Web-based Archive of RIVM Publications
Not a member yet
15852 research outputs found
Sort by
Relative contributions of pre-pandemic factors and intra-pandemic activities to differential COVID-19 risk among migrant and non-migrant populations in the Netherlands: lessons for future pandemic preparedness.
No full textAre older people worse off in 2040 regarding health and resources to deal with it? - Future developments in complex health problems and in the availability of resources to manage health problems in the Netherlands.
No full textImpact of vitamin B on rhamnose metabolism, stress defense and in-vitro virulence of Listeria monocytogenes.
No full textListeria monocytogenes is a facultative anaerobe which can cause a severe food-borne infection known as listeriosis. L. monocytogenes is capable of utilizing various nutrient sources including rhamnose, a naturally occurring deoxy sugar abundant in foods. L. monocytogenes can degrade rhamnose into lactate, acetate and 1,2-propanediol. Our previous study showed that addition of vitamin B12 stimulated anaerobic growth of L. monocytogenes on rhamnose due to the activation of bacterial microcompartments for 1,2-propanediol utilization (pdu BMC) with concomitant production of propionate and propanol. Notably, anaerobic 1,2-propanediol metabolism has been linked to virulence of enteric pathogens including Salmonella spp. and L. monocytogenes. In this study we investigated the impact of B12 and BMC activation on i) aerobic and anerobic growth of L. monocytogenes on rhamnose and ii) the level of virulence. We observed B12-induced pdu BMC activation and growth stimulation only in anaerobically grown cells. Comparative Caco-2 virulence assays showed that these pdu BMC-induced cells have significantly higher translocation efficiency compared to non-induced cells (anaerobic growth without B12; aerobic growth with or without B12), while adhesion and invasion capacity is similar for all cells. Comparative proteome analysis showed specific and overlapping responses linked to metabolic shifts, activation of stress defense proteins and virulence factors, with RNA polymerase sigma factor SigL, teichoic acid export ATP-binding protein TagH, DNA repair and protection proteins, RadA and DPS, and glutathione synthase GshAB, previously linked to activation of virulence response in L. monocytogenes, uniquely upregulated in anaerobically rhamnose grown pdu-induced cells. Our results shed light on possible effects of B12 on L. monocytogenes competitive fitness and virulence activation when utilizing rhamnose in anaerobic conditions encountered during transmission and the human intestine
Biosafety of two-dimensional molybdenum disulfide nanomaterials: Natural and engineered transformation pathways and their role in the toxicity profile
No full textSeasonal and inter-seasonal RSV activity in the European Region during the COVID-19 pandemic from autumn 2020 to summer 2022.
No full textEPS-corona formation on graphene family nanomaterials (GO, rGO and graphene) and its role in mitigating their toxic effects in the marine alga Chlorella sp.
No full textGFNs have widespread applications but can harm marine systems due to excessive use and improper disposal. Algae-secreted EPS can mitigate nanomaterial harm, but their impact on GFN toxicity is understudied. Hence, in the present study, we investigated the toxicity of three GFNs, graphene oxide (GO), reduced graphene oxide (rGO), and graphene, in pristine and EPS-adsorbed forms in the marine alga Chlorella sp. At an environmentally relevant concentration of 1 mgL-1, all three GFNs induced considerable oxidative stress and impeded growth and photosynthetic activity of the algae. The order of the toxic potential followed GO > rGO > graphene. The various facets of adsorption of EPS (1:1 mixture of loosely bound, and tightly bound EPS) on GFNs were investigated through microscopy, surface chemical analyses, fluorescence quenching studies, and isotherm and kinetics studies. Amongst the pristine GFNs treated with algal cells, GO was found to exert the maximum negative effects on algal growth. Upon adsorption of EPS over the GFNs, a significant decline in growth inhibition was observed compared to the respective pristine forms which strongly correlated with reduced oxidative stress and enhanced photosynthetic parameters in the cells. The formation of a layer of eco-corona after interaction of GFNs with EPS possibly caused a barrier effect which in turn diminished their toxic potential. The findings from the present investigation offer valuable insights into the environmental toxicity of GFNs and show that the eco-corona formation may lessen the risk posed by these materials in the marine environment
Effect of industrialization on the differences in sources and composition of ambient PM in two Southern Ontario locations.
