Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The effective design of sampling campaigns for emerging chemical and microbial contaminants in drinking water and its resources based on literature mining
    Hartmann, Julia ; Driezum, Inge van; Ohana, Dana ; Lynch, Gretta ; Berendsen, Bjorn ; Wuijts, Susanne ; Hoek, Jan Peter van der; Roda Husman, Ana Maria de - \ 2020
    Science of the Total Environment 742 (2020). - ISSN 0048-9697
    Contaminants - Early warning - Emerging - Pathogen

    As well as known contaminants, surface waters also contain an unknown variety of chemical and microbial contaminants which can pose a risk to humans if surface water is used for the production of drinking water. To protect human health proactively, and in a cost-efficient way, water authorities and drinking water companies need early warning systems. This study aimed to (1) assess the effectiveness of screening the scientific literature to direct sampling campaigns for early warning purposes, and (2) detect new aquatic contaminants of concern to public health in the Netherlands. By screening the scientific literature, six example contaminants (3 chemical and 3 microbial) were selected as potential aquatic contaminants of concern to the quality of Dutch drinking water. Stakeholders from the Dutch water sector and various information sources were consulted to identify the potential sources of these contaminants. Based on these potential contamination sources, two sampling sequences were set up from contamination sources (municipal and industrial wastewater treatment plants), via surface water used for the production of drinking water to treated drinking water. The chemical contaminants, mycophenolic acid, tetrabutylphosphonium compounds and Hexafluoropropylene Oxide Trimer Acid, were detected in low concentrations and were thus not expected to pose a risk to Dutch drinking water. Colistin resistant Escherichia coli was detected for the first time in Dutch wastewater not influenced by hospital wastewater, indicating circulation of bacteria resistant to this last-resort antibiotic in the open Dutch population. Four out of six contaminants were thus detected in surface or wastewater samples, which showed that screening the scientific literature to direct sampling campaigns for both microbial and chemical contaminants is effective for early warning purposes.

    Antibioticaresistente bacterien, resistentiegenen en antibiotica residuen in mest
    Schmitt, H. ; Blaak, H. ; Hoeksma, P. ; Schans, M.G.M. van de; Kemper, M. ; Rijk, S. de; Roda Husman, A.M. de - \ 2019
    Wageningen University & Research (RIVM briefrapport 2019-0112)
    Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage
    Hendriksen, Rene S. ; Munk, Patrick ; Njage, Patrick ; Bunnik, Bram Van; Mcnally, Luke ; Lukjancenko, Oksana ; Röder, Timo ; Nieuwenhuijse, David ; Pedersen, Susanne Karlsmose ; Kjeldgaard, Jette ; Kaas, Rolf S. ; Clausen, Philip Thomas Lanken Conradsen ; Vogt, Josef Korbinian ; Leekitcharoenphon, Pimlapas ; De Schans, Milou G.M. Van; Zuidema, Tina ; Roda Husman, Ana Maria De; Rasmussen, Simon ; Petersen, Bent ; Amid, Clara ; Cochrane, Guy ; Sicheritz-ponten, Thomas ; Schmitt, Heike ; Alvarez, Jorge Raul Matheu ; Aidara-kane, Awa ; Pamp, Sünje J. ; Lund, Ole ; Hald, Tine ; Woolhouse, Mark ; Koopmans, Marion P. ; Vigre, Håkan ; Petersen, Thomas Nordahl ; Aarestrup, Frank M. - \ 2019
    Nature Communications 10 (2019)1. - ISSN 2041-1723 - 12 p.
    Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use meta-genomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
    Molecular relatedness of ESBL/AmpC-producing Escherichia coli from humans, animals, food and the enviroment : a pooled analysis
    Dorado-Garcia, Alejandro ; Smid, J.H. ; Pelt, Wilfrid Van; Bonten, M.J.M. ; Fluit, A.C. ; Bunt, Gerrita van den; Wagenaar, J.A. ; Hordijk, J. ; Dierikx, C.M. ; Veldman, K.T. ; Koeijer, A.A. de; Dohmen, W. ; Schmitt, H. ; Liakopoulos, A. ; Pacholewicz, Ewa ; Lam, T.J.G.M. ; Velthuis, Annet ; Heuvelink, A. ; Gonggrijp, Maaike ; Duijkeren, E. van; Hoek, A.H.A.M. van; Roda Husman, A.N. de; Blaak, H. ; Havelaar, A.H. ; Mevius, D.J. ; Heederik, D.J.J. - \ 2018
    Journal of Antimicrobial Chemotherapy 73 (2018)2. - ISSN 0305-7453 - p. 339 - 347.
    Background: In recent years, ESBL/AmpC-producing Escherichia coli ESBL/AmpC-EC) have been isolated with increasing frequency from animals, food, environmental sources and humans. With incomplete and scattered evidence, the contribution to the human carriage burden from these reservoirs remains unclear.
    Objectives: To quantify molecular similarities between different reservoirs as a first step towards risk attribution.
    Methods: Pooled data on ESBL/AmpC-EC isolates were recovered from 35 studies in the Netherlands comprising.27 000 samples, mostly obtained between 2005 and 2015. Frequency distributions of ESBL/AmpC genes from 5808 isolates and replicons of ESBL/AmpC-carrying plasmids from 812 isolates were compared across 22 reservoirs through proportional similarity indices (PSIs) and principal component analyses (PCAs).
    Results: Predominant ESBL/AmpC genes were identified in each reservoir. PCAs and PSIs revealed close human–animal ESBL/AmpC gene similarity between human farming communities and their animals (broilers and pigs) (PSIs from 0.8 to 0.9). Isolates from people in the general population had higher similarities to those from human clinical settings, surface and sewage water and wild birds (0.7–0.8), while similarities to livestock or food reservoirs were lower (0.3–0.6). Based on rarefaction curves, people in the general population had more diversity in ESBL/AmpC genes and plasmid replicon types than those in other reservoirs.
    Conclusions: Our ‘One Health’ approach provides an integrated evaluation of the molecular relatedness of ESBL/AmpC-EC from numerous sources. The analysis showed distinguishable ESBL/AmpC-EC transmission cycles in different hosts and failed to demonstrate a close epidemiological linkage of ESBL/AmpC genes and plasmid replicon types between livestock farms and people in the general population.
    Samenvatting ESBL-Attributieanalyse (ESBLAT) : Op zoek naar de bronnen van antibioticaresistentie bij de mens
    Mevius, Dik ; Heederik, Dick ; Duijkeren, Engeline ; Veldman, Kees ; Essen, Alieda van; Kant, Arie ; Liakopoulos, Apostolos ; Geurts, Yvon ; Pelt, Wilfrid van; Mughini Gras, Lapo ; Schmitt, Heike ; Dierikx, Cindy ; Hoek, Angela van; Evers, Eric ; Roda Husman, Annemaria de; Blaak, Hetty ; Dissel, Jaap van; Smid, Joost ; Dohmen, Wietske ; Dorado-Garcia, Alejandro ; Havelaar, Arie ; Hordijk, Joost ; Wagenaar, Jaap ; Fluit, Ad ; Bunt, Gerrita van den; Bonten, Marc ; Velthuis, Annet ; Heuvelink, Annet ; Buter, Rianne ; Gonggrijp, Maaike ; Santman-Berends, Inge ; Lam, Theo ; Urlings, Bert ; Heres, Lourens ; Bouwknecht, Martijn ; Groot, Jacques de - \ 2018
    Netherlands : De Stichting TKI Agri&Food (TKI) - 11 p.
