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.

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    On the role of vaccine dose and antigenic distance in the transmission dynamics of Highly Pathogenic Avian Influenza (HPAI) H5N1 virus and its selected mutants in vaccinated animals
    Sitaras, Ioannis - \ 2017
    Wageningen University. Promotor(en): M.C.M. Jong, co-promotor(en): B. Peeters. - Wageningen : Wageningen University - ISBN 9789463438063 - 209
    avian influenza viruses - avian influenza - disease transmission - vaccines - vaccination - dosage - antigenic variation - mutants - mutations - immunity - vaccine development - virology - epidemiology - aviaire influenzavirussen - aviaire influenza - ziekteoverdracht - vaccins - vaccinatie - dosering - antigene variatie - mutanten - mutaties - immuniteit - vaccinontwikkeling - virologie - epidemiologie

    Influenza virus infections can cause high morbidity and mortality rates among animals and humans, and result in staggering direct and indirect financial losses amounting to billions of US dollars. Ever since it emerged in 1996 in Guangdong province, People’s Republic of China, one particular highly pathogenic avian influenza (HPAI) H5N1 virus has spread globally, and is responsible for massive losses of poultry, as well as human infections. For these reasons, HPAI H5N1 is considered as one of the viruses possible to cause a future influenza pandemic.

    One of the main reasons why influenza is a recurring problem is its ability to constantly evolve through the selection of mutants that are able to avoid immunity (be it natural or acquired). Due to the accumulation of mutations during genome replication, diverse/variant influenza genome sequences co-exist in a virus pool (quasispecies). These sequences can contain mutations that are able to confer selective advantages to the influenza virus given the opportunity. As a consequence, whenever a situation arises that places the virus under any type of pressure that the dominant virus sequence cannot cope with (i.e. immune pressure, selective receptor binding, etc.), the virus with the genome sequence that allows it to better adapt to that particular pressure becomes selected and takes over.

    Because of the influenza virus’s high rate of mutations, a global surveillance network is in place to monitor changes in circulating strains among humans that would warrant an update of the vaccines used. For human influenza strains, vaccines are updated frequently (every one or two years) and a similar situation holds true for racehorse vaccination. For avian influenza vaccination, however, the situation is different. In most countries, vaccination against avian influenza is not used, and in the countries where vaccines are used (either as routine or emergency measures), they are not updated as frequently as human vaccines are. In addition, in many instances vaccination against avian influenza viruses has met with some spectacular failures, since it failed to produce a level of immunity that would protect against circulating field strains. These vaccination failures have often been attributed to the fact that without constant vaccine updating (as is done for human influenza), the vaccines used are not able to keep up with continuously evolving antigenic variants selected in the field, and thus to protect poultry against them. In addition, since it is known that immune pressure resulting from vaccination can be a driving force in the evolution of influenza viruses and the selection of immune-escape mutants, there is a school of thought that posits that vaccination against avian influenza is not only a very expensive affair (especially if vaccines need to be frequently updated), but can also lead to selection of mutants that are able to avoid vaccination-induced immunity.

    The research reported in this thesis started with addressing the gaps in the knowledge regarding the role of vaccination-induced immunity in the selection of immune-escape mutants of HPAI H5N1, and if there is a way for vaccines to still be able to protect against antigenically-distant variants of the vaccine seed strain, without the need for frequent vaccine updates.

    Our first step in studying influenza virus evolution and selection of immune-escape mutants was to investigate how antigenic pressure may drive the selection of such mutants, and what the effect of the selected mutations on the pathogenicity and transmissibility of the mutants may be. Although there exist a variety of methods to select for influenza virus mutations (i.e. monoclonal antibodies, site-directed mutagenesis, reverse genetics, etc.), none of them is representative of selection as it happens in a vaccinated animal. In Chapter 2, we discuss in detail a laboratory-based system we have developed, in which immune-escape mutants are selected using homologous polyclonal chicken sera, similar to how they are selected in the field due to vaccination- induced immune pressure. We find that selection takes place early on, and additional mutations are selected when immune pressure is increased. Antigenic distances between the selected mutants and their parent strains are also increased throughout the selection process, but not in a linear fashion. Our selection system proved to be robust and replicable, and to be representative of selection in the field, since the mutations we selected for are also found in naturally-selected field isolates, and the antigenic distances between our selected mutants and their parent strains are similar to antigenic distances between vaccine strains and field isolates.

