14 results on '"Lodder-Verschoor F"'
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2. Vergelijking van methoden voor detectie en typering van virussen in voedsel : Hepatitis A-virus en rotavirus
- Author
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LZO, cib, Rutjes SA, Lodder-Verschoor F, de Roda Husman AM, LZO, cib, Rutjes SA, Lodder-Verschoor F, and de Roda Husman AM
- Abstract
RIVM rapport:Voedseloverdraagbare virussen kunnen vooral worden overgedragen via voedsel dat niet of nauwelijks is verhit. Voorbeelden zijn schelpdieren, verse groente en fruit en kant-en-klare producten, zoals belegde broodjes en salades. Om de bron van een voedselinfectie te kunnen achterhalen wordt onderzocht of op het voedsel en in de patiënt hetzelfde virus aanwezig is. Tot nu toe werd hiervoor bij de patiënt een ander stukje van het genetisch materiaal van het virus aangetoond dan bij het virus dat aanwezig is op voedsel of in water. Door deze werkwijze was het niet mogelijk om de aangetroffen virussen te vergelijken, waardoor de besmettingsbron niet kon worden vastgesteld. Uit onderzoek van het RIVM blijkt nu dat zowel voor hepatitis A-virus als voor rotavirus één stukje genetisch materiaal kan worden aangetoond in de drie soorten monsters. Dit maakt het eenvoudiger om de bronnen van voedselgerelateerde virusinfecties te achterhalen. Voor het onderzoek zijn de verschillende methoden vergeleken die momenteel worden gebruikt om de bronnen van voedseloverdraagbare virusinfecties op te sporen. Virusonderzoek wordt vaak gedaan met de moleculaire techniek PCR (polymerase chain reaction), waarmee een deel van het genetisch materiaal van een virus wordt aangetoond. Er zijn verschillende PCR's beschikbaar waarmee verschillende delen van het genetisch materiaal worden gedetecteerd. Vaak wordt eerst aangetoond óf en welk virus aanwezig is (detectie). Vervolgens wordt bepaald om welk type virus het gaat (typering). Voor het onderliggende onderzoek zijn van twee virussen, hepatitis A-virus en rotavirus, meerdere detectie- en typerings-PCR's vergeleken. Voor beide virussen is bepaald welk stukje genetisch materiaal het best met PCR kan worden aangetoond om het in de mens, op voedsel en in water te kunnen detecteren. Daarnaast is bekeken welk stukje genetisch materiaal het meest geschikt is om het type virus vast te stellen (typerings-PCR). Voor beide virussen bleek dat de detectie-PCR, Foodborne viruses can be transmitted through the consumption of food that has had little or no treatment, such as shellfish, fresh produce and ready-to-eat food products. To be able to trace the source of a foodborne virus infection, viruses present in the food and in the patient have to be compared. Currently, a different part of the viral genome is detected in patients than in food and water samples, indicating that viruses cannot be compared and the source not established. Research by the National Institute for Public Health and the Environment (RIVM) has now determined which part of the viral genome of hepatitis A virus and rotavirus can be detected in all three sample types. This will facilitate the tracing of the source of foodborne virus infections. Several methods that are currently used for the tracing of viruses involved in foodborne infections were compared. Virus research is often done by the molecular technique PCR (polymerase chain reaction), which detects part of the genetic material of the virus. Several PCRs are available that target different parts of the viral genome. Generally, the presence of a virus in a suspected food item is determined by a detection PCR, after which the identity of the virus is established by a typing PCR. In the present study, several detection and typing PCRs specific for hepatitis A virus and rotavirus were compared. For both viruses it was determined which part of the viral genome was most efficiently detected in patients, food and water samples. Furthermore, the study showed which part of the viral genome was most suitable for typing the virus in the three different sample types. For both viruses, the detection PCR appeared to be more sensitive than the typing PCR, indicating that at low levels of contamination viruses may be detected, but cannot be typed. This means that viruses detected in the patient and in a suspected food product cannot always be conclusively determined as identical. If this is the case, then it re
