The Experts below are selected from a list of 7956 Experts worldwide ranked by ideXlab platform
J A Ocio - One of the best experts on this subject based on the ideXlab platform.
-
presence of giardia cysts and Cryptosporidium Oocysts in drinking water supplies in northern spain
Journal of Applied Microbiology, 2007Co-Authors: David Carmena, X Aguinagalde, C Zigorraga, Juan C Fernandezcrespo, J A OcioAbstract:Aims: To evaluate the prevalence of Cryptosporidium and Giardia in surface water supplies from the province of Alava, northern Spain, and to investigate possible associations among the presence of these pathogenic protozoa with microbiological, physicochemical and atmospheric parameters. Methods and results: A total of 284 samples of drinking and recreational water supplies were analysed. Cryptosporidium Oocysts were found in 63AE5% of river samples, 33AE3% of reservoirs samples, 15AE4% and 22AE6% of raw water samples from conventional and small water treatment facilities (respectively), 30AE8% of treated water from small treatment facilities, and 26AE8% of tap water from municipalities with chlorination treatment only. Giardia cysts were found in 92AE3% of river samples, 55AE5% of reservoirs samples, 26AE9% and 45AE2% of raw water samples from conventional and small water treatment facilities (respect- ively), 19AE2% of treated water from small treatment facilities, and 26AE8% of tap water from municipalities with chlorination treatment only. The presence of Cryptosporidium and Giardia had significant Pearson's correlation coefficients (P <0 AE01) with the turbidity levels of the samples, and a number of significant associations were also found with the count levels for total coliforms and Escherichia coli. The samples were positive for Cryptosporidium significantly (P <0 AE05) more frequently during the autumn season than during the spring and winter seasons. No significant differences were found in the seasonal pat- tern of Giardia. A moderate association (r ¼ 0AE52) was found between rainfall and the presence of Cryptosporidium Oocysts. Conclusions: Cryptosporidium and Giardia are consistently found at elevated concentrations in surface waters for human consumption from the province of Alava, northern Spain. Significance and Impact of the Study: Water treatments based on rapid filtra- tion process and/or chlorination only are often unsatisfactory to provide safe drinking water, a situation that represents an important public health problem for the affected population because of the risk of waterborne outbreaks.
Tsuyoshi Hirata - One of the best experts on this subject based on the ideXlab platform.
-
Genotyping of single Cryptosporidium Oocysts isolated from sewage and river water.
Water Science and Technology, 2006Co-Authors: Tsuyoshi Hirata, A. HashimotoAbstract:The study was designed to genotype individual Cryptosporidium Oocysts using an 18S rRNA gene-based semi-nested PCR and direct sequencing procedure. Positive PCR amplification was observed in all single C. parvum HNJ-1 oocyst samples tested. Semi-nested PCR and direct sequencing was applied to Cryptosporidium Oocysts isolated from sewage and river water. The procedure could genotype 54% of FITC-stained single Oocysts isolated from sewage and 32% from river water. The predominant genotype in both sewage and river water was C. parvum genotype 1, accounting for 33 and 25%, respectively, of all the FITC-stained intact Cryptosporidium Oocysts present.
-
Genotyping of single Cryptosporidium Oocysts in sewage by semi-nested PCR and direct sequencing.
Water Research, 2006Co-Authors: Atsushi Hashimoto, Hitomi Sugimoto, Shigemitsu Morita, Tsuyoshi HirataAbstract:This study describes an approach for genotyping individual Cryptosporidium Oocysts obtained from sewage. We isolated single immunofluorescent assay (IFA)-stained Cryptosporidium Oocysts from sewage concentrate using glass capillary pipettes and inverted epifluorescence microscopy. Each isolated Cryptosporidium oocyst was analyzed by semi-nested PCR for the 18S rRNA gene and direct sequencing of the PCR products. A total of 74 of 107 Oocysts isolated from sewage were genotyped successfully. Of the 74 genotyped isolates, 51% (38 Oocysts) were identified as C. parvum genotype 1, 4% (3 Oocysts) of C. parvum VF383 human isolates, 20% (15 Oocysts) of C. parvum genotype 2, 14% (10 Oocysts) of C. meleagridis, 7% (5 Oocysts) of C. sp. Pig 1, 3% (2 Oocysts) of C. sp PG1-26 pig isolates and 1% (1 oocyst) of C. parvum CPM1 isolated from mouse. The results of this study demonstrate that 18S rRNA-based semi-nested PCR and direct sequencing can be used to characterize individual Cryptosporidium Oocysts and also to reveal the distribution of Cryptosporidium genotypes in environmental waters.