    We continued our research by addressing the roles played by vaccine dose (and resulting immunity) and antigenic distance between vaccine and challenge strains, in the transmission of HPAI H5N1 viruses, by employing transmission experiments using vaccinated chickens (Chapter 3). To our surprise, we found that the effect of antigenic distances between vaccine and challenge strains on transmission is very small compared to the effect of vaccine dose. We then quantified, for the first time, the minimum level of immunity and minimum percentage of the vaccinated population exhibiting said immunity, in order for vaccines to be able to protect against transmission even of strains that are antigenically distant to the vaccine seed strain. Transmission of such strains in well-vaccinated populations would allow for a scenario where vaccination- induced immunity may drive the selection of immune-escape mutants. Our results show that in order for vaccines to prevent transmission of antigenically distant strains (such as the ones resulting from selection due to immune pressure), the threshold level of immunity against these strains should be ≥23 haemagglutination inhibition units (HIU), in at least 86.5% of the vaccinated population. This level of immunity can be estimated by knowing the antigenic distance between the vaccine and challenge (field) strain, and the HI titre against the vaccine strain, which would then allow the approximate level of immunity against the field strain to be deduced. For example, assuming the HI titre against a vaccine strain is 210 HIU, and the distance with the challenge (field) strain is 24 HIU, according to our results the vaccine should be able to protect against the challenge strain, because the difference in HI titres should be around 26 HIU (i.e. above 23 HIU). These results, taken together with our previous work on selection of mutants, where we showed that the antigenic distances between our mutants and their parent strains are representative of distances found in the field, point to the fact that it is unlikely that vaccination-induced immunity can lead to selection of mutants able to escape it, given that a threshold level of immunity in a minimum percentage of the vaccinated population is achieved. As a consequence, we believe that constant vaccine updating may not be necessary for avian influenza viruses, as long as a threshold level of immunity is maintained. This makes vaccination a more attractive control measure, both from a health perspective and a financial one, than just applying biosecurity measures.

    To examine the effect the mutations in the haemagglutinin protein of our selected mutants may have in their transmission among chickens vaccinated with the parent strain, we used reverse genetics techniques to insert the HA gene of our most antigenically distant mutant into the parent strain backbone (Chapter 4). We vaccinated animals with a sub-optimal dose of vaccine, and we concluded that the mutations we selected for did not allow the mutant to avoid even low levels of immunity, such as the ones resulting from a sub-optimal vaccine dose (which resembles a poor field vaccination scenario). At the same time, the HA mutations we selected for did not appear to have a negative effect either on the pathogenicity of the mutant, or its ability to transmit to unvaccinated animals, since both parameters were comparable to the parent strain.

    Finally, we studied the role inter-animal variation in immunity – as measured by HI titres – has in the accuracy of antigenic cartography calculations (Chapter 5). We found that using sera from more than one animal significantly increased the accuracy of antigenic distance calculations, since it takes into account individual differences in immune responses to vaccination, an inevitable phenomenon documented in both humans and animals. In addition, we increased the accuracy of antigenic maps by avoiding the use of dimension-reducing algorithms as is currently done. By not reducing the dimensionality of virus positioning in space, our maps retain the original geometry between strains or sera, leading to more accurate positioning (Chapters 2 and 5). We hope that improving the accuracy of antigenic cartography can lead to a more precise surveillance of influenza evolution and better informed decisions regarding the need to update vaccines.

    Taken collectively, our results can improve field vaccination outcomes, since they provide guidelines on how to increase vaccination efficiency in stopping transmission of even antigenically-distant strains. In addition, our method for selecting for immune- escape mutants can be a valuable addition to research on influenza virus evolution. Moreover, policy making decisions regarding vaccination against any type of influenza can also benefit from our improvement on antigenic cartography accuracy, saving unnecessary costs in vaccine updating, and reducing morbidity and mortality of both animals and humans.