- Published
- 2012
3. Prevalence of antibiotic resistant bacteria in the rivers Meuse, Rhine and New Meuse
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LZO, cib, Blaak H, van Rooijen SR, Schuijt MS, Docters van Leeuwen AE, Italiaander R, van den Berg HHJL, Lodder-Verschoor F, Schets FM, de Roda Husman AM, LZO, cib, Blaak H, van Rooijen SR, Schuijt MS, Docters van Leeuwen AE, Italiaander R, van den Berg HHJL, Lodder-Verschoor F, Schets FM, and de Roda Husman AM
- Abstract
RIVM rapport:In de grote Nederlandse rivieren de Maas, de Rijn en de Nieuwe Maas komen bacteriën voor waarvan hoge percentages resistent zijn tegen een of meer soorten antibiotica. Dit blijkt uit verkennend onderzoek van het RIVM. Blootstelling via oppervlaktewater: Als mensen aan verontreinigd oppervlaktewater blootgesteld worden, kunnen zij antibioticaresistente bacteriën binnenkrijgen. Dit kan bijvoorbeeld via recreatiewater of via water dat gebruikt worden om gewassen te besproeien. Dergelijk contact kan risico's voor de volksgezondheid met zich meebrengen, omdat deze antibiotica nodig zijn om infecties te behandelen. Antibioticaresistente bacteriën kunnen op meerdere manieren in oppervlaktewater terechtkomen, bijvoorbeeld doordat mest van dieren die met antibiotica zijn behandeld, afspoelt naar het oppervlaktewater. Een andere oorzaak kan zijn dat gedeeltelijk gezuiverd of ongezuiverd afvalwater in oppervlaktewater wordt geloosd, bijvoorbeeld afkomstig van ziekenhuizen waar mensen zijn behandeld met antibiotica. In totaal waren gemiddeld eenderde tot de helft van alle Escherichia coli en van de intesintale enterococcen resistent tegen een of meer soorten antibiotica. In sommige van de monsters werden antibioticaresistente stammen van Staphylococcus aureus, Campylobacter en Salmonella aangetoond. De meeste van deze bacteriën zijn darmbacteriën; Staphylococcus aureus komt vooral voor op de huid, en in de neus en keel van mensen. Diverse risico's: De risico's kunnen zich op verschillende manieren manifesteren. Op de eerste plaats kunnen mensen die aan antibioticaresistente bacteriën worden blootgesteld, daarvan ziek worden en vervolgens problemen krijgen bij de behandeling ervan. Daarnaast is het mogelijk dat mensen die worden blootgesteld aan de resistente bacteriën zelf niet ziek worden, maar deze overdragen aan mensen met verminderde weerstand, zoals ziekenhuispatiënten en ouderen. Deze groep mensen kan vervolgens wel ziek worden door deze bacteriën. Ten slotte is er het ri, A high percentage of bacteria in large Dutch rivers is resistant to one or more antibiotics. This was demonstrated in an exploratory study performed at the RIVM. Exposure through surface water: If people come into contact with contaminated surface water, they risk exposure to bacteria that are resistant to one or more antibiotics. This may occur for instance during recreation in surface water or through water used for irrigation of crops. Because antibiotics are needed for treatment of infections, such contact may involve public health risks. Antibiotic resistant bacteria can end up in surface water by different routes, for example through run off of manure from animals treated with antibiotics to surface water. Another source may be the discharge of partially treated or untreated waste water, for instance derived from hospitals where people are treated with antibiotics. Overall, one third to half of all Escherichia coli and intestinal enterococci were resistant to one or more antibiotics. In some of the samples antibiotic resistant strains of Staphylococcus aureus, Campylobacter and Salmonella were detected. Most of these bacteria are gut bacteria; Staphylococcus