    Rapport ESBL-Attributieanalyse (ESBLAT) : Op zoek naar de bronnen van antibioticaresistentie bij de mens
    Mevius, Dik ; Heederik, Dick ; Duijkeren, Engeline ; Veldman, Kees ; Essen, Alieda van; Kant, Arie ; Liakopoulos, Apostolos ; Geurts, Yvon ; Pelt, Wilfrid van; Mughini Gras, Lapo ; Schmitt, Heike ; Dierikx, Cindy ; Hoek, Angela van; Evers, Eric ; Roda Husman, Annemaria de; Blaak, Hetty ; Dissel, Jaap van; Smid, Joost ; Dohmen, Wietske ; Dorado-Garcia, Alejandro ; Havelaar, Arie ; Hordijk, Joost ; Wagenaar, Jaap ; Fluit, Ad ; Bunt, Gerrita van den; Bonten, Marc ; Velthuis, Annet ; Heuvelink, Annet ; Buter, Rianne ; Gonggrijp, Maaike ; Santman-Berends, Inge ; Lam, Theo ; Urlings, Bert ; Heres, Lourens ; Bouwknecht, Martijn ; Groot, Jacques de - \ 2018
    Netherlands : De Stichting TKI Agri&Food (TKI) - 73
    Verkenning van de microbiologische risico’s van mest voor de gezondheid : Op basis van een systematisch literatuuronderzoek
    Leuken, J.P.G. van; Hoeksma, P. ; Nijsten, D.R.E. ; Schijven, J.F. ; Schmitt, H. ; Roda Husman, A.N. de - \ 2017
    Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM rapport 2017-0100) - 55
    Environmental surveillance during an outbreak of tularaemia in hares, the Netherlands, 2015
    Janse, Ingmar ; Maas, M. ; Rijks, J.M. ; Koene, M. ; Plaats, R.Q. van der; Engelsma, M. ; Tas, P.W.L. ; Braks, M. ; Stroo, A. ; Notermans, D.W. ; Vries, M.C. de; Reubsaet, F.A.G. ; Fanoy, E. ; Swaan, C.M. ; Kik, M.J. ; Ijzer, J. ; Jaarsma, R.I. ; Wieren, S. van; Roda Husman, A.M. de; Passel, M. van; Roest, H. ; Giessen, J. van der - \ 2017
    Eurosurveillance 22 (2017)35. - ISSN 1025-496X
    Tularaemia, a disease caused by the bacterium Francisella tularensis, is a re-emerging zoonosis in the Netherlands. After sporadic human and hare cases occurred in the period 2011 to 2014, a cluster of F. tularensis-infected hares was recognised in a region in the north of the Netherlands from February to May 2015. No human cases were identified, including after active case finding. Presence of F. tularensis was investigated in potential reservoirs and transmission routes, including common voles, arthropod vectors and surface waters. F. tularensis was not detected in common voles, mosquito larvae or adults, tabanids or ticks. However, the bacterium was detected in water and sediment samples collected in a limited geographical area where infected hares had also been found. These results demonstrate that water monitoring could provide valuable information regarding F. tularensis spread and persistence, and should be used in addition to disease surveillance in wildlife.
    Microbiologisch veilig water: oude en nieuwe bedreigingen vragen om een hernieuwde aanpak
    Bel, Nikki van; Smeets, Patrick ; Roda Husman, Ana Maria de; Vermeulen, L.C. ; Vanysacker, Louise - \ 2017
    H2O online (2017). - 8
    Een groot deel van de wereld heeft geen toegang tot microbiologisch veilig drinkwater. Maar ook in landen met veilig drinkwater moeten we alert zijn op ziekteverwekkende virussen en bacteriën in water als dat wordt gebruikt voor recreatie, landbouw of als bron voor drinkwater. Naast de bekende microbiologische bedreigingen zijn er ook nieuwe bedreigingen waarvoor snellere en nieuwe meetmethoden en waterzuiveringstechnieken moeten worden ontwikkeld. Op veel vlakken in de watercyclus vindt vernieuwing plaats die kan worden toegepast om het water microbiologisch veilig te maken en te houden.