    Risicofactoren voor introductie van laag-pathogeen aviare influenza virus op legpluimveebedrijven met vrije uitloop in Nederland
    Goot, J.A. van der; Elbers, A.R.W. ; Bouwstra, R.J. ; Fabri, T. ; Wijhe-Kiezebrink, M.C. van; Niekerk, T.G.C.M. van - \ 2015
    Lelystad : Central Veterinary Institute, onderdeel van Wageningen UR (CVI rapport / Centraal Veterinair Instituut 15/CVI0078) - 15
    pluimvee - gevalsanalyse - pluimveeziekten - pluimveehouderij - dierenwelzijn - uitloop - huisvesting van kippen - aviaire influenzavirussen - eenden - watervogels - risicofactoren - nederland - poultry - case studies - poultry diseases - poultry farming - animal welfare - outdoor run - chicken housing - avian influenza viruses - ducks - waterfowl - risk factors - netherlands
    Door middel van een case-control studie is onderzoek gedaan naar veronderstelde risicofactoren voor introductie van laag-pathogene aviaire influenza (LPAI) virus op pluimveelegbedrijven met vrije uitloop. Onder een LPAI virus werd in dit onderzoek verstaan: een aviair influenza virus van elk subtype (H1 tm H16), met uitzondering van de hoog pathogene aviaire influenza (HPAI) virussen. Veertig bedrijven met een LPAI virus introductie in het verleden (cases) zijn vergeleken met 81 bedrijven waar geen introductie heeft plaats gevonden (controls) om te onderzoeken of potentiële risicofactoren voor een besmetting met een LPAI virus geïdentificeerd kunnen worden. Vragen over aanwezigheid van potentiële risicofactoren zijn door middel van enquêtes voorgelegd aan de pluimveehouders.
    Vogelgriepvirus kwam aanvliegen uit Azië
    Sikkema, A. ; Bouwstra, R.J. - \ 2014
    Resource: weekblad voor Wageningen UR 9 (2014)8. - ISSN 1874-3625 - p. 8 - 8.
    aviaire influenza - aviaire influenzavirussen - besmetting - pluimveehouderij - pluimvee - diergezondheid - dierenwelzijn - ziekteoverdracht - dierlijke productie - avian influenza - avian influenza viruses - contamination - poultry farming - poultry - animal health - animal welfare - disease transmission - animal production
    CVI acht besmetting via trekvogels 'waarschijnlijk.' Het virus komt oorspronkelijk uit China.
    Mechanisms of Avian Influenza virus transmission between farms: combining data collection and mathematical modelling
    Ssematimba, A. - \ 2013
    Wageningen University. Promotor(en): Mart de Jong, co-promotor(en): Thomas Hagenaars. - S.l. : s.n. - ISBN 9789461734549 - 148
    aviaire influenzavirussen - ziekteoverdracht - pluimveehouderij - wiskundige modellen - epidemiologie - diergeneeskunde - nederland - avian influenza viruses - disease transmission - poultry farming - mathematical models - epidemiology - veterinary science - netherlands