aureus is predominantly present on people's skin and in their noses and throats. Diverse risks: The risks can manifest themselves in different ways. Firstly, after exposure to antibiotic resistant bacteria people may develop disease caused by these bacteria, which may therefore be hard to treat. Additionally, people may not become ill themselves, but transfer the resistant bacteria to people who are more vulnerable, such as hospital patients and the elderly. Subsequently, this category of people can develop disease. Finally, there is a risk that the antibiotic resistant bacteria establish themselves in the gut and transfer resistance genes to disease-causing bacteria if these are subsequently ingested Further research on public health risks: Data on the prevalence of antibiotic resistant bacteria in surfac
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- 2012
4. Harmonisatie van virusdiagnostiek in humane, voedsel- en omgevingsmonsters. Inventarisatie van methoden toegepast door VWA en RIVM
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LZO, Rutjes S, Lodder-Verschoor F, de Roda Husman AM, LZO, Rutjes S, Lodder-Verschoor F, and de Roda Husman AM
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- 2009
5. Development and Application of a Tool To Assess Laboratory Hygiene in Contained-Use Facilities
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Rutjes, S. A., primary, Lodder-Verschoor, F., additional, Tijssen, J. P., additional, and de Roda Husman, A. M., additional
- Published
- 2011
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6. Hepatitis E virus RNA in commercially available porcine livers in The Netherlands
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Bouwknegt, M., primary, Lodder-Verschoor, F., additional, van der Poel, W. H. M., additional, Rutjes, S. A., additional, and de Roda Husman, A. M., additional
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- 2007
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7. Year-Round Screening of Noncommercial and Commercial Oysters for the Presence of Human Pathogenic Viruses
- Author
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Lodder-Verschoor, F., primary, De Roda Husman, A.M., additional, Van Den Berg, H.H.J.L., additional, Stein, A., additional, Van Pelt-Heerschap, H.M.L., additional, and Van Der Poel, W.H.M., additional
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- 2005
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8. Sources of hepatitis E virus genotype 3 in The Netherlands.
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Rutjes SA, Lodder WJ, Lodder-Verschoor F, van den Berg HH, Vennema H, Duizer E, Koopmans M, de Roda Husman AM, Rutjes, Saskia A, Lodder, Willemijn J, Lodder-Verschoor, Froukje, van den Berg, Harold H J L, Vennema, Harry, Duizer, Erwin, Koopmans, Marion, and de Roda Husman, Ana Maria
- Abstract
Non-travel-related hepatitis E virus (HEV) genotype 3 infections in persons in the Netherlands may have a zoonotic, foodborne, or water-borne origin. Possible reservoirs for HEV transmission by water, food, and animals were studied. HEV genotype 3/open reading frame 2 sequences were detected in 53% of pig farms, 4% of wild boar feces, and 17% of surface water samples. HEV sequences grouped within 4 genotype 3 clusters, of which 1 is so far unique to the Netherlands. The 2 largest clusters contained 35% and 43% of the animal and environmental sequences and 75% and 6%, respectively, of human HEV sequences obtained from a study on Dutch hepatitis E patients. This finding suggests that infection risk may be also dependent on transmission routes other than the ones currently studied. Besides the route of exposure, virus characteristics may be an important determinant for HEV disease in humans. [ABSTRACT FROM AUTHOR]
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- 2009
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9. Virus transfer proportions between gloved fingertips, soft berries, and lettuce, and associated health risks.