-
Prevalence of Cryptosporidium Oocysts and giardia cysts in the drinking water supply in Japan.
Water Research, 2002Co-Authors: Atsushi Hashimoto, S. Kunikane, Tsuyoshi HirataAbstract:Abstract A one-year monitoring of Cryptosporidium Oocysts and Giardia cysts was conducted at a water purification plant. A total of 13 samples of 50 L river source water and 26 samples of 2000 L-filtered water, treated by coagulation–flocculation, sedimentation and rapid filtration, were tested. Prior to conducting a survey of a water purification plant, we developed a method for concentrating Cryptosporidium Oocysts from a large volume of raw or filtered water using a hollow fiber ultrafiltration (UF) membrane, and this procedure was adapted to survey a water purification plant. Cryptosporidium Oocysts were detected in all of the 13 raw water samples. The geometric mean concentration was 40 Oocysts/100 L. Giardia cysts were detected in 12 of 13 raw water samples (92%) and the geometric mean concentration was 17 cysts/100 L. Probability distributions of both Cryptosporidium oocyst and Giardia cyst concentration in raw water were nearly lognormal. In filtered water samples, Cryptosporidium Oocysts were detected in 9 of the 26 samples (35%) with the geometric mean concentration of 1.2 Oocysts/1000 L and Giardia cysts in 3 samples (12%) with 0.8 cysts/1000 L. The estimated log 10 removal efficiency of Cryptosporidium Oocysts and Giardia cysts by rapid-sand filtration was 2.47 and 2.53, respectively. Empty particles were removed at a higher log 10 than intact Oocysts and cysts. The efficiency of particle removal in the rapid sand filtration process tends to be reduced under cold-water conditions. Close management is necessary in the winter when the water temperature is low.
-
Occurrence of Cryptosporidium Oocysts and Giardia cysts in a conventional water purification plant.
Water Science and Technology, 2001Co-Authors: A. Hashimoto, Tsuyoshi Hirata, S. KunikaneAbstract:A one-year monitoring of Cryptosporidium Oocysts and Giardia cysts was conducted at a water purification plant. A total of thirteen 50 L samples of river source water and twenty-six 2,000 L samples of filtered water (treated by coagulation-flocculation, sedimentation and rapid filtration) were concentrated using a hollow fibre ultrafiltration membrane module at a purification plant. Cryptosporidium Oocysts were detected in all raw water samples with a geometric mean concentration of 400 Oocysts/m3 (range 160-1,500 Oocysts/m3). Giardia cysts were detected in 12/13 raw waters (92%) with a geometric mean concentration of 170 cysts/m3 (range 40-580 Oocysts/m3). Probability distributions of both Cryptosporidium oocyst and Giardia cyst concentration in raw water were nearly log-normal. In filtered water samples, Cryptosporidium Oocysts were detected in 9/26 samples (35%) with a geometric mean concentration of 1.2 Oocysts/m3 (range 0.5-8 Oocysts/m3) and Giardia cysts in three samples (12%) with 0.8 cysts/m3 (range 0.5-2 Oocysts/m3). The estimated removal of Cryptosporidium Oocysts and Giardia cysts was, respectively, 2.54 log10 and 2.53 log10 on the basis of geometric means, 3.20 and 3.57 log10 on the basis of 50% observation level and 2.70 and 2.90 log10 on the basis of 90% observation level.
C R Fricker - One of the best experts on this subject based on the ideXlab platform.
-
routine monitoring of Cryptosporidium Oocysts in water using flow cytometry
Journal of Applied Microbiology, 1993Co-Authors: G Vesey, J S Slade, M Byrne, K Shepherd, P J Dennis, C R FrickerAbstract:A flow cytometric method for the routine analysis of environmental water samples for the presence of Cryptosporidium Oocysts has been developed. It uses a Coulter Epics Elite flow cytometer to examine water samples and to separate Oocysts from contaminating debris by cell sorting. The sorted particles are then rapidly screened by microscopy. The method has been evaluated and compared with direct epifluorescence microscopy on 325 river, reservoir and drinking water samples. The technique was found to be more sensitive, faster and easier to perform than conventional epifluorescent microscopy for the routine examination of water samples for Cryptosporidium.
