water Framework Directive. [ABSTRACT FROM AUTHOR]

The present paper reports the results on the occurrence and composition of steady state phytoplankton assemblages in the shallow water bodies of 18 Bulgarian natural wetlands. They all differ in their morphometry, hydrology and trophic state. Steady states were identified according to Sommer & Padisák (1993) when (i) 1, 2 or 3 species of algae contribute more than 80% of total biomass, (ii) their existence or coexistence persists for long enough (more than 1–2 weeks) and (iii) during that period the total biomass does not increase significantly. These situations were rare and were dominated by 7 stress-tolerant, colony-forming and ruderal disturbance-tolerant cyanoprokaryotes ( Microcystis aeruginosa, Microcystis wesenbergii, Anabaena spiroides, Anabaenopsis arnoldii, Aphanizomenon flos-aquae, Aphanizomenon gracile and Cylindrospermopsis raciborskii). The equilibrium states had been registered only during hypertrophic conditions in three stressed and frequently disturbed shallow water bodies and were related to the summer – late summer season. [ABSTRACT FROM AUTHOR]

An estimated 2300 people became seriously ill and 7 died from exposure to microbially contaminated drinking water in the town of Walkerton, Ontario, in May of 2000. The severity of this drinking water disaster resulted in the Government of Ontario calling a public inquiry by Mr. Justice Dennis O'Connor to address the cause of the outbreak, the role, if any, of government policies in contributing to this outbreak, and ultimately, the implications of this experience on the safety of drinking water across the province of Ontario. This paper summarizes relevant evidence presented at the inquiry by the expert panel together with Justice O'Connor's findings addressing the circumstances of the outbreak. These findings are reviewed in relation to the published causes of previous waterborne disease outbreaks that have been reported elsewhere in developed countries. The circumstances surrounding the Walkerton tragedy are an important source of knowledge for those concerned with providing safe drinking water to the public. Although some circumstances are obviously specific to this epidemic, others echo common themes in waterborne outbreaks that have occurred before. These common themes suggest the need for attention to broad issues of drinking water safety in addition to the individual specific details that often command attention. Key words: waterborne disease, Escherichia coli O157:H7, Campylobacter jejuni, Cryptosporidium, Giardia, multiple barriers, health risk.Environ 2300 personnes sont devenues gravement malades et sept personnes sont décédées à la suite d'une exposition à de l'eau potable contaminée par voie microbienne dans la ville de Walkerton, en Ontario, en mai 2000. La gravité de ce désastre d'eau potable a fait que le gouvernement de l'Ontario a lancé une enquête publique, menée par M. le juge Dennis O'Connor, visant à déterminer la cause de cette éclosion, la contribution, s'il y a en une, des politiques gouvernementales à cette éclosion et, en bout de ligne, les répercussions de cette expérience sur la salubrité de l'eau potable partout en Ontario. Cet article résume les preuves pertinentes présentées à l'enquête par le panel d'experts et les conclusions du juge O'Connor sur les circonstances de cette éclosion. Ces conclusions sont revues à la lumière des causes publiées touchant les éclosions antérieures de maladies hydriques qui ont été rapportées ailleurs dans les pays développés. Les circonstances entourant la tragédie de Walkerton sont une source importante de connaissances pour les compagnies fournissant de l'eau potable salubre au public. Bien que certaines circonstances sont évidemment spécifiques à cette épidémie, d'autres font penser à des thèmes communs aux éclosions hydriques survenues auparavant. Ces thèmes communs suggèrent le besoin de porter attention aux grandes questions de la sécurité de l'eau potable en plus des détails uniques spécifiques qui doivent souvent être examinés. Mots clés : maladie hydrique, Escherichia coli O157:H7, Campylobacter jejuni, Cryptosporidium, Giardia, barrières multiples, risque pour la santé. [Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Background: The seventh cholera pandemic has been ongoing in Mexico since 1991 and threatens to become endemic. This paper aims to determine the geographical pattern of cholera in Mexico to define areas at high risk of endemic cholera.Methods: Ecologic research was conducted based upon the cartography of disease incidence. The 32 Mexican states were grouped into five strata according to the value of the 1991-1996 cumulative incidence rate of cholera. Rate ratios were computed for strata of states classified by geographical situation, urbanization, and poverty level.Results: Cholera incidence was 2.47 times higher in coastal states than in the interior (95% CI : 2.42-2.52). The disease was negatively associated with urbanization. Incidence in the least urbanized stratum was four times as high as in the most urban stratum (95% CI : 3.9-4.12). The poorest stratum showed the most remarkable incidence, i.e. 5.9 times higher than the rate in the least poor stratum (95% CI : 5.73-6.04).Conclusions: This ecologic research suggests that high poverty level, low urbanization, and southern location are the most important predictors of endemic cholera in Mexican states. It is hypothesized that the natural environment of the coastal plains in southern states may also play a significant role in cholera incidence. Poor communities residing in the southern, predominantly rural, coastal states should be prioritized when it comes to investing in safe water supply facilities, adequate excreta disposal systems and cholera surveillance. [ABSTRACT FROM AUTHOR]

Disease due to waterborne pathogens, whether in outbreak or endemic form, continues to be a problem in both the developing and the developed world. Control of waterborne disease requires accurate assessment of the pathogen dose-response relation and of likely patterns of exposure. Heretofore, risk assessment of pathogen exposure has been done on the basis of several standard biologically plausible dose-response models. In this paper, the problem of estimating the long-term risk from waterborne pathogens is put into a rigorous mathematical and statistical framework. The implications of the biologic assumptions embedded in the dose-response models (e.g., heterogeneity in susceptibility) are fully considered, as are the likely patterns of long-term exposure (e.g., temporal correlations within individuals and heterogeneity of mean exposures). Two types of long-term risk are described, risk per person-time and risk per individual where the latter is the risk of infection at least once. The effects on these risks of heterogeneity in individuals’ susceptibilities and mean exposures and of temporal correlations of exposures are described, both theoretically and empirically using a sample of experimental data sets. Because different models with equal plausibility may give very different results in the low-dose range but fit the experimental data equally well, we apply the model uncertainty algorithm of Buckland et al. (1997) on example data sets. Finally, the computational aspects of the general problem, which are often challenging, are discussed along with the conditions under which simplifying approximations may be utilized. [ABSTRACT FROM AUTHOR]