    The lack of sufficient knowledge on the mechanisms of between-farm spread of livestock diseases hampers the development of much needed effective and fast control strategies. Some of the mechanisms responsible for pathogen spread can be deduced from epidemic tracing reports and literature while others can only be hypothesized from findings of studies on daily farm practices throughout the production round. For outbreaks without known/traced transmission routes, the concept of ‘neighbourhood’ infection is often adopted. This concept was founded based on the distance-dependence of the transmission risk with geographical proximity to an infectious farm being the key determinant of risk. Mathematical modelling plays an important role in obtaining quantitative insights into the contributions of the different mechanisms to disease spread. This can be by ranking the contributions of the individual transmission routes and/or obtaining a generic distance-dependent transmission risk. The models can guide the design of control strategies by providing a means to assess the efficacy of intervention strategies. In this thesis, modelling was used to assess the contributions of the wind-borne route and the other (traced) between-farm contacts to the transmission of highly pathogenic avian influenza during an epidemic in the Netherlands in 2003. It was found that these two routes together could only explain approximately 31% of the infections/cases. Visits by epidemic control teams were the least risky indicating the effectiveness of their biosecurity protocols in preventing transmission. New data on day-to-day farm practices and farmer opinion was collected in an attempt to generate hypotheses on transmission pathways and mechanisms that were yet to be appreciated. Indeed relevant unappreciated practices were found. They include irregularities in compliance to biosecurity as well as a broad category of neighbourhood-related risks. A new modelling approach to study neighbourhood transmission was developed guided by indirect transmission experiments. It involves the approximation of the pathogen dispersal process by a diffusive transport mechanism. Applying this diffusion model to the outbreak data of 2003, it was found that assuming delayed transmission, as opposed to instantaneous transmission, is an important phenomenon to be considered when modelling disease spread between locations. This modelling approach has the added advantage of availing an opportunity to assess the performance of intervention strategies without detailed mechanism-specific information.

    Vogelgriep ontrafeld : resultaten FES-AI onderzoeksprogramma
    Luijkx, D.L.M. ; Scholtens, B. ; Nijland, H.R. - \ 2012
    Lelystad : CVI - ISBN 9789461734907 - 62
    aviaire influenza - aviaire influenzavirussen - vogels - pluimveehouderij - epidemieën - dierziektepreventie - ziektebestrijding - vaccinatie - diagnostiek - virologie - nederland - avian influenza - avian influenza viruses - birds - poultry farming - epidemics - animal disease prevention - disease control - vaccination - diagnostics - virology - netherlands
    Vogelgriep en mensengriep zijn nauwe verwanten: beide worden meestal veroorzaakt door zogeheten Influenza-A-virussen. Zo'n griepvirus is een mini-kikkertje van hooguit honderd nanometer (0,0001 milimeter) doorsnede met eiwituitstulpingen aan de buitenkant. Daarmee klampt het virusbolletje zich vast aan de cellen van zijn gastheer. Die hechting heeft het nodig om de cel te infecteren en zichzelf daarna te kunnen vermenigvuldigen. Dit boekje heeft de vogelgriepuitbraak van 2003 in Nederland als startpunt. Welke dilemma's deden zich toen voor en welke bestrijdingsmogelijkheden waren er voorhanden? Vanwege de twijfels, vragen en onzekerheden werd het FES-AI onderzoeksprogramma in het leven geroepen. Het FES-AI programma is opgedeeld in 7 verschillende kennisvelden. Voor de samenstelling van dit boekje is gesproken met de onderzoekleiders, die het onderzoek vorm hebben gegeven.
    The role of Mallard (Anas platyrhynchos) in the spread of avian influenza: genomics, population genetics, and flyways
    Kraus, R.H.S. - \ 2011
    Wageningen University. Promotor(en): Herbert Prins; Ron Ydenberg, co-promotor(en): Pim van Hooft. - [S.l.] : S.n. - ISBN 9789461730282 - 143
    aviaire influenzavirussen - aviaire influenza - anas platyrhynchos - ziekteoverdracht - vogeltrek - genomica - populatiegenetica - evolutionaire genetica - zoögeografie - bioveiligheid - ziekteoverzichten - epidemiologie - avian influenza viruses - avian influenza - anas platyrhynchos - disease transmission - bird migration - genomics - population genetics - evolutionary genetics - zoogeography - biosafety - disease surveys - epidemiology

    Birds, in particular poultry and ducks, are a source of many infectious diseases, such as those caused by influenza viruses. These viruses are a threat not only to the birds themselves but also to poultry farming and human health, as forms that can infect humans are known to have evolved. It is believed that migratory birds in general play an important role in the global spread of avian influenza (AI). However, it is still debated how large this role precisely is and whether other modes of spread may be more important. The mallard (Anas platyrhynchos) is the world’s most abundant and well-studied waterfowl species. Besides being an important game and agricultural species, it is also a flagship species in wetland conservation and restoration. Waterfowl (Anseriformes: Anatidae) and especially ducks currently are the focal bird group in long distance dispersal of Avian Influenza in the wild, and the mallard has been identified as the most likely species to transport this virus.