-
A new method for the concentration of Cryptosporidium Oocysts from water.
Journal of Applied Microbiology, 1993Co-Authors: G Vesey, J S Slade, M Byrne, K Shepherd, C R FrickerAbstract:A novel method for the concentration of Cryptosporidium Oocysts from water has been developed, based upon the precipitation of calcium carbonate. A 10 1 water sample is treated by adding solutions of calcium chloride and sodium bicarbonate and raising the pH value to 10 with sodium hydroxide. Crystals of calcium carbonate form and enmesh particles in the Cryptosporidium oocyst size range. The crystals are allowed to settle, the supernatant fluid is discarded and the calcium carbonate precipitate dissolved in sulphamic acid. The sample can be concentrated further by centrifugation. Recoveries of Oocysts from seeded samples of deionized, tap and river water were in excess of 68%.
David Carmena - One of the best experts on this subject based on the ideXlab platform.
-
presence of giardia cysts and Cryptosporidium Oocysts in drinking water supplies in northern spain
Journal of Applied Microbiology, 2007Co-Authors: David Carmena, X Aguinagalde, C Zigorraga, Juan C Fernandezcrespo, J A OcioAbstract:Aims: To evaluate the prevalence of Cryptosporidium and Giardia in surface water supplies from the province of Alava, northern Spain, and to investigate possible associations among the presence of these pathogenic protozoa with microbiological, physicochemical and atmospheric parameters. Methods and results: A total of 284 samples of drinking and recreational water supplies were analysed. Cryptosporidium Oocysts were found in 63AE5% of river samples, 33AE3% of reservoirs samples, 15AE4% and 22AE6% of raw water samples from conventional and small water treatment facilities (respectively), 30AE8% of treated water from small treatment facilities, and 26AE8% of tap water from municipalities with chlorination treatment only. Giardia cysts were found in 92AE3% of river samples, 55AE5% of reservoirs samples, 26AE9% and 45AE2% of raw water samples from conventional and small water treatment facilities (respect- ively), 19AE2% of treated water from small treatment facilities, and 26AE8% of tap water from municipalities with chlorination treatment only. The presence of Cryptosporidium and Giardia had significant Pearson's correlation coefficients (P <0 AE01) with the turbidity levels of the samples, and a number of significant associations were also found with the count levels for total coliforms and Escherichia coli. The samples were positive for Cryptosporidium significantly (P <0 AE05) more frequently during the autumn season than during the spring and winter seasons. No significant differences were found in the seasonal pat- tern of Giardia. A moderate association (r ¼ 0AE52) was found between rainfall and the presence of Cryptosporidium Oocysts. Conclusions: Cryptosporidium and Giardia are consistently found at elevated concentrations in surface waters for human consumption from the province of Alava, northern Spain. Significance and Impact of the Study: Water treatments based on rapid filtra- tion process and/or chlorination only are often unsatisfactory to provide safe drinking water, a situation that represents an important public health problem for the affected population because of the risk of waterborne outbreaks.
Jennifer L. Clancy - One of the best experts on this subject based on the ideXlab platform.
-
Occurrence of Cryptosporidium Oocysts in US wastewaters.
Journal of Water and Health, 2006Co-Authors: Randi M. Mccuin, Jennifer L. ClancyAbstract:Wastewater samples collected from ten wastewater facilities across the US were analyzed to determine the occurrence of indigenous Cryptosporidium Oocysts using methods based on modifications of USEPA Method 1622. Wastewater facilities participating in this study ranged in size from 0.6 to 193mgd average daily flow. A total of 289 wastewater samples were analyzed over a 15-month period. ColorSeed is a commercial product containing gamma-irradiated Cryptosporidium Oocysts that have been permanently stained with a Texas Red dye. ColorSeed was used as an internal control with each sample to assess method performance. In 500ml sample volumes, mean ColorSeed recoveries in raw influents and primary effluents were 26.1^17.7% and 33.0 ^ 17.9%, respectively. In 10 liter volumes of secondary effluent, mean ColorSeed recovery was 25.0 ^ 16.6%. Volumes analyzed for tertiary effluent samples ranged from 14.8l to 131.3l resulting in a mean ColorSeed recovery of 48.8 ^ 14.5%. Indigenous Oocysts were detected in 30% of raw influents, 46% of primary effluents, 58% of secondary effluents and 19% of tertiary effluents analyzed. Indigenous oocyst concentrations ranged from ,2 to 86 /liter across all wastewater matrices tested.