No full textPM2.5 was sampled over a seven-year period (2013-2019) at two locations ∼50 km apart in Southern Ontario (concurrently for five years: 2015-2019). One is a heavily industrialized site (Hamilton), while the other was a rural site (Simcoe). To assess the impact of industrialization on the composition and sources of PM affecting air quality in these two locations, positive matrix factorization coupled with dispersion normalization (DN-PMF) was used to identify six and eight factors at Simcoe and Hamilton, respectively. The Simcoe factors in order of diminishing PM mass contribution were: particulate sulphate (pSO4), secondary organic aerosol (SOA), crustal matter, particulate nitrate (pNO3), biomass burning, and vehicular emissions. At Hamilton, the effects of industrialization were observed by the ∼36% higher average ambient PM2.5 concentration for the study period as well as the presence of factors unique to metallurgy, i.e., coking and steelmaking, compared to Simcoe. The coking and steelmaking factors contributed ∼15% to the PM mass at Hamilton. Seasonal variants of appropriate nonparametric trend tests with the associated slopes (Sen's) were used to assess statistically significant changes in the factor contributions to PM2.5 over time. Specifically at Hamilton, a significant decline in PM contributions was noted for coking (-0.03 μg/m³/yr or -4.1%/yr) while steelmaking showed no statistically significant decline over the study period. Other factors at Hamilton that showed statistically significant declines over the study period were: pSO4 (-0.27 μg/m³/yr or -12.6%/yr), biomass burning (-0.05 μg/m³/yr or -9.02%/yr), crustal matter (-0.03 μg/m³/yr or -5.28%/yr). These factors mainly accounted for the significant decline in PM2.5 over the study period (-0.35 μg/m³/yr or -4.24%/yr). This work shows the importance of long-term monitoring in assessing the unique contributions and temporal changes of industrialization on air quality in Ontario and similarly affected locations
Infection of wild-caught wood mice (Apodemus sylvaticus) and yellow-necked mice (A. flavicollis) with tick-borne encephalitis virus.
No full text
EURL-Salmonella ringonderzoek typering 2022
No full textSinds 1992 zijn de Nationale Referentie Laboratoria (NRL’s) van de lidstaten van de Europese Unie verplicht om elk jaar hun kwaliteit te laten toetsen met zogeheten ringonderzoeken. Een van de ringonderzoeken is de typering van Salmonella-bacteriën. In 2022 scoorden alle NRL’s van de 27 EU(European Union )-lidstaten goed bij deze kwaliteitscontrole op typering van Salmonella. Twee laboratoria hadden hiervoor een herkansing nodig. Als groep konden de deelnemende laboratoria aan 98 procent van de geteste stammen de juiste naam geven. De laboratoria zijn verplicht om Salmonella met een standaardmethode te typeren (serotypering). Daarnaast mochten zij in 2022 zelf aangeven of ze extra typeringen op DNA(deoxyribonucleic acid)-niveau wilden doen, bijvoorbeeld met Whole Genome Sequencing (WGS(whole genome sequencing)). Deze preciezere typering kan soms nodig zijn om de bron van een besmetting op te sporen. Voor de kwaliteitstoetsen wijst elke lidstaat een laboratorium aan, het Nationale Referentie Laboratorium (NRL). Dit NRL is namens dat land verantwoordelijk om Salmonella in monsters van levensmiddelen of dieren aan te tonen en te typeren. Om te controleren of de laboratoria hun werk goed doen, moeten zij onder andere twintig Salmonella-stammen de juiste naam kunnen geven. Soms doen er ook NRL’s van landen buiten de EU vrijwillig aan mee. In 2022 waren dat er zeven: het Verenigd Koninkrijk, de EU (potentiële) kandidaat-lidstaten Kosovo, Moldavië, en Turkije en de European Free Trade Association (EFTA) landen IJsland, Noorwegen en Zwitserland. Het Europese Unie Referentie Laboratorium voor Salmonella (EURL-Salmonella) organiseert het jaarlijkse ringonderzoek Salmonella-typering. Dit laboratorium is gevestigd bij het RIVM in Nederland.Since 1992, National Reference Laboratories (NRLs) of European Union (EU) Member States have been obliged to participate in annual quality control ‘Proficiency’ Tests (PTs). One of the PTs is on typing of Salmonella bacteria. The NRLs of all 27 EU Member States performed well in this 2022 quality control test on Salmonella typing. Two laboratories were found to require a follow-up study after the initial test. Overall, the participating laboratories were able to assign the correct name to 98% of the strains tested. Laboratories are obliged to type Salmonella with the reference method (serotyping). In 2022, they could also perform additional typing at the DNA level, for example by using Whole Genome Sequencing (WGS). More detailed DNA typing methods are sometimes needed to trace the source of a contamination. Each Member State designates a specific laboratory within their national boundaries to be responsible for the detection and identification of Salmonella in animals and/or food products. These laboratories are referred to as the National Reference Laboratories (NRLs). The performance of these NRLs in Salmonella typing is assessed annually by testing their ability to correctly identify 20 Salmonella strains. NRLs from countries outside the EU occasionally participate in these tests on a voluntary basis. Seven countries took part in 2022: the United Kingdom, the (potential) EU candidate countries Kosovo, Moldova, and Türkiye as well as the European Free Trade Association (EFTA) countries Iceland, Norway and Switzerland. The annual Proficiency Test on Salmonella typing is organised by the European Union Reference Laboratory for Salmonella (EURL-Salmonella). The EURL-Salmonella is located at the National Institute for Public Health and the Environment (RIVM) in the Netherlands