    In my thesis I report aspects of the biology of this important host species of AI by molecular ecological means. As molecular marker system I established a genome-wide set of more than 100,000 SNPs of which I developed a subset of 384 SNPs into an assay to genotype about 1,000 ducks. This subset was employed to study the evolutionary history and speciation processes in the Anas genus. Further investigations into the world-wide mallard population structure on a species level were based not only on this set of 384 SNPs but also on mitochondrial DNA sequences. Last but not last, I investigated an option of AI sampling and detection from duck faeces by technology that is safe from a biohazard perspective, and solves transportation issues related to cold chains.

    The main results of my thesis include the development of a generally applicable improved analysis pipeline to develop genome-wide SNP sets for non-model organisms. Further, my results show that, from a migration system perspective, mallard flyways/populations can hardly be delineated from a biological point of view. Detailed phylogenetic, population genetic and coalescent analyses of a data set of samples spanning the whole northern hemisphere leads me to conclude that the only firm population boundaries that I can draw are between Eurasia and North America, within which panmixia is almost achieved. Mallards’ and other Anas-ducks’ whole continental to global distribution brings them together in sympatry. I can show that a combination of sympatric distribution, conflicting genetically determined and learned mate recognition mechanisms, and genomic compatibility between species helps to explain the long-standing puzzle of waterfowl hybridisation and introgression of genes from one duck species into another. Besides obvious management implications I propose that this fact can be part of the explanation why ducks are so well adaptable and successful, as well as why they show extraordinary abilities to withstand AI infections, or its consequences for health status.

