Publications by authors named "Mark O"

13 Publications

  • Page 1 of 1

Combined Immunofluorescence (IFA) and Fluorescence In Situ Hybridization (FISH) Assays for Diagnosing Babesiosis in Patients from the USA, Europe and Australia.

Diagnostics (Basel) 2020 Sep 28;10(10). Epub 2020 Sep 28.

ID-FISH Technology Inc., Milpitas, CA 95035, USA.

Apicomplexan parasites of the genus cause babesiosis in humans and animals worldwide. Human babesiosis is a predominantly zoonotic disease transmitted by hard ticks that is of increasing health concern in the USA and many other countries. Microscopic examination of stained blood smears, detection of serum antibodies by immunoassays and identification of parasite nucleic acid in blood by qPCR and fluorescence in situ hybridization (FISH) are some methods available for diagnosing babesiosis. This study investigated the use of a genus-specific FISH test for detecting parasites in blood smears and immunofluorescence assay (IFA) for detecting serum antibodies to and , two common species that cause human babesiosis in the USA. The findings with clinical samples originating from USA, Australia, Europe and elsewhere demonstrate that the parallel use of genus-specific FISH and IFA tests for and provides more useful diagnostic information in babesiosis and that infections are more widespread globally than presently recognized.
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http://dx.doi.org/10.3390/diagnostics10100761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7650773PMC
September 2020

A Fluorescence in Situ Hybridization (FISH) Test for Diagnosing Babesiosis.

Diagnostics (Basel) 2020 Jun 6;10(6). Epub 2020 Jun 6.

ID-FISH Technology Inc., 556 Gibraltar Drive, Milpitas, CA 95035, USA.

Apicomplexan parasites of the genus cause babesiosis in humans and animals. The microscopic examination of stained blood smears, detection of serum antibodies by immunoassays, and PCR-based identification of parasite nucleic acid in blood are common laboratory methods for diagnosing babesiosis. The present study evaluated a commercially available genus-specific fluorescence in situ hybridization (FISH) test for detecting parasites in blood smears. The FISH test detected and two common species that cause human infections in the USA, and other species of human and veterinary importance in less than two hours. The genus-specific FISH test supplements other existing laboratory methods for diagnosing babesiosis and may be particularly useful in resource-limited laboratories.
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http://dx.doi.org/10.3390/diagnostics10060377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7344499PMC
June 2020

Making the ecosystem services approach operational: A case study application to the Aarhus River, Denmark.

Sci Total Environ 2020 Mar 2;707:135836. Epub 2019 Dec 2.

University of Duisburg-Essen, Faculty of Biology, Aquatic Ecology, Universitätsstrasse 5, 45141 Essen, Germany; University of Duisburg-Essen, Centre for Water and Environmental Research, Universitätsstrasse 5, 45141 Essen, Germany. Electronic address:

The ecosystem services (ESS) approach seeks to identify and characterize links between ecosystems and human welfare. The DESSIN ESS evaluation framework is a novel methodology that has been developed to operationalize ecosystem service assessment, with a focus on urban freshwater settings. This paper describes an application of the framework to a retrospective case study in Aarhus, Denmark, which was used to test the framework and make suggestions for improvement. River restoration and wastewater management measures enhanced ecosystem state and the provision and use of purification and recreation ESS for selected beneficiaries, including increased economic values. Feedback from this case study suggests a missing link between science-based ESS approaches, which often have a normative basis in ecosystem status, and the real-world provision and use of ESS in urban settings. In the urban context, many ESS result from a combination of human and ecosystem inputs, and the human inputs can often be significant. Quantifying ESS provision and use therefore requires understanding how ecosystem and human inputs work together to make contributions to human welfare.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135836DOI Listing
March 2020

A dual colour fluorescence in situ hybridization (FISH) assay for identifying the zoonotic malaria parasite Plasmodium knowlesi with a potential application for the specific diagnosis of knowlesi malaria in peripheral-level laboratories of Southeast Asia.

Parasit Vectors 2017 Jul 19;10(1):342. Epub 2017 Jul 19.

ID-FISH Technology, Palo Alto, CA, USA.

Background: Plasmodium knowlesi is primarily responsible for zoonotic malaria in several Southeast Asian countries. Precise identification of the parasite in the blood of patients presently relies on an expensive and elaborate PCR procedure because microscopic examination of blood and other available field identification techniques lack adequate specificity. Therefore, the use of a simple and inexpensive dual-colour fluorescence in situ hybridization (FISH) assay, analogous to FISH assays recently described for Plasmodium falciparum and Plasmodium vivax, was investigated as a potential tool for identifying P. knowlesi.

Results: A P. knowlesi 18S rDNA sequence-based DNA probe was used to test thin blood smears of P. knowlesi by FISH, and fluorescence viewed in a light microscope fitted with a light emitting diode light source and appropriate emission and barrier filters. The limit of detection in the P. knowlesi FISH assay was 84 parasites per μl in infected monkey blood and 61 parasites per μl for P. knowlesi cultured in human blood. The P. knowlesi-specific FISH probe detected only P. knowlesi and not P. falciparum, Plasmodium malariae, Plasmodium ovale, P. vivax or a panel of other human blood-borne pathogens. A previously described Plasmodium genus-specific probe used simultaneously in the P. knowlesi FISH assay reacted with all tested Plasmodium species.