-
Methods for the recovery, isolation and detection of Cryptosporidium Oocysts in wastewaters.
Journal of Microbiological Methods, 2005Co-Authors: Randi M. Mccuin, Jennifer L. ClancyAbstract:This correspondence describes the successful development of methods for the recovery, isolation and detection of Cryptosporidium Oocysts in wastewater and biosolids. Wastewater from one plant was used to optimize methods in raw influent as well as primary, secondary and tertiary effluents. Raw influents and primary effluents were concentrated using centrifugation followed by isolation of Cryptosporidium Oocysts using immunomagnetic separation (IMS) and detection of recovered organisms using epifluorescence microscopy. Mean oocyst recovery in raw influent was 29.2+/-12.8% and 38.8+/-27.9% in primary effluent at three sample volumes tested. Secondary and tertiary effluents were analyzed using a modified Method 1622 resulting in mean oocyst recoveries of 53.0+/-19.2% and 67.8+/-4.4%, respectively. In biosolids with approximately 10% total solids, mean oocyst recovery was 43.9+/-10.1% using IMS with a 5 g (wet weight) sample size. Due to the variability in these matrices, an internal microbiological standard was incorporated to serve as a tool for method performance.
-
Recovery of Cryptosporidium Oocysts and Giardia cysts from source water concentrates using immunomagnetic separation.
Journal of Microbiological Methods, 2001Co-Authors: Randi M. Mccuin, Zia Bukhari, Jose A. H. Sobrinho, Jennifer L. ClancyAbstract:Abstract Immunomagnetic separation (IMS) procedures for the simultaneous isolation of Cryptosporidium Oocysts and Giardia cysts have recently become available. We validated Dynal's GC-Combo IMS kit using source water at three turbidity levels (5000, 500 and 50 nephelometric turbidity units [ntu]) obtained from different geographical locations and spiked with approximately 9–11 (oo)cysts per ml. Mean recoveries of Cryptosporidium Oocysts and Giardia cysts in deionized water were 62% and 69%, respectively. In turbid water matrices, mean recoveries of Cryptosporidium Oocysts were between 55.9% and 83.1% while mean recoveries of cysts were between 61.1% and 89.6%. Marginally higher recoveries of the heat inactivated (oo)cysts were observed (119.4% Cryptosporidium Oocysts and 90.9% Giardia cysts) in deionized water when compared with recoveries of viable (oo)cysts (69.7% Cryptosporidium Oocysts and 79% Giardia cysts). Age of (oo)cysts on recoveries using the GC-Combo IMS kit demonstrated no effects up to 20 months old. Recovery of Giardia cysts was consistent for isolates aged up to 8 months (81.4%), however, a significant reduction in recoveries was noted at 20 months age. Recoveries of low levels (5 and 10 (oo)cysts) of Cryptosporidium Oocysts and Giardia cysts in deionized water using IMS ranged from 51.3% to 78% and from 47.6% to 90.0%, respectively. Results of this study indicate that Dynal's GC-Combo IMS kit is an efficient technique to separate Cryptosporidium / Giardia from turbid matrices and yields consistent, reproducible recoveries. The use of fresh (recently voided and purified) (oo)cysts, aged (oo)cysts, viable and heat-inactivated (oo)cysts indicated that these parameters do not influence IMS performance.
-
UV light inactivation of Cryptosporidium Oocysts
Journal American Water Works Association, 1998Co-Authors: Jennifer L. Clancy, Marilyn M. Marshall, Thomas M. Hargy, John E. DyksenAbstract:Cryptosporidium parvum Oocysts are highly resistant to conventional chlorine-based disinfectants. The authors tested two innovative electrotechnologies that use ultraviolet (UV) light and found that both pulsed UV and advanced UV inactivated Cryptosporidium Oocysts. The advanced UV system achieved >4-log inactivation as determined in animal infectivity studies using the neonatal mouse model. With the pulsed UV system, oocyst inactivation was also noted in the process control (non-UV-exposed Oocysts), suggesting that some oocyst inactivation may have occurred independently of UV exposure. Irrespective of this, both technologies appear to be effective and novel ways to treat drinking water and to provide an additional significant barrier that helps protect public health.