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Verhaelen K, Bouwknegt M, Carratalà A, Lodder-Verschoor F, Diez-Valcarce M, Rodríguez-Lázaro D, de Roda Husman AM, and Rutjes SA
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- Humans, Reverse Transcriptase Polymerase Chain Reaction, Risk Assessment, Food Handling standards, Food Microbiology, Fruit virology, Gloves, Protective virology, Lactuca virology
- Abstract
Multiple outbreaks of human norovirus (hNoV) have been associated with fresh produce, such as soft berries and lettuce. Even though food handlers are considered an important source for the introduction of hNoV into food chains, their contribution to public health risks associated with hNoV remains unknown. To assess to which extent food handlers contribute to the introduction and spread of hNoV in fresh produce chains quantitative virus transfer data are needed. We estimated transfer proportions of hNoV GI.4, GII.4, murine norovirus (MNV-1), a culturable surrogate of hNoV, and human adenovirus (hAdV-2), a human pathogen proposed as an indicator for human faecal pollution, between gloved fingertips and raspberries, strawberries, and lettuce, by quantitative RT-PCR and cell culture if applicable. Virus transfer proportions were corrected for virus-matrix specific recoveries, and variability and uncertainty of the parameters were estimated. Virus transfer from gloves to soft berries was generally lower as compared to lettuce, with mean transfer proportions ranging between 0.1 to 2.3% and 9 to 10% for infectious MNV-1 and hAdV-2, respectively. Transfer from produce to glove was mostly greater than transfer from glove to produce, adding to the likelihood of virus transfer due to cross contamination from contaminated produce via food handlers. HNoV GI.4 and hNoV GII.4 showed no significant difference between their mean transfer proportions. Using the estimated transfer proportions, we studied the impact of low and high transfer proportions on the public health risk, based on a scenario in which a food handler picked raspberries with contaminated fingertips. Given the made assumptions, we could show that for a pathogen as infectious as hNoV, low transfer proportions may pose a greater public health risk than high transfer proportions, due to a greater viral spread. We demonstrated the potential of food handlers in spreading hNoV in food chains, showing that prevention of virus contamination on food handlers' hands is crucial for food safety. Nevertheless, complete prevention of virus contamination on fresh produce cannot be achieved in reality, and reliable and effective intervention measures are consequently required. We estimated that, especially for low transfer proportions, a robust one log10-unit reduction of infectious hNoV on contaminated produce, and on food handlers' hands, could lower the public health risk substantially. Using the obtained data in quantitative risk assessment will aid in elucidating the contribution of food handlers in hNoV transmission., (© 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
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10. Persistence of human norovirus GII.4 and GI.4, murine norovirus, and human adenovirus on soft berries as compared with PBS at commonly applied storage conditions.
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Verhaelen K, Bouwknegt M, Lodder-Verschoor F, Rutjes SA, and de Roda Husman AM
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- Animals, Cells, Cultured, Food Handling standards, Humans, Microbial Viability, Temperature, Adenoviruses, Human physiology, Food Microbiology, Fruit virology, Norovirus physiology, Sodium Chloride
- Abstract
Human noroviruses (hNoV) have been detected on soft fruits. Especially raspberries have been found to be associated with outbreaks of gastroenteritis suggesting persistence of hNoV on these fruits. Therefore, the persistence of hNoV GII.4 and GI.4, murine norovirus (MNV-1, a culturable surrogate for hNoV), and human adenovirus (hAdV, an indicator for human fecal contamination), on raspberries, strawberries and in phosphate buffered saline (PBS) at 4°C, 10°C and 21°C, mimicking commonly applied storage conditions was studied by molecular and cell culture techniques. Monophasic, biphasic and Weibull models were fitted to virus counts with maximum likelihood estimation. The tested viruses were persistent (≤0.5 log(10)-unit reduction in viral titer) under all studied conditions in PBS, at 4°C and 10°C on raspberries, and at 4°C on strawberries. The difference in viral persistence on raspberries and strawberries was most pronounced at 21°C. Here, infectious MNV-1 and hAdV particles decayed rapidly on strawberries with TFL-values (time for the first log(10)-unit reduction) of only 1day (95% CI of 0.6-1 and 0.8-1days, respectively). On raspberries, however, the TFL-value of infectious MNV-1 was found to likely exceed the shelf life of the berries with 3days (95% CI of 2.8-3.1days); hAdV remained infectious with only 0.3 log(10)-unit reduction (95% CI of 0.2-0.4) in viral titer. For hNoV GI, a TFL-value of 2days (95% CI 1-4days) was determined based on the targeted genome fragment, whereas the TFL-value of hNoV GII exceeded the shelf life of strawberries at 21°C. The greater viral persistence on raspberries as compared to strawberries, especially at 21°C, may at least in part explain why raspberries are more frequently associated with hNoV outbreaks than strawberries. Moreover, our results show that due to the high persistence of the virus already low contamination levels of the highly infectious hNoV may be associated with an infection risk of humans after consumption of raspberries. The estimated decay parameters and uncertainties of this study serve as important input requirements in the quantitative assessment of public health risks from the consumption of soft fruits., (Copyright © 2012 Elsevier B.V. All rights reserved.)