Conclusions: To our knowledge, this is the first description of a FISH assay for P. knowlesi that is potentially useful for diagnosing infections in remote laboratories in endemic countries.
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http://dx.doi.org/10.1186/s13071-017-2273-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5517825PMC
July 2017

Fluorescence In Situ Hybridization (FISH) Assays for Diagnosing Malaria in Endemic Areas.

PLoS One 2015 2;10(9):e0136726. Epub 2015 Sep 2.

ID-FISH Technology Inc., Palo Alto, California, United States of America; IGeneX Inc. Palo Alto, California, United States of America.

Malaria is a responsible for approximately 600 thousand deaths worldwide every year. Appropriate and timely treatment of malaria can prevent deaths but is dependent on accurate and rapid diagnosis of the infection. Currently, microscopic examination of the Giemsa stained blood smears is the method of choice for diagnosing malaria. Although it has limited sensitivity and specificity in field conditions, it still remains the gold standard for the diagnosis of malaria. Here, we report the development of a fluorescence in situ hybridization (FISH) based method for detecting malaria infection in blood smears and describe the use of an LED light source that makes the method suitable for use in resource-limited malaria endemic countries. The Plasmodium Genus (P-Genus) FISH assay has a Plasmodium genus specific probe that detects all five species of Plasmodium known to cause the disease in humans. The P. falciparum (PF) FISH assay and P. vivax (PV) FISH assay detect and differentiate between P. falciparum and P. vivax respectively from other Plasmodium species. The FISH assays are more sensitive than Giemsa. The sensitivities of P-Genus, PF and PV FISH assays were found to be 98.2%, 94.5% and 98.3%, respectively compared to 89.9%, 83.3% and 87.9% for the detection of Plasmodium, P. falciparum and P. vivax by Giemsa staining respectively.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136726PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4558036PMC
May 2016

Modelling the impact of retention-detention units on sewer surcharge and peak and annual runoff reduction.

Water Sci Technol 2015 ;71(6):898-903

Technical University of Denmark, Department of Environmental Engineering, Miljøvej, bygning 113, 2800 Kgs. Lyngby, Denmark E-mail:

Stormwater management using water sensitive urban design is expected to be part of future drainage systems. This paper aims to model the combination of local retention units, such as soakaways, with subsurface detention units. Soakaways are employed to reduce (by storage and infiltration) peak and volume stormwater runoff; however, large retention volumes are required for a significant peak reduction. Peak runoff can therefore be handled by combining detention units with soakaways. This paper models the impact of retrofitting retention-detention units for an existing urbanized catchment in Denmark. The impact of retrofitting a retention-detention unit of 3.3 m³/100 m² (volume/impervious area) was simulated for a small catchment in Copenhagen using MIKE URBAN. The retention-detention unit was shown to prevent flooding from the sewer for a 10-year rainfall event. Statistical analysis of continuous simulations covering 22 years showed that annual stormwater runoff was reduced by 68-87%, and that the retention volume was on average 53% full at the beginning of rain events. The effect of different retention-detention volume combinations was simulated, and results showed that allocating 20-40% of a soakaway volume to detention would significantly increase peak runoff reduction with a small reduction in the annual runoff.
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http://dx.doi.org/10.2166/wst.2015.044DOI Listing
October 2015

Effects of a 20 year rain event: a quantitative microbial risk assessment of a case of contaminated bathing water in Copenhagen, Denmark.

J Water Health 2013 Dec;11(4):636-46

Department of Environmental Engineering, Technical University of Denmark (DTU), Miljoevej, Building 113, 2800 Kgs. Lyngby, Denmark E-mail:

Quantitative microbial risk assessments (QMRAs) often lack data on water quality leading to great uncertainty in the QMRA because of the many assumptions. The quantity of waste water contamination was estimated and included in a QMRA on an extreme rain event leading to combined sewer overflow (CSO) to bathing water where an ironman competition later took place. Two dynamic models, (1) a drainage model and (2) a 3D hydrodynamic model, estimated the dilution of waste water from source to recipient. The drainage model estimated that 2.6% of waste water was left in the system before CSO and the hydrodynamic model estimated that 4.8% of the recipient bathing water came from the CSO, so on average there was 0.13% of waste water in the bathing water during the ironman competition. The total estimated incidence rate from a conservative estimate of the pathogenic load of five reference pathogens was 42%, comparable to 55% in an epidemiological study of the case. The combination of applying dynamic models and exposure data led to an improved QMRA that included an estimate of the dilution factor. This approach has not been described previously.
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http://dx.doi.org/10.2166/wh.2013.210DOI Listing
December 2013

Integration of research advances in modelling and monitoring in support of WFD river basin management planning in the context of climate change.

Sci Total Environ 2012 Dec 7;440:167-77. Epub 2012 Sep 7.

