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Het RIVM heeft berekend wat het effect is van verschillende hoeveelheden ventilatie van binnenruimten op 'aerogene transmissie' van het coronavirus SARS-CoV-2. Aerogene transmissie betekent besmettingen met het virus via kleine druppels (aerosolen) die over een grotere afstand dan anderhalve meter en over langere tijd kunnen blijven zweven in de lucht. Ventileren helpt om aerogene transmissie te beperken. Bij ventileren wordt continu verse buitenlucht aan een ruimte toegevoerd waardoor de lucht in een binnenruimte wordt ververst. Vanwege een goed binnenklimaat moeten alle gebouwen in Nederland, waaronder woningen, aan de minimale ventilatie-eisen van het Bouwbesluit voldoen. Het blijkt dat ventilatie volgens de minimale eisen van het Bouwbesluit 2012 voor bestaande gebouwen de kans op aerogene transmissie flink verkleint in vergelijking met niet-ventileren. Nog meer ventileren maakt de kans nog kleiner, maar het effect daarvan is minder groot. Ventilatie neemt het risico op aerogene transmissie nooit helemaal weg. Ook bij heel veel ventilatie, waarbij de binnenlucht bijvoorbeeld elke 2 minuten helemaal wordt ververst, blijft een kans bestaan dat het virus op deze manier wordt overgedragen. Het RIVM heeft voor bepaalde publieke binnenruimtes berekend welk effect ventilatie naar verwachting heeft op het aantal mensen dat ziek wordt. Voorbeelden zijn een nachtclub, een kleine en een grote concertzaal, een klaslokaal, een kantoorruimte en een supermarkt. Ventilatie verkleint het verwachte aantal zieken het meest in de nachtclub en beide concertzalen. Het onderzoek geeft handvatten om beleidskeuzes te maken. Het is niet mogelijk om op basis van de resultaten aan te geven welk risico acceptabel is en wat een optimale hoeveelheid ventilatie is. Hiervoor zijn andere afwegingen nodig tussen aanvaardbare risico’s en eisen aan comfort, de kosten van aanschaf en onderhoud, en energiegebruik. Het is een beleidskeuze om te bepalen welk risico na deze afwegingen acceptabel wordt gevonden. Het gaat in dit onderzoek alleen om het risico op besmetting via aerogene transmissie. Het gaat niet om andere manieren waarop mensen besmet kunnen raken, zoals besmetting binnen anderhalve meter afstand (directe transmissie).

Background: Evidence for indoor airborne transmission of SARS-CoV-2 is accumulating. Objectives: We assessed of the risk of illness due to airborne SARS-CoV-2 particles from breathing, speaking, singing, coughing, and sneezing in indoor environments. Methods: A risk assessment model, AirCoV2, for exposure to SARS-CoV-2 particles in aerosol droplets was developed. Previously published data on droplets expelled by breathing, speaking, singing, coughing, and sneezing by an infected person were used as inputs. Scenarios encompassed virus concentration, exposure time, and ventilation. Newly collected data of virus RNA copies in mucus from patients are presented. Results: The expelled volume of aerosols was highest for a sneeze, followed by a cough, singing, speaking, and breathing. After 20 min of exposure, at 107 RNA copies/mL in mucus, all mean illness risks were largely estimated to be below 0.001, except for the “high” sneeze scenario. At virus concentrations above 108 RNA copies/mL, and after 2 h of exposure, in the high and “low” sneeze scenarios, the high cough scenario and the singing scenario, risks exceeded 0.01 and may become very high, whereas the low coughing scenario, the high and low speaking scenarios and the breathing scenario remained below 0.1. After 2 h of exposure, singing became the second highest risk scenario. One air exchange per hour reduced risk of illness by about a factor of 2. Six air exchanges per hour reduced risks of illness by a factor of 8–13 for the sneeze and cough scenarios and by a factor of 4–9 for the other scenarios. Discussion: The large variation in the volume of expelled aerosols is discussed. The model calculations indicated that SARS-CoV-2 transmission via aerosols outside of the 1.5-m social distancing norm can occur. Virus concentrations in aerosols and/or the amount of expelled aerosol droplets need to be high for substantial transmission via this route. AirCoV2 is made available as interactive computational tool. https://doi.org/10.1289/EHP7886