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- 2012
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11. Hepatitis E virus RNA in commercial porcine livers in The Netherlands.
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Bouwknegt M, Lodder-Verschoor F, van der Poel WH, Rutjes SA, and de Roda Husman AM
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- Animals, Biological Assay, Blotting, Southern methods, Food Microbiology, Genotype, Hepatitis E transmission, Hepatitis E virology, Humans, Netherlands, RNA, Viral chemistry, RNA, Viral genetics, Reverse Transcriptase Polymerase Chain Reaction methods, Risk Assessment, Sequence Homology, Swine virology, Swine Diseases transmission, Food Contamination analysis, Hepatitis E veterinary, Hepatitis E virus isolation & purification, Liver virology, Sus scrofa, Swine Diseases virology
- Abstract
Human hepatitis E virus (HEV) infections by genotype 3 strains in industrialized countries are hypothesized to be caused by pigs. To examine this hypothesis, the potential health risks of transmission routes should be examined. Possible foodborne transmission was studied by quantifying the presence and infectivity of HEV in commercial porcine livers in The Netherlands. A comparison of four tissue disruption and seven RNA extraction methods revealed that mechanical disruption followed by silica-based RNA extraction gave the highest RNA yields and was therefore employed on commercial porcine livers. Four (6.5%) of 62 porcine livers were HEV RNA positive by reverse transcriptase PCR and Southern blot hybridization. Each positive liver was estimated to contain approximately 65 PCR-detectable units per g. Sequences were obtained for three of four positive livers and classified as HEV genotype 3. Ninety-three percent similarity to Dutch human HEV sequences and 97% similarity to Dutch swine HEV sequences were observed. To determine whether positive livers contained infectious HEV particles, extracts from livers with known HEV RNA sequences were inoculated intravenously in pigs. Two control pigs were included: one was inoculated with a high dose known to result in infection (10(4) PCR-detectable units of HEV RNA), and the other was inoculated with a lower concentration of virus that equaled the concentration of PCR-detectable units in commercial livers ( approximately 20 PCR-detectable units). Infection was observed in the high-dose control, but not in other pigs, suggesting a dose-dependent response in pigs. Hence, the implications of HEV RNA in commercial porcine livers in The Netherlands are unknown. However, HEV RNA is present in commercial porcine livers, and sufficient heating of porcine livers before consumption as precautionary measure is recommended.
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- 2007
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12. Rapid virus detection procedure for molecular tracing of shellfish associated with disease outbreaks.
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de Roda Husman AM, Lodder-Verschoor F, van den Berg HH, Le Guyader FS, van Pelt H, van der Poel WH, and Rutjes SA
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- Animals, Chemical Precipitation, Disease Outbreaks, Feces virology, Humans, RNA, Viral analysis, Reagent Kits, Diagnostic, Reverse Transcriptase Polymerase Chain Reaction methods, Sensitivity and Specificity, Viruses pathogenicity, Food Contamination analysis, Ostreidae virology, Shellfish virology, Viruses isolation & purification
- Abstract
Detection of pathogenic viruses in oysters implicated in gastroenteritis outbreaks is often hampered by time-consuming, specialist virus extraction methods. Five virus RNA extraction methods were evaluated with respect to performance characteristics and sensitivity on artificially contaminated oyster digestive glands. The two most promising procedures were further evaluated on bioaccumulated and naturally contaminated oysters. The most efficient method was used to trace the source in an outbreak situation. Out of five RNA extraction protocols, PEG precipitation and the RNeasy Kit performed best with norovirus genogroup III-spiked digestive glands. Analyzing 24-h bioaccumulated oysters revealed a slightly better sensitivity with PEG precipitation, but the RNeasy Kit was less prone to concentrate inhibitors. The latter procedure demonstrated the presence of human noroviruses in naturally contaminated oysters and oysters implicated in an outbreak. In this outbreak, in four out of nine individually analyzed digestive glands, norovirus was detected. In one of the oysters and in one of the fecal samples of the clinical cases, identical norovirus strains were detected. A standard and rapid virus extraction method using the RNeasy Kit appeared to be most useful in tracing shellfish as the source in gastroenteritis outbreaks, and to be able to make effective and timely risk management decisions.