Vrije Universiteit Brussel (VUB), Dept. Hydrology and Hydrological Engineering, IUPWARE, Pleinlaan 2, B-1080 Brussels, Belgium.

The integration of scientific knowledge about possible climate change impacts on water resources has a direct implication on the way water policies are being implemented and evolving. This is particularly true regarding various technical steps embedded into the EU Water Framework Directive river basin management planning, such as risk characterisation, monitoring, design and implementation of action programmes and evaluation of the "good status" objective achievements (in 2015). The need to incorporate climate change considerations into the implementation of EU water policy is currently discussed with a wide range of experts and stakeholders at EU level. Research trends are also on-going, striving to support policy developments and examining how scientific findings and recommendations could be best taken on board by policy-makers and water managers within the forthcoming years. This paper provides a snapshot of policy discussions about climate change in the context of the WFD river basin management planning and specific advancements of related EU-funded research projects. Perspectives for strengthening links among the scientific and policy-making communities in this area are also highlighted.
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http://dx.doi.org/10.1016/j.scitotenv.2012.07.055DOI Listing
December 2012

Evaluation of two stormwater infiltration trenches in central Copenhagen after 15 years of operation.

Water Sci Technol 2011 ;63(10):2279-86

Department of Environmental Engineering, Technical University of Denmark, 2800 Lyngby, Denmark.

Two stormwater infiltration trenches were installed in 1993 in an area in central Copenhagen. The system was monitored continuously for almost three years after establishment, and a small reduction in performance over that time, possibly due to clogging, was noted. A new study was conducted in 2009 to see whether the reduction in performance has continued and to determine how the system performs today. Water levels in the trenches were monitored for almost 4 months, and from this period seven events were selected to analyse the infiltration rate. A comparison with similar analyses on storm sequences from the first 3 years of operation shows that the infiltration has decreased since the establishment of the system 15 years ago. The decrease is statistically significant (p<0.01). A clogging model was fitted to the data and predictions were made for future performance. The results show that the system will discharge around 10 times more annual overflow to the sewers after 100 years of operation compared to the initial volumes, if clogging continues at current rates. This corresponds to 60% of the total runoff from the area. The results show that clogging and proper maintenance are important factors to consider when implementing stormwater infiltration trenches.
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http://dx.doi.org/10.2166/wst.2011.158DOI Listing
November 2011

Flood analysis in mixed-urban areas reflecting interactions with the complete water cycle through coupled hydrologic-hydraulic modelling.

Water Sci Technol 2010 ;62(6):1386-92

DHI Water, Environment & Health, Agern Allé 5, Hørsholm 2970, Denmark.

The potential devastating effects of urban flooding have given high importance to thorough understanding and management of water movement within catchments, and computer modelling tools have found widespread use for this purpose. The state-of-the-art in urban flood modelling is the use of a coupled 1D pipe and 2D overland flow model to simultaneously represent pipe and surface flows. This method has been found to be accurate for highly paved areas, but inappropriate when land hydrology is important. The objectives of this study are to introduce a new urban flood modelling procedure that is able to reflect system interactions with hydrology, verify that the new procedure operates well, and underline the importance of considering the complete water cycle in urban flood analysis. A physically-based and distributed hydrological model was linked to a drainage network model for urban flood analysis, and the essential components and concepts used were described in this study. The procedure was then applied to a catchment previously modelled with the traditional 1D-2D procedure to determine if the new method performs similarly well. Then, results from applying the new method in a mixed-urban area were analyzed to determine how important hydrologic contributions are to flooding in the area.
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http://dx.doi.org/10.2166/wst.2010.365DOI Listing
December 2010

Dynamic modelling of pollutants from CSOs.

Authors:
F Schlütter O Mark

Water Sci Technol 2003 ;47(4):149-56

DHI-Water & Environment, Agern Allé 11 DK 2970 Hersholm, Denmark.

In a number of industrialised countries there is an effort made to reduce pollutant discharges from combined sewer overflows. After establishing proper treatment plants the CSO discharges are contributing with a higher percentage of the total pollutant load on the receiving waters. The acknowledgement of this issue has made the authorities in some countries issue requirements for maximum allowed pollutant loads and water quality from individual CSOs. However, in order to make standards for CSO emissions knowledge about the current state is needed and subsequently others needs to be able to document that they are in compliance with the standard. The question is how to calculate the annual pollutant load from a given CSO? The purpose of this article is to present results from calculation of annual loads in different ways.
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June 2003

Deterministic modelling of integrated urban drainage systems.

Water Sci Technol 2002 ;45(3):81-94

EAWAG, Dübendorf, Switzerland.

Today, the main concepts required for describing the dynamics of drainage in an entire urban area are known and models are available that can reasonably simulate the behaviour of the urban water system. Still, such integrated modelling is a complex exercise not only due to the sheer size of the model, but also due to the different modelling approaches that reflect the history of the sub-models used and of the purpose they were built for. The paper reviews the state of the art in deterministic modelling, outlines experiences and discusses problems and future developments.
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September 2002
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