Acute hemorrhagic conjunctivitis (AHC) is a painful, contagious eye disease, with millions of cases in the last decades. Coxsackievirus A24 (CV-A24) was not originally associated with human disease, but in 1970 a pathogenic “variant” (CV-A24v) emerged, which is now the main cause of AHC. Initially, this variant circulated only in Southeast Asia, but it later spread worldwide, accounting for numerous AHC outbreaks and two pandemics. While both CV-A24 variant and nonvariant strains still circulate in humans, only variant strains cause AHC for reasons that are yet unknown. Since receptors are important determinants of viral tropism, we set out to map the CV-A24 receptor repertoire and establish whether changes in receptor preference have led to the increased pathogenicity and rapid spread of CV-A24v. Here, we identify ICAM-1 as an essential receptor for both AHC-causing and non-AHC strains. We provide a high-resolution cryo-EM structure of a virus–ICAM-1 complex, which revealed critical ICAM-1–binding residues. These data could help identify a possible conserved mode of receptor engagement among ICAM-1–binding enteroviruses and rhinoviruses. Moreover, we identify a single capsid substitution that has been adopted by all pandemic CV-A24v strains and we reveal that this adaptation enhances the capacity of CV-A24v to bind sialic acid. Our data elucidate the CV-A24v receptor repertoire and point to a role of enhanced receptor engagement in the adaptation to the eye, possibly enabling pandemic spread.

Analyse poliomonsters na lozingsincident Op 2 september 2014 heeft het bedrijf GlaxoSmithKline (GSK), dat vaccins produceert, in België door een menselijke fout 45 liter geconcentreerd poliovirus op het riool geloosd. Via de nabijgelegen rioolwaterzuivering is dit water onder andere in de rivier De Laan terechtgekomen, en vervolgens in de Westerschelde. Er is geen poliovirus aangetoond in de beschikbare monsters. Ook is het poliovirus niet in de onderzochte bevolking verspreid. Dit blijkt uit onderzoek van het door de WHO erkende referentielaboratorium voor polio van het RIVM. Het onderzoek hier verricht in opdracht van de WHO, omdat België niet over een laboratorium beschikt dat hiervoor geaccrediteerd is. De WHO streeft ernaar om polio uit te roeien. Het onderzoek is ingegeven door het ophanden zijnde oesterseizoen (begin oktober) en het hoge aantal nietgevaccineerde bewoners van sommige Zeeuwse gemeenten. Tussen 2 en 18 september zijn monsters bij de rioolwaterzuivering (rwzi) te Rosières verzameld door personeel van GSK en de KU Leuven. Ook zijn monsters van sediment uit de bezinkingsbak van deze rwzi en slibmonsters uit de rivier De Laan genomen. Verder zijn in enkele gemeenten met een lage vaccinatiegraad tussen 30 september en 7 november rioolwatermonsters verzameld. Daarnaast is berekend dat de lozing vanaf 20 september in de Westerschelde zou kunnen stromen. Aangezien schelpdieren zich voeden door water te filteren, kunnen aanwezige verontreinigingen, zoals poliovirussen, zich ophopen in hun maag-darmkanaal. Op 24 september en 3 en 28 oktober zijn mosselen verzameld in het oostelijke deel van de Westerschelde, daar waar de te verwachte concentratie poliovirussen het hoogst was.

Detection should enable containment of viral foodborne infections., Because secondary transmission masks the connection between sources and outbreaks, estimating the proportion of foodborne norovirus infections is difficult. We studied whether norovirus genotype frequency distributions (genotype profiles) can enhance detection of the sources of foodborne outbreaks. Control measures differ substantially; therefore, differentiating this transmission mode from person-borne or food handler–borne outbreaks is of public health interest. Comparison of bivalve mollusks collected during monitoring (n = 295) and outbreak surveillance strains (n = 2,858) showed 2 distinguishable genotype profiles in 1) human feces and 2) source-contaminated food and bivalve mollusks; genotypes I.2 and I.4 were more frequently detected in foodborne outbreaks. Overall, ≈21% of all outbreaks were foodborne; further analysis showed that 25% of the outbreaks reported as food handler–associated were probably caused by source contamination of the food.