    Avian influenza and migratory birds : a spatial - ecological perspective
    Si, Y. - \ 2011
    University of Twente. Promotor(en): Andrew Skidmore; Herbert Prins; T. Wang. - Enschede : University of Twente Faculty of Geo-Information and Earth Observation ITC - ISBN 9789061643081 - 129
    aviaire influenzavirussen - watervogels - vogeltrek - ruimtelijke ecologie - virologie - epidemiologie - milieufactoren - avian influenza viruses - waterfowl - bird migration - spatial ecology - virology - epidemiology - environmental factors
    Control of Highly Pathogenic Avian Influenza; Epidemiological and economic aspects
    Backer, J.A. ; Bergevoet, R.H.M. ; Fischer, E.A.J. ; Nodelijk, G. ; Bosman, K.J. ; Saatkamp, H.W. ; Roermund, H.J.W. van - \ 2011
    Den Haag : LEI, part of Wageningen UR (LEI report 2011-032) - ISBN 9789086155200 - 80
    aviaire influenzavirussen - pluimveeziekten - dierziekten - pluimvee - ziektebestrijding - vaccinatie - methodologie - efficiëntie - invloeden - epidemiologie - economische aspecten - economische situatie - economie - sociale economie - economische analyse - europese unie - nederland - avian influenza viruses - poultry diseases - animal diseases - poultry - disease control - vaccination - methodology - efficiency - influences - epidemiology - economic aspects - economic situation - economics - socioeconomics - economic analysis - european union - netherlands
    Epidemieën van hoog pathogene aviaire influenza (HPAI) kunnen een grote invloed hebben op het dierenwelzijn, de pluimveesector en, vanwege de zoönotische aard, ook op de volksgezondheid. Vanwege de vele mogelijke insleeproutes, reservoirs en mutaties in laag pathogene AI (LPAI) loopt het pluimvee in Nederland voortdurend het gevaar te worden besmet met HPAI. In geval van een uitbraak moeten de besmette boerderijen worden geruimd, moet het transport worden gereguleerd, moeten er beschermings- en toezichtsgebieden worden opgezet en moeten gevaarlijke contacten worden opgespoord, dit alles volgens de vereisten van de EU. Er kunnen ook bestrijdingsmaatregelen worden genomen om de blootgestelde bedrijfsdichtheid in het getroffen gebied te verkleinen door preventief ruimen of vaccineren. Net zoals in 2003, kan een nieuwe HPAI epidemie grote gevolgen hebben voor de pluimveesector. Het bestrijden van aangifteplichtige ziektes zoals AI door grootschalig preventief ruimen, wordt maatschappelijk steeds minder geaccepteerd, en de roep om alternatieve bestrijdingsmaatregelen zoals vaccinatie wordt steeds luider. Dit onderzoek ondersteunt het besluitvormingsproces.
    Onderzoek naar ganzentrek en het voorkomen van vogelgriep
    Ebbinge, B.S. ; Kleijn, D. ; Muskens, G.J.D.M. ; Polderdijk, C.A. - \ 2010
    Wageningen : Alterra (Alterra-rapport 2055) - 112
    ganzen - migratie - monitoring - aviaire influenzavirussen - jagen - merken - vogels - veldwerk - nederland - geese - migration - monitoring - avian influenza viruses - hunting - marking - birds - field work - netherlands
    Het langlopende ganzenvang- en merkprogramma dat Alterra in nauwe samenwerking met de Nederlandse Vereniging van Ganzenvangers al sinds 1954 uitvoert, is als monitoringsprogramma ingezet bij de analyse en interpretatie van de acute vraag of ganzen vogelgriep kunnen overbrengen over grote afstanden. Dankzij een internationaal netwerk van vrijwillige vogelwaarnemers, die hun waarnemingen van gemerkte ganzen via een speciale website kunnen doorgeven, wordt belangrijke informatie verkregen over de trekroutes van wilde ganzen. Tevens levert dit programma belangrijke gegevens over de jaarlijkse overlevingskans van ganzen en in hoeverre die door jacht wordt beïnvloed. Met deze informatie kunnen populatiemodellen getoetst en verbeterd worden, die voor het beheer van de sterk in aantal toegenomen ganzenpopulaties van belang zijn.
    Sustained effects of early-life oral colistin treatment on immune reactivity to intratracheally administered LPS and HuSA in chicken
    Lammers, A. ; Zutphen, L.J.W. van; Vries Reilingh, G. de; Parmentier, H.K. - \ 2010
    In: Proceeding of the 11th Avian Immunology Research Group Conference, Budapest, Hungary, 7-10 October 2010. - Budapest, Hungary : Diamond Congress LTd. - ISBN 9789638801920 - p. 51 - 51.
    vogels - immunologie - immuniteit - b lymfocyten - interferon - receptoren - aviaire influenzavirussen - cytokinen - vaccinatie - immunogenetica - birds - immunology - immunity - b lymphocytes - interferon - receptors - avian influenza viruses - cytokines - vaccination - immunogenetics
    Food risks and consumer trust : European governance of Avian influenza
    Krom, M.P.M.M. de - \ 2010
    Wageningen University. Promotor(en): Arthur Mol, co-promotor(en): Peter Oosterveer. - [S.l.] : S.n. - ISBN 9789085856986 - 160
    voedselveiligheid - aviaire influenzavirussen - consumentengedrag - europa - risicobeheersing - food safety - avian influenza viruses - consumer behaviour - europe - risk management
    During the 1990s, many European countries faced one or more food crises, such as bovine spongiform encephalopathy (BSE), E. coli, dioxin residues, and foot-and-mouth disease. These crises were marked by a growing public recognition of food-related risks and the changing nature of these risks, and tended to undermine citizen-consumer trust in the practices and institutions that managed food safety. To restore and retain trust in food throughout Europe, the European food policy framework was substantially renewed at the turn of the century. Conventional food governance was the domain of scientific experts, state agents and actors higher in the food supply chain, who decided on policy measures based on scientific data, and subsequently conveyed them to the general public. In the renewed framework for governing food, other social actors, including (individual and organised) citizen-consumers, were to be more actively involved through innovative roles.
