Leo Heijnen

Leo Heijnen
KWR Water Research Institute · Water Quality & Health Research Group

About

49
Publications
9,929
Reads
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3,253
Citations
Citations since 2017
22 Research Items
1965 Citations
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20172018201920202021202220230200400600
20172018201920202021202220230200400600
Additional affiliations
February 2000 - present
KWR Water Research Institute
Position
  • Research Scientist: molecular microbiology

Publications

Publications (49)
Article
Full-text available
Over the course of the Corona Virus Disease-19 (COVID-19) pandemic in 2020–2022, monitoring of the severe acute respiratory syndrome coronavirus 2 ribonucleic acid (SARS-CoV-2 RNA) in wastewater has rapidly evolved into a supplementary surveillance instrument for public health. Short term trends (2 weeks) are used as a basis for policy and decision...
Preprint
Full-text available
Background Despite high vaccination rates in the Netherlands, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to circulate. Longitudinal sewage monitoring was implemented along with the notification of cases as two parts of the surveillance pyramid to validate the use of sewage surveillance for monitoring SARS-CoV-2, as an ea...
Article
For community-level monitoring, the European Commission under the EU Sewage Sentinel System recommends wastewater-based SARS-CoV-2 surveillance. Tracking SARS-CoV-2 variants in a community is pivotal for appropriate public health response. Genome sequencing of SARS-CoV-2 in wastewater samples for tracking variants is challenging, often resulting in...
Article
Full-text available
AOP decreases the number and concentration of OMP and chances of negative impact on ecology and groundwater quality. AOP decreased OMP concentrations in drinking water with no measurable negative effect on water quality parameters. MARR produces water with a highly stable chemical and microbiological composition and levels out seasonal peak fluctua...
Preprint
Over the course of the COVID-19 pandemic in 2020-2021, monitoring of SARS-CoV-2 RNA in wastewater has rapidly evolved into a supplementary surveillance instrument for public health. Short term trends (2 weeks) are used as a basis for policy and decision making on measures for dealing with the pandemic. Normalization is required to account for the v...
Article
Full-text available
Wastewater surveillance has shown to be a valuable and efficient tool to obtain information about the trends of COVID-19 in the community. Since the recent emergence of new variants, associated with increased transmissibility and/or antibody escape (variants of concern), there is an urgent need for methods that enable specific and timely detection...
Preprint
Full-text available
Wastewater based surveillance employing qPCR has already shown its utility for monitoring SARS-CoV-2 at community level, and consequently the European Commission has recommended the implementation of an EU Sewage Sentinel System. However, using sequencing for the determination of genomic variants in wastewater is not fully established yet. Therefor...
Article
Full-text available
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a major global health problem, and public health surveillance is crucial to monitor and prevent virus spread. Wastewater-based epidemiology has been proposed as an addition to disease-based surveillance because virus is shed in the feces of ≈40% of infected persons. We...
Preprint
Wastewater surveillance has shown to be a valuable and efficient tool to obtain information about the trends of COVID-19 in the community. Since the recent emergence of new variants, associated with increased transmissibility and/or antibody escape (variants of concern), there is an urgent need for methods that enable specific and timely detection...
Article
Analysing wastewater can be used to track infectious disease agents that are shed via stool and urine. Sewage surveillance of SARS-CoV-2 has been suggested as a tool to determine the extent of COVID-19 in cities and serve as an early warning for (re-)emergence of SARS-CoV-2 circulation in communities. The focus of this review is on the strength of...
Preprint
Full-text available
The current SARS-CoV-2 pandemic has rapidly become a major global health problem for which public health surveillance is crucial to monitor virus spread. Given the presence of viral RNA in feces in around 40% of infected persons, wastewater-based epidemiology has been proposed as an addition to disease-based surveillance to assess the spread of the...
Article
In the current COVID-19 pandemic, a significant proportion of cases shed SARS-Coronavirus-2 (SARS-CoV-2) with their faeces. To determine if SARS-CoV-2 RNA was present in sewage during the emergence of COVID-19 in the Netherlands, sewage samples of six cities and the airport were tested using four qRT-PCR assays, three targeting the nucleocapsid gen...