    Clinically relevant fungi in water and on surfaces in an indoor swimming pool facility
    Ekowati, Yuli ; Diepeningen, Anne D. van; Ferrero, Giuliana ; Kennedy, Maria D. ; Roda Husman, Ana Maria de; Schets, Franciska M. - \ 2017
    International Journal of Hygiene and Environmental Health 220 (2017)7. - ISSN 1438-4639 - p. 1152 - 1160.
    Cleaning - Clinical fungi - Diversity - Exposure - Occurrence - Spatial distribution
    The density of fungal contamination and the fungal diversity in an indoor swimming pool facility were assessed. A total of 16 surface samples and 6 water samples were analysed by using a combination of different (semi-) selective culture media. Isolated fungal colonies were identified to the genus or species level by sequencing of the internal transcribed spacer (ITS). The highest fungal counts in water and on surfaces were in the recreational pool (17CFU/100mL) and on a flexibeam (5.8CFU/cm2), respectively as compared with low counts (<0.1CFU/cm2) on the diving platform, bench tops and walls. The 357 obtained isolates belonged to 79 species and species complexes, 42 of which known as clinically relevant. Phialophora oxyspora (13.7%) and Phoma spp. (12.3%) were the most frequently identified groups. We demonstrated that despite chlorine treatment and regular cleaning of surfaces both water and surfaces were commonly infested with fungi, including many clinically relevant species.
    Bronnen van antibioticaresistentie in het milieu en mogelijke maatregelen
    Schmitt, H. ; Blaak, H. ; Kemper, M. ; Passel, M. van; Hierink, F. ; Leuken, J. van; Roda Husman, A.M. de; Grinten, E. van der; Rutgers, M. ; Schijven, J. ; Man, H. de; Hoeksma, P. ; Zuidema, T. - \ 2017
    Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM rapport 2017-0058) - 110
    Het RIVM heeft in samenwerking met andere instituten onderzocht hoeveel resistente bacteriën via afvalwater in het Nederlandse oppervlaktewater terechtkomen. Afvalwater is, naast mest, de belangrijkste bron waardoor antibioticaresistente bacteriën in het milieu belanden. In 60 tot 100% van het onderzochte afvalwater zitten bijzonder resistente micro-organismen(BMRO), zoals ESBL-producerende E. coli en carbapenemresistente Enterobacteriaceae. Daarnaast zijn resten van antibiotica in het afvalwater gevonden.
    Veehouderij en Gezondheid Omwonenden (aanvullende studies) : analyse van gezondheidseffecten, risicofactoren en uitstoot van bio-aerosolen
    Hagenaars, Thomas ; Hoeksma, Paul ; Roda Husman, Ana Maria de; Swart, Arno ; Wouters, Inge - \ 2017
    Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM rapport 2017-0062) - 66
    Uit luchtmetingen in de woonomgeving blijkt dat de concentratie endotoxinen in de lucht toeneemt naarmate de afstand tot een veehouderij kleiner wordt of het aantal veehouderijen in een gebied (de dichtheid) groter wordt. Endotoxinen zijn kleine onderdelen van micro-organismen die luchtwegirritatie en ontstekingsreacties kunnen veroorzaken. Veehouderijsectoren met de hoogste uitstoot van fijnstof, zoals pluimvee- en varkenshouderij, dragen duidelijk bij aan de concentratie van endotoxinen in de leefomgeving. Opvallend is dat ook sectoren van de veehouderij die niet bekendstaan om een hoge uitstoot van stoffen toch substantieel lijken bij te dragen aan de concentratie van endotoxinen in de leefomgeving. Veehouderijen uit deze sectoren zijn in grote aantallen in het VGO-gebied vertegenwoordigd.