    While this innovative position for citizen-consumers represents a definite discursive shift, it remains rather elusive how citizen-consumers should be included in food risk governance practices, and what effects such inclusion has on consumer trust. This study aims to further the understanding of whether and how citizen-consumer involvement in European food risk governance (re)establishes trust in the handling of food risks. It investigates consumer involvement within the conventional policy institutions (at the EU and Member State levels), as well as outside of these institutions (at shopping floors and in mass-media). The study focuses empirically on a major risk to Europe that emerged after the renewed policy framework had largely been implemented: highly pathogenic avian influenza H5N1.
    In August 2005, this avian influenza virus strain entered European public arenas as the next food and agricultural risk. As the virus was detected close to Europe, questions arose whether measures were required to protect human health and secure European food supply. Chapter 2 analyses the public debates on the characteristics of the risk and on the interventions needed. The mass media in two EU Member States, the UK and the Netherlands, were studied for this purpose. With the help of qualitative analysis the debates were analysed as they unfolded in selected national newspapers. Arguing that risks are socially mediated realities, this chapter discusses how struggles on risk definitions relate to different policy decisions. Moreover, it analyses how these political dynamics are informed by the involvement of state, market, science, and civil society actors, and discerns their implications for the functioning of the EU food governance framework.
    Chapter 3 explores consumer perspectives on food safety governance by expounding the results of an explorative study among Dutch consumers. Moving away from the ‘knowledge deficit’ model, which entails that consumers should be better educated to avoid ‘irrational’ responses, we investigate what consumers consider at the place and time they actually have to deal with food risks. To give ample room for the construction of contextual knowledge, consumers of poultry meat were questioned at various retailers by applying a qualitative interviewing method. From this research, it is concluded that multiple consumer rationalities about food safety governance exist. As a consequence of the existence of these multiple consumer rationalities, a differentiated governance approach to restore or retain consumer confidence is more likely to be pertinent than a ‘one-size-fits-all’ approach.
    Chapter 4 starts from the observation that, irrespective of the major food crises that occurred during the 2000s, consumer trust in food seems to remain high in Western Europe. Information provision to consumers on food risks is a central strategy of the EU, its Member States and private food providers to build food trust among consumers. But can the interpretation of such information by consumers explain these high levels of trust? Following recent outbreaks of avian influenza in the UK, this paper investigates the constitution of food trust among UK poultry consumers by focusing on the place where relevant consumer decisions are made: the shopping floor. In-store qualitative interviews with consumers of a variety of poultry products at different shops are used to reveal the role of information in constructing trust. It is concluded that besides on knowledge inducted from information provided, trust depends as much on consumer strategies to handle non-knowing of food risks. Three main forms of trust relations are distinguished, which together result in high levels of consumer trust at a system level.
    Chapter 5 studies the institutional incorporation of social interests and values in EU and Member State food risk governance. The study is based on qualitative analyses of key official publications and press releases from Member State and EU level bodies, as well as from scientists, NGOs and food supply chain actors. These analyses are combined with 40 in-depth interviews with relevant food system actors. The chapter reviews how and which social interests and values are incorporated in food risk governance in the Netherlands, France and the UK, and at the EU level. It concludes that predominantly through state-level political (and to a lesser extent: scientific) domains social interests and values were articulated on the EU agenda, while at the EU level food risk governance remained principally justified on the basis of scientific evidence. The chapter finishes with discerning the effects of this inclusion of social interest and values on public trust and the functioning of the internal market.