Article
Full-text available
In this study we investigate opportunities for reducing arsenic (As) to very low levels, below 1 μg/L in produced drinking water from artificially infiltrated groundwater. We observe that rapid sand filtration is the most important treatment step for the oxidation and removal of As at water treatment plants which use artificially recharged groundwa...
Preprint
In the current COVID-19 pandemic, a significant proportion of cases shed SARS-Coronavirus-2 (SARS-CoV-2) with their faeces. To determine if SARS-CoV-2 is present in sewage during the emergence of COVID-19 in the Netherlands, sewage samples of 7 cities and the airport were tested using RT-PCR against three fragments of the nucleocapsid protein gene...
Article
Full-text available
Background: A community-wide outbreak of Legionnaires' disease (LD) occurred in Genesee County, Michigan, in 2014 and 2015. Previous reports about the outbreak are conflicting and have associated the outbreak with a change of water source in the city of Flint and, alternatively, to a Flint hospital. Objective: The objective of this investigation...
Poster
Full-text available
In surface- and wastewater management it is important to determine the origin of the water and of the potentially problematic substances/organisms it might contain. These are faecal contamination, nutrient-related questions, or malfunctioning wastewater treatment plants (WWTPs). This research examines the possible contribution of the DNA fingerprin...
Article
Full-text available
Naturally present indigenous fresh water viruses are able to accurately monitor virus rejection of intact and damaged RO membranes, with high sensitivity and similar performance as spiked bacteriophage MS2.
Poster
Full-text available
The results of using Microbial Profiling (NGS on 16S rRNA amplicons) to detect fecal contaminations in drinking water are presented on this poster.
Article
Full-text available
Studies have shown that certain opportunistic pathogenic nontuberculous Mycobacterium (NTM) species can be present in distributed drinking water. However, detailed information about NTM population composition in drinking water is lacking. Therefore, NTM communities in unchlorinated drinking water from the distribution system of five treatment plant...
Article
Full-text available
The role of the water cycle in spreading human pathogenic influenza viruses is poorly studied and is not considered to be significant. However, gastrointestinal symptoms developed in a large proportion of influenza A (H1N1) 2009 virus infected people during the pandemic in 2009 and fecal shedding was reported. This fecal route could potentially pla...
Article
Full-text available
Watershed management to minimize introduction of pathogenic micro-organisms from fecal contaminants in the area lacks quantitative based decision-making. In this desk study a stochastic chainof-event model was developed and applied to quantify the microbial risk from Campylobacter in fecal material from grazing animals and noroviruses in fecal mate...
Article
Full-text available
Spores of sulphite-reducing clostridia (SSRC; incl. C. perfringens) have been introduced in water quality monitoring for microbial safety of drinking water because of their higher resistance to water disinfection processes than E. coli. Interpretation of this parameter, however, is hampered by lack of quantitative data on the spore decay rates. We...
Article
Full-text available
A rapid real-time NASBA method was developed for detection of Escherichia coli in water samples. In this method, a fragment of the clpB-mRNA is amplified and a specific molecular beacon probe is used to detect the amplified mRNA fragment during the NASBA reaction. The method was shown to be specific and sensitive (1 viable E. coli in 100ml) and can...
Article
Full-text available
Recent water related outbreaks of shiga toxin producing E. coli O157 have resulted in increased attention of the water industry to this potentially deadly pathogen. Current methods to detect E. coli O157 and its virulence genes are laborious and time-consuming. Specificity, sensitivity and simple use of a real-time PCR method makes it an attractive...
Article
The microbiological quality of drinking water from 144 private water supplies in the Netherlands was tested and additionally the occurrence of Escherichia coli O157 was examined. Faecal indicators were enumerated by using standard membrane filtration methods. The presence of E. coli O157 was determined using a specific enrichment method. Eleven per...
Article
A study was undertaken to compare the performance of five different molecular methods (available in four different laboratories) for the identification of Cryptosporidium parvum and Cryptosporidium hominis and the detection of genetic variation within each of these species. The same panel of oocyst DNA samples derived from faeces (n=54; coded blind...