    Role of the Environment in the Transmission of Antimicrobial Resistance to Humans: A Review
    Huijbers, P.M.C. ; Blaak, H. ; Jong, M.C.M. de; Graat, E.A.M. ; Vandenbroucke-Grauls, C.M.J.E. ; Roda Husman, A.M. de - \ 2015
    Environmental Science and Technology 49 (2015)20. - ISSN 0013-936X - p. 11993 - 12004.
    To establish a possible role for the natural environment in the transmission of clinically relevant AMR bacteria to humans, a literature review was conducted to systematically collect and categorize evidence for human exposure to extended-spectrum ß-lactamase-producing Enterobacteriaceae, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus spp. in the environment. In total, 239 datasets adhered to inclusion criteria. AMR bacteria were detected at exposure-relevant sites (35/38), including recreational areas, drinking water, ambient air, and shellfish, and in fresh produce (8/16). More datasets were available for environmental compartments (139/157), including wildlife, water, soil, and air/dust. Quantitative data from exposure-relevant sites (6/35) and environmental compartments (11/139) were scarce. AMR bacteria were detected in the contamination sources (66/66) wastewater and manure, and molecular data supporting their transmission from wastewater to the environment (1/66) were found. The abundance of AMR bacteria at exposure-relevant sites suggests risk for human exposure. Of publications pertaining to both environmental and human isolates, however, only one compared isolates from samples that had a clear spatial and temporal relationship, and no direct evidence was found for transmission to humans through the environment. To what extent the environment, compared to the clinical and veterinary domains, contributes to human exposure needs to be quantified. AMR bacteria in the environment, including sites relevant for human exposure, originate from contamination sources. Intervention strategies targeted at these sources could therefore limit emission of AMR bacteria to the environment
    Tracing enteric viruses in the European berry fruit supply chain
    Maunula, L. ; Kaupke, A. ; Vasickova, P. ; Soderberg, K. ; Kozyra, I. ; Lazic, S. ; Poel, W.H.M. van der; Bouwknegt, M. ; Rutjes, S. ; Willems, K.A. ; Moloney, R. ; Agostino, M. D'; Husman, A.M.D. ; Bonsdorff, C.H. ; Rzezutka, A. ; Pavlik, I. ; Petrovic, T. ; Cook, N. - \ 2013
    International Journal of Food Microbiology 167 (2013)2. - ISSN 0168-1605 - p. 177 - 185.
    hepatitis-e virus - reverse transcription-pcr - time rt-pcr - waste-water - norovirus outbreaks - frozen raspberries - food safety - a virus - transmission - infection
    In recent years, numerous foodborne outbreaks due to consumption of berry fruit contaminated by human enteric viruses have been reported. This European multinational study investigated possible contamination routes by monitoring the entire food chain for a panel of human and animal enteric viruses. A total of 785 samples were collected throughout the food production chain of four European countries (Czech Republic, Finland, Poland and Serbia) during two growing seasons. Samples were taken during the production phase, the processing phase, and at point-of-sale. Samples included irrigation water, animal faeces, food handlers' hand swabs, swabs from toilets on farms, from conveyor belts at processing plants, and of raspberries or strawberries at points-of-sale; all were subjected to virus analysis. The samples were analysed by real-time (reverse transcription, RT)-PCR, primarily for human adenoviruses (hAdV) to demonstrate that a route of contamination existed from infected persons to the food supply chain. The analyses also included testing for the presence of selected human (norovirus, NoV GI, NoV GII and hepatitis A virus, HAV), animal (porcine adenovirus, pAdV and bovine polyomavirus, bPyV) and zoonotic (hepatitis E virus, HEV) viruses. At berry production, hAdV was found in 9.5%, 5.8% and 9.1% of samples of irrigation water, food handlers' hands and toilets, respectively. At the processing plants, hAdV was detected in one (2.0%) swab from a food handler's hand. At point-of-sale, the prevalence of hAdV in fresh raspberries, frozen raspberries and fresh strawberries, was 0.7%, 3.2% and 2.0%, respectively. Of the human pathogenic viruses, NoV GII was detected in two (3.6%) water samples at berry production, but no HAV was detected in any of the samples. HEV-contaminated frozen raspberries were found once (2.6%). Animal faecal contamination was evidenced by positive pAdV and bPyV assay results. At berry production, one water sample contained both viruses, and at point-of-sale 5.7% and 13% of fresh and frozen berries tested positive for pAdV. At berry production hAdV was found both in irrigation water and on food handler's hands, which indicated that these may be important vehicles by which human pathogenic viruses enter the berry fruit chain. Moreover, both zoonotic and animal enteric viruses could be detected on the end products. This study gives insight into viral sources and transmission routes and emphasizes the necessity for thorough compliance with good agricultural and hygienic practice at the farms to help protect the public from viral infections. (C) 2013 Elsevier B.V. All rights reserved.