    The sixth and final chapter draws conclusions on the changing positions of, and relations between, scientists, policy makers, market actors and citizen-consumers. First, while natural scientists have lost their position as the a priori trustworthy source of risk information, they still maintain a central position in legitimating risk definitions. Yet, in this position scientists have become more transparent than in the past concerning their internal disagreements, and are (more overtly) incorporating wider social, economic and political arguments in their policy advice. Herewith, these scientists become more susceptible to public contestation, and risk assessment opens up for non-scientific actors aiming to publicly legitimate their own perspectives. In essence, this changing public character of risk assessments entails the conflation of two previously segregated risk governance phases: those of risk assessment and communication. With such communication, citizen-consumers are ‘invited’ or even ‘forced’ to conduct micro-level assessments and judgements of conflicting risk characterisations.
    Second, due to the dissolution of science as the uncontested source of risk characterisation, risk managers can no longer assume that they can legitimate their decisions by referring to scientific risk assessments, and the cost-benefit analyses based on them. Instead, policy makers are urged to base decisions also (more explicitly) on wider social interests and values and legitimate their handling of risks in view of scientific non-knowing. This is especially the case when risk knowledge bases are subject to public contestation, and when wider social perspectives on the appropriateness of different risk governance options diverge. In such situations, different risk perspectives may become dominant in different countries, as risks are mediated through different culturally-embedded and socially contextualised sense-making frames. Due to this differentiation, European Member States (re-)emerge as pivotal governance actors: while EU level food risk governance remains grounded in scientific-rational and technically-based justification which safeguards a minimum level of European policy harmonisation, more room has to be opened for the Member States to incorporate country-specific social interests and values in their decisions.
    Third, the possibilities for Member States to differentiate from a harmonised European food risk governance arrangement entailed increased room for private actors to become—legitimately—involved. By refusing to retail products whose characteristics were co-determined by Member State-specific measures, supermarkets became strongly involved in food risk governance—and were decisive in the success of such measures. Supermarkets legitimated their involvement with the argument of retaining their consumers’ trust in food.
    Fourth, citizen-consumers take on roles as micro-level assessors of conflicting risk characterisations, which ‘materialises’ in consumers’ co-governance of food risks through their consumption practices. With such consumer co-governance, consumption turns political, marking a partial shift of risk management practices towards places where consumers stand in ‘direct’ relation to the risk governors in the food supply and management systems: the shopping floors. On shopping floors, consumers differ in their perspectives on risks and on how to govern these. Hence, providing room for Member State-based differentiation in risk management does not necessarily mean one addresses all consumer rationalities, as for groups of consumers such management decisions may lack congruence with their perspectives and concerns.
    Moreover, political and policy institutions encounter difficulties to address in their risk management decisions the socio-contextual embeddedness of consumers, consumption practices and trust. Significant groups of consumers do not regard themselves merely as passive recipients of food products, information flows and governance outcomes. They are self-defined co-governors of the safety of food through their acts of buying food and relating to the relevant actor networks. Within these relations and co-constructions consumer trust is being built. As such, European and national policy institutions may contribute to the make-up of the constraining and enabling environment of the shopping floor, but these institutions cannot fully construct and determine consumer trust.
    Hence, we observed an increased involvement of (interests and values of) citizen-consumer in institutional risk assessment and management practices—particularly through Member State-level political domains. At the same time, risk assessment and management dynamics shift for an important part to contexts and practices outside of conventional, political and policy institutions: to the mass-media and shopping floors. Besides policy challenges, these dynamics entail opportunities for improving the European food risk governance process, which are set out in policy recommendations for different groups of governance actors. The study finishes with making some recommendations for further research.

    Trainingen tegen de vogelgriep
    Nell, A.J. ; Koch, G. - \ 2009
    Kennis Online 6 (2009)juni. - p. 10 - 10.
    vogels - aviaire influenzavirussen - aviaire influenza A-virussen - dierziekten - pluimveeziekten - birds - avian influenza viruses - avian influenza A viruses - animal diseases - poultry diseases
    Indonesië is wereldwijd het hardst getroffen door de vogelgriep. In een poging het virus de kop in te drukken, vroeg de Indonesische overheid in 2004 Nederland om hulp met de bestrijding. Sindsdien werken Wageningen International en het Centraal Veterinair Instituut (CVI) samen met GD Deventer en Universiteit Utrecht aan een strategie om de vogelpest op West-Java onder controle te krijgen
    Avian influenza: Use of recombinant DNA techniques in research and vaccine development
    Peeters, B.P.H. - \ 2008
    Tijdschrift voor Diergeneeskunde 133 (2008)22. - ISSN 0040-7453 - p. 956 - 958.
    aviaire influenzavirussen - genetische modificatie - recombinant dna - onderzoek - avian