Article
Arabidopsis thaliana has a relatively small genome of approximately 130 Mb containing about 10% repetitive DNA. Genome sequencing studies reveal a gene-rich genome, predicted to contain approximately 25 000 genes spaced on average every 4.5 kb. Between 10 to 20% of the predicted genes occur as clusters of related genes, indicating that local sequen...
Article
Full-text available
The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996, Here we report one of the first milestones of this project,...
Article
The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project,...
Article
Full-text available
The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project,...
Article
As part of the European Scientists Sequencing Arabidopsis program, a contiguous region (396607 bp) located on chromosome 4 around the APETALA2 gene was sequenced. Analysis of the sequence and comparison to public databases predicts 103 genes in this area, which represents a gene density of one gene per 3.85 kb. Almost half of the genes show no sign...
Article
As part of the European Scientists Sequencing Arabidopsis program, a contiguous region (396 607 bp) located on chromosome 4 around the APETALA2 gene was sequenced. Analysis of the sequence and comparison to public databases predicts 103 genes in this area, which represents a gene density of one gene per 3.85 kb. Almost half of the genes show no sig...
Article
The spike (S) protein of murine coronavirus strain A59 (MHV-A59) is a type I membrane protein that induces membrane fusion. In this study we have analyzed the role of two domains in the S protein on fusion. The 180-kDa mature S protein is partially cleaved into two 90-kDa subunits during transport to the plasma membrane. We have identified several...
Article
Mutations were introduced in the transmembrane region of the spike protein of the murine coronavirus A59. The maturation of these mutant S proteins was not affected, they were all expressed at the cell surface, and became acylated, however some mutant S proteins did not induce cell-to-cell fusion. An I-->K change in the middle of the predicted tran...
Article
We describe a novel strategy to site-specifically mutagenize the genome of an RNA virus by exploiting homologous RNA recombination between synthetic defective interfering (DI) RNA and the viral RNA. Marker mutations introduced in the DI RNA were replaced by the wild-type residues during replication. More importantly, however, these genetic markers...
Article
A new protein of the feline infectious peritonitis virus (FIPV) was discovered in lysates of infected cells. Expression of the gene encoding open reading frame (ORF) 6b of FIPV in recombinant vaccinia virus infected cells was used to identify it as the 6b protein. It is a novel type of viral glycoprotein whose function is not clear. It is a soluble...
Article
A new protein of feline infectious peritonitis coronavirus (FIPV) was discovered in lysates of [35S]cysteine-labeled infected cells. Expression of open reading frame (ORF) 6b of FIPV in recombinant vaccinia virus-infected cells was used to identify it as the 6b protein. Further characterization revealed that it is a novel type of viral glycoprotein...
Article
Full-text available
We describe a novel strategy to site-specifically mutagenize the genome of an RNA virus by exploiting homologous RNA recombination between synthetic defective interfering (Dl) RNA and the viral RNA. The construction of a full-length cDNA clone, pMIDI, of a Dl RNA of coronavirus MHV strain A59 was reported previously (R.G. Van der Most, P.J. Bredenb...
Article
A recombinant vaccinia virus producing the bacteriophage T7 RNA polymerase was used to express foreign genes in eukaryotic cells. Translation efficiency in this expression system was enhanced significantly by employing the encephalomyocarditis virus (EMCV) 5'-untranslated region (UTR) which confers cap-independent translation by directing internal...
Article
Full-text available
Coronavirus spike protein genes were expressed in vitro by using the recombinant vaccinia virus expression system. Recombinant spike proteins were expressed at the cell surface and induced cell fusion in a host-cell-dependent fashion. The intracellular transport of recombinant spike proteins was studied. The half time of acquisition of resistance t...
Article
One of the most interesting aspects of Coronavirus replication is their intracellular assembly. Budding is localized in the ER-pre Golgi region (8, 26). Both Coronavirus glycoproteins are synthesized in the RER on membrane bound ribosomes (16). The integral membrane protein (M) accumulates in the perinuclear region and is believed to determine the...

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