    Virus hazards from food, water and other contaminated environments
    Rodriguez-Lázaro, D. ; Cook, N. ; Ruggeri, F.M. ; Sellwood, J. ; Nasser, A. ; Nascimento, M.S. ; Agostino, M. D'; Santos, R. ; Saiz, J.C. ; Rzezutka, A. ; Bosch, A. ; Girones, R. ; Carducci, A. ; Muscullo, M. ; Kovac, K. ; Diez-Valcarce, M. ; Vantarakis, A. ; Bonsdorff, C.H. ; Roda Husman, A.M. de; Hernández, M. ; Poel, W.H.M. van der - \ 2012
    FEMS Microbiology Reviews 36 (2012)4. - ISSN 0168-6445 - p. 786 - 814.
    hepatitis-e-virus - reverse transcription-pcr - human enteric viruses - polymerase-chain-reaction - norwalk-like virus - cell-culture-pcr - time rt-pcr - sequence-based amplification - human pathogenic viruses - treated drinking-water
    Numerous viruses of human or animal origin can spread in the environment and infect people via water and food, mostly through ingestion and occasionally through skin contact. These viruses are released into the environment by various routes including water run-offs and aerosols. Furthermore, zoonotic viruses may infect humans exposed to contaminated surface waters. Foodstuffs of animal origin can be contaminated, and their consumption may cause human infection if the viruses are not inactivated during food processing. Molecular epidemiology and surveillance of environmental samples are necessary to elucidate the public health hazards associated with exposure to environmental viruses. Whereas monitoring of viral nucleic acids by PCR methods is relatively straightforward and well documented, detection of infectious virus particles is technically more demanding and not always possible (e.g. human norovirus or hepatitis E virus). The human pathogenic viruses that are most relevant in this context are nonenveloped and belong to the families of the Caliciviridae, Adenoviridae, Hepeviridae, Picornaviridae and Reoviridae. Sampling methods and strategies, first-choice detection methods and evaluation criteria are reviewed.
    Multicenter Collaborative Trial Evaluation of a Method for Detection of Human Adenoviruses in Berry Fruit
    Agostino, C. D'; Cook, N. ; Bartolo, I. Di; Ruggeri, F.M. ; Berto, A. ; Martelli, F. ; Banks, M. ; Vasickova, P. ; Kralik, P. ; Pavlik, I. ; Kokkinos, P. ; Vantarakis, A. ; Söderberg, K. ; Maunula, L. ; Verhaelen, K. ; Rutjes, S. ; Roda Husman, A.M. De; Hakze-van der Honing, R.W. van der; Poel, W.H.M. van der; Kaupke, A. ; Kozyra, I. ; Rzezutka, A. ; Prodanov, J. ; Lazic, S. ; Petrovic, T. ; Carratala, A. ; Gironés, R. ; Diez-Valcarce, M. ; Hernandez, M. ; Rodriguez-Lazaro, D. - \ 2012
    Food Analytical Methods 5 (2012)1. - ISSN 1936-9751 - p. 1 - 7.