The burden of diseases caused by food-borne pathogens remains largely unknown. Importantly data indicating trends in food-borne infectious intestinal disease is limited to a few industrialised countries, and even fewer pathogens. It has been predicted that the importance of diarrhoeal disease, mainly due to contaminated food and water, as a cause of death will decline worldwide. Evidence for such a downward trend is limited. This prediction presumes that improvements in the production and retail of microbiologically safe food will be sustained in the developed world and, moreover, will be rolled out to those countries of the developing world increasingly producing food for a global market. In this review evidence is presented to indicate that the microbiological safety of food remains a dynamic situation heavily influenced by multiple factors along the food chain from farm to fork. Sustaining food safety standards will depend on constant vigilance maintained by monitoring and surveillance but, with the rising importance of other food-related issues, such as food security, obesity and climate change, competition for resources in the future to enable this may be fierce. In addition the pathogen populations relevant to food safety are not static. Food is an excellent vehicle by which many pathogens (bacteria, viruses/prions and parasites) can reach an appropriate colonisation site in a new host. Although food production practices change, the well-recognised food-borne pathogens, such as Salmonella spp. and Escherichia coli, seem able to evolve to exploit novel opportunities, for example fresh produce, and even generate new public health challenges, for example antimicrobial resistance. In addition, previously unknown food-borne pathogens, many of which are zoonotic, are constantly emerging. Current understanding of the trends in food-borne diseases for bacterial, viral and parasitic pathogens has been reviewed. The bacterial pathogens are exemplified by those well-recognized by policy makers; i.e. Salmonella, Campylobacter, E. coli and Listeria monocytogenes. Antimicrobial resistance in several bacterial food-borne pathogens (Salmonella, Campylobacter, Shigella and Vibrio spp., methicillin resistant Staphylcoccus aureas, E. coli and Enterococci) has been discussed as a separate topic because of its relative importance to policy issues. Awareness and surveillance of viral food-borne pathogens is generally poor but emphasis is placed on Norovirus, Hepatitis A, rotaviruses and newly emerging viruses such as SARS. Many food-borne parasitic pathogens are known (for example Ascaris, Cryptosporidia and Trichinella) but few of these are effectively monitored in foods, livestock and wildlife and their epidemiology through the food-chain is poorly understood. The lessons learned and future challenges in each topic are debated. It is clear that one overall challenge is the generation and maintenance of constructive dialogue and collaboration between public health, veterinary and food safety experts, bringing together multidisciplinary skills and multi-pathogen expertise. Such collaboration is essential to monitor changing trends in the well-recognised diseases and detect emerging pathogens. It will also be necessary understand the multiple interactions these pathogens have with their environments during transmission along the food chain in order to develop effective prevention and control strategies.

In this experiment the effectiveness of a fotonovela for Dutch low-literates was assessed and underlying mechanisms that could account for possible persuasive effects were studied. The Entertainment Overcoming Resistance Model (EORM; Moyer-Gusé, 2008) served as a theoretical framework. The fotonovela that was used was a Dutch translation of the diabetes fotonovela ‘Sweet Temptations’ developed and tested in the US. Participants were 92 low-literates, randomly assigned to one of three groups: a group that read the fotonovela, a group that read a traditional diabetes brochure, and a control group that only answered questions about diabetes knowledge and behavioral intentions. Both the fotonovela and the traditional brochure produced more diabetes knowledge and stronger behavioral intentions than were measured in the control group. The fotonovela outperformed the traditional brochure in effects on diabetes knowledge. No support was found for propositions in the EORM concerning the role of mediators in the persuasive effects of processing a narrative message.