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- 2007
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13. Detection of noroviruses in foods: a study on virus extraction procedures in foods implicated in outbreaks of human gastroenteritis.
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Rutjes SA, Lodder-Verschoor F, van der Poel WH, van Duijnhoven YT, and de Roda Husman AM
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- Centrifugation, Consumer Product Safety, Disease Outbreaks, Filtration, Gastroenteritis epidemiology, Gastroenteritis virology, Humans, Dairy Products virology, Food Contamination analysis, Food Microbiology, Lactuca virology, Norovirus isolation & purification
- Abstract
Disease outbreaks in which foods are epidemiologically implicated as the common source are frequently reported. Noroviruses and enteric hepatitis A viruses are among the most prevalent causative agents of foodborne diseases. However, the detection of these viruses in foods other than shellfish is often time-consuming and unsuccessful. In this study, three virus concentration methods were compared: polyethylene glycol (PEG) plus NaCl, ultracentrifugation, and ultrafiltration. Two RNA extraction methods, TRIzol and RNeasy Mini Kit (Qiagen), were compared for detection of viruses in whipped cream and lettuce (as representatives of the dairy and vegetable-fruit food groups, respectively). A seeding experiment with canine calicivirus was conducted to determine the efficiency of each virus extraction procedure. The PEG-NaCl-TRIzol method was most efficient for the detection of viruses in whipped cream and the ultracentrifugation-RNeasy-Mini Kit procedure was best for detection on lettuce. Based on the seeding experiments, food items implicated in norovirus-associated gastroenteritis outbreaks were subjected to the optimal procedure for a specific composition and matrix. No noroviruses were detected in the implicated food items, possibly because the concentration of virus on the food item was too low or because of the presence of inhibitory factors. For each food group, a specific procedure is optimal. Inhibitory factors should be controlled in these procedures because they influence virus detection in food.
- Published
- 2006
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14. Round-robin comparison of methods for the detection of human enteric viruses in lettuce.
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Le Guyader FS, Schultz AC, Haugarreau L, Croci L, Maunula L, Duizer E, Lodder-Verschoor F, von Bonsdorff CH, Suffredini E, van der Poel WM, Reymundo R, and Koopmans M
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- Consumer Product Safety, Food Microbiology, Humans, Nucleic Acid Hybridization, Polyethylene Glycols, RNA, Viral isolation & purification, Sensitivity and Specificity, Caliciviridae isolation & purification, Food Contamination analysis, Lactuca virology, Poliovirus isolation & purification
- Abstract
Five methods that detect human enteric virus contamination in lettuce were compared. To mimic multiple contaminations as observed after sewage contamination, artificial contamination was with human calicivirus and poliovirus and animal calicivirus strains at different concentrations. Nucleic acid extractions were done at the same time in the same laboratory to reduce assay-to-assay variability. Results showed that the two critical steps are the washing step and removal of inhibitors. The more reliable methods (sensitivity, simplicity, low cost) included an elution/concentration step and a commercial kit. Such development of sensitive methods for viral detection in foods other than shellfish is important to improve food safety.
- Published
- 2004
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