    pcr-based method - listeria-monocytogenes - international standard - enteric viruses - food - validation - water - contamination - environment - organisms
    The qualitative performance characteristics of a qPCR-based method to detect human adenoviruses in raspberries were determined through a collaborative trial involving 11 European laboratories. The method incorporated a sample process control (murine norovirus) and an internal amplification control. Trial sensitivity or correct identification of 25-g raspberry samples artificially contaminated with between 5×102 and 5×104 PFU was 98.5%; the accordance and concordance were 97.0%. The positive predictive value was 94.2%. The trial specificity or percentage correct identification of non-artificially contaminated samples was 69.7%; the accordance was 80.0% and the concordance was 61.7%. The negative predictive value was 100%. Application of a method for the detection of human adenoviruses in food samples could be useful for routine monitoring for food safety management. It would help to determine if a route of contamination exists from human source to food supply chain which pathogenic viruses such as norovirus and hepatitis A virus could follow.
    Estimation of the Likelihood of Fecal-Oral HEV Transmission Among Pigs
    Bouwknegt, M. ; Teunis, P.F.M. ; Frankena, K. ; Jong, M.C.M. de; Rode Husman, A.M. de - \ 2011
    Risk Analysis 31 (2011)6. - ISSN 0272-4332 - p. 940 - 950.
    hepatitis-e-virus - local grocery stores - rt-pcr assay - united-states - experimental-infection - livers sold - sows feces - swine - japan - inactivation
    Sources for human hepatitis E virus (HEV) infections of genotype 3 are largely unknown. Pigs are potential animal reservoirs for HEV. Intervention at pig farms may be desired when pigs are confirmed as a source for human infections, requiring knowledge about transmission routes. These routes are currently understudied. The current study aims to quantify the likelihood of pig feces in causing new HEV infections in pigs due to oral ingestion. We estimated the daily infection risk for pigs by modeling the fate of HEV in the fecal–oral (F–O) pathway. Using parameter values deemed most plausible by the authors based on current knowledge the daily risk of infection was 0.85 (95% interval: 0.03–1). The associated expected number of new infections per day was ~4 (2.5% limit 0.1, the 97% limit tending to infinity) compared to 0.7 observed in a transmission experiment with pigs, and the likelihood of feces causing the transmission approached 1. In alternative scenarios, F–O transmission of HEV was also very likely to cause new infections. By reducing the total value of all explanatory variables by 2 orders of magnitude, the expected numbers of newly infected pigs approached the observed number. The likelihood of F–O transmission decreased by decreasing parameter values, allowing for at most 94% of infections being caused by additional transmission routes. Nevertheless, in all scenarios F–O transmission was estimated to contribute to HEV transmission. Thus, despite the difficulty in infecting pigs with HEV via oral inoculation, the F–O route is likely to cause HEV transmission among pigs.
    Hepatitis E virus infections in pigs : transmission dynamics and human exposure
    Bouwknegt, M. - \ 2009
    Wageningen University. Promotor(en): Mart de Jong; Wim van der Poel, co-promotor(en): A.M. de Roda Husman. - [S.l. : S.n. - ISBN 9789085855194 - 150
    varkens - hepatitis e-virus - ziekteoverdracht - zoönosen - ziekteprevalentie - blootstelling - ziekten overgebracht door voedsel - volksgezondheid - pigs - hepatitis e virus - disease transmission - zoonoses - disease prevalence - exposure - foodborne diseases - public health
    In dit promotieonderzoek is de transmissie dynamiek van Hepatitis E virus (HEV) bij varkens onderzocht, alsmede de potentiële blootstelling van de Nederlandse bevolking aan HEV uit varkens. Om te onderzoeken of HEV spreidt onder varkens is een experiment opgezet bestaande uit 10 infectieketens. Elke keten bestond uit één intraveneus geïnfecteerd varken ( iv‐varkens) en drie HEV‐gevoelige varkens (contactvarkens). Aan elk van de 10 iv‐varkens is een HEV‐naïef varken blootgesteld (één‐op‐één blootstelling). Indien dit naïeve varken werd geïnfecteerd, werd een volgend HEV‐naïef varken uit de keten aan het zojuist geïnfecteerde varken blootgesteld.
    The course of hepatitis E virus infection in pigs after contact-infection and intravenous inoculation
    Bouwknegt, M. ; Rutjes, S.A. ; Reusken, C.B.E.M. ; Stockhofe-Zurwieden, N. ; Frankena, K. ; Jong, M.C.M. de; Roda Husman, A.M. de; Poel, W.H.M. van der - \ 2009
    BMC Veterinary Research 5 (2009). - ISSN 1746-6148 - 12 p.
    rt-pcr assay - swine - netherlands - transmission - hev - liver - serum - exposure - japan - risk
    Background - Worldwide, hepatitis E virus (HEV) genotype 3 is observed in pigs and transmission to humans is implied. To be able to estimate public health risks from e.g. contact with pigs or consumption of pork products, the transmission routes and dynamics of infection should be identified. Hence, the course of HEV-infection in naturally infected pigs should be studied. Results - To resemble natural transmission, 24 HEV-susceptible pigs were infected either by one-to-one exposure to intravenously inoculated pigs (C1-pigs; n = 10), by one-to-one exposure to contact-infected pigs (C2-pigs: n = 7; C3-pigs: n = 5) or due to an unknown non-intravenous infection route (one C2-pig and one C3-pig). The course of HEV-infection for contact-infected pigs was characterized by: faecal HEV RNA excretion that started at day 7 (95% confidence interval: 5¿10) postexposure and lasted 23 (19¿28) days; viremia that started after 13 (8¿17) days of faecal HEV RNA excretion and lasted 11 (8¿13) days; antibody development that was detected after 13 (10¿16) days of faecal HEV RNA excretion. The time until onset of faecal HEV RNA excretion and onset of viremia was significantly shorter for iv-pigs compared to contact-infected pigs, whereas the duration of faecal HEV RNA excretion was significantly longer. At 28 days postinfection HEV RNA was detected less frequently in organs of contact-infected pigs compared to iv-pigs. For contact-infected pigs, HEV RNA was detected in 20 of 39 muscle samples that were proxies for pork at retail and in 4 of 7 urine samples. Conclusion - The course of infection differed between infection routes, suggesting that contact-infection could be a better model for natural transmission than iv inoculation. Urine and meat were identified as possible HEV-sources for pig-to-pig and pig-to-human HEV transmission
    Multiple exposures during a norovirus outbreak on a river-cruise sailing through Europe, 2006.
    Verhoef, L. ; Boxman, I.L. ; Duizer, E. ; Rutjes, S.A. ; Vennema, H. ; Friesema, I.H. ; Roda Husman, A.M. de; Koopmans, M. - \ 2008
    Eurosurveillance 13 (2008)24. - ISSN 1025-496X

    In the summer of 2006, several cruise-related viral gastroenteritis outbreaks were reported in Europe. One report came from a river-cruise, belonging to a ship-owner who had two other ships with outbreaks. This situation warranted onsite investigation in order to identify a potential common source of infection. A retrospective cohort study was performed among 137 people on board. Epidemiological questionnaire data were analysed using logistic regression. Stool, food, water and surface samples were collected for norovirus detection. Norovirus GGII.4-2006b was responsible for 48 gastroenteritis cases on this ship as confirmed in six patients. Identical norovirus sequences were detected in stool samples, on surfaces and in tap water. Epidemiological and microbiological data indicated multiple exposures contributing to the outbreak. Microbiological results demonstrated person-to-person transmission to be clearly present. Epidemiological results indicated that consuming tap water was a risk factor; however, this could not be concluded definitively on the basis of the available data. A common source for all cruise-related outbreaks was unlikely. The ongoing outbreaks on this ship demonstrated that evidence based guidelines on effective disinfection strategies are needed.

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