Viruses are the most common cause of infectious disease acquired in the indoor environment in hospitals, schools and households causing considerable impact on human health. Transmission of enteric and respiratory viruses is assumed to occur predominantly direct from person to person followed by indirect transmission through contaminated fomites/surfaces. The risk of infection resulting from transmission through contaminated surfaces depends on a number of factors, including the level of shedding of infective particles, their stability on surfaces and resistance to decontamination procedures, fractions transmitted per contact and the dose required for infection. Among the enteric viruses, human noroviruses (NoVs) and rotaviruses are most notorious for causing outbreaks of gastroenteritis within hospitals, nursing homes and cruise ships and are significant cause of hospitalization. Besides human NoV and rotavirus, other enteric viruses like enteroviruses and parechoviruses, and respiratory viruses like influenza and adenovirus may also be transmitted through contaminated surfaces.

International audience; Between mid-September and 19 October 2008, nine clusters of norovirus infection involving around 90 primary cases and over a hundred secondary cases were identified in patients from the Netherlands, Ireland, Italy and France, linked to pilgrimage to Lourdes, France.

Increased surveillance of pathogens may for strengthen the prevention and control of infectious diseases. Infectious diseases cause a considerable burden of disease the Netherlands. Detailed characterization of pathogens will yield insight in changes of the pathogen itself, in changes in transmission patterns, and in changes in virulence and resistance. Therefore it is necessary to determine which pathogens should be studied, to what level of detail, and how they should be collected. In this report , the bacteria, viruses and parasites that give the the greatest burden of disease or present the greatest risk for the public health have been described in a standardized way. Several pathogens emerge from this study for which an increase in collection and characterization is desirable. Examples are: 1) Human papillomavirus, to improve assessment of the potential vaccine efficacy. 2) Influenza virus, to better characterize resistance to antiviral drugs. 3) Bordetella pertusis (whooping cough), to detect population changes that can influence vaccine efficacy. 4) Meticillin-resistance Staphylococcus aureus (MRSA), to reduce delays in contact-source tracing and containment. The pathogen surveillance in the Netherlands will be intensified on basis of this report. This enhanced surveillance will be executed in close co-operation with the peripheral microbiological laboratories.

Purpose: previous studies have shown that the rat small intestinal cell line IEC-18 provides a size-selective barrier for paracellularly transported hydrophilic macromolecules. In order to determine the utility of IEC-18 cells as an in vitro model to screen the passive paracellular and transcellular components of the intestinal transport of nutrients and drugs, we have now examined the transport of GlySar (H+-coupled di/tripeptide carrier), O-methyl-D-glucose (glucose carrier), vincristine and rhodamine 123 (P-glycoprotein), and calcein and DNPSG (MRPs) and the bidirectional transport of paracellularly transported compounds. Transport of these compounds across the filter grown IEC-18 cells was compared with transport across the human colon carcinoma Caco-2 cells. Results: in IEC-18 cells, transepithelial transport of GlySar and methylglucose was as fast as the transport of mannitol, which is transported passively via the paracellular route. Whereas in Caco-2 cells, mannitol transport was much slower than the transport of GlySar and methylglucose. In contrast to Caco-2 cells, no H+-coupled transport of GlySar could be measured in IEC-18 cells. P-Glycoprotein-mediated transport was characterised in Caco-2 cells by an enhanced transport of vincristine and rhodamine 123 in the basolateral to apical direction and by the inhibition of this transport by verapamil. In IEC-18 cells, permeability of vincristine and rhodamine 123 was similar in both directions and verapamil had no effect on the transport of these compounds. Both IEC-18 and Caco-2 cells efflux the organic anions calcein and DNPSG to the apical and basolateral compartments, and this efflux could be inhibited by probenecid. Conclusions: in conclusion, no carrier-mediated transport of GlySar, methylglucose, vincristine and rhodamine 123 could be determined in IEC-18 cells in contrast to Caco-2 cells. However, both IEC-18 and Caco-2 cells showed MRP-mediated eflux system(s) in the apical and basolateral membrane. Monolayers of IEC-18 cells appear to be more suitable than monolayers of Caco-2 cells as an in vitro system to screen the passive component of the intestinal transport in a deconvoluted screening regimen, where passive transport is represented by the IEC-18 monolayer permeability and active transport is represented by monolayers of cells expressing the transport proteins heterologously. © 2002 Elsevier Science B.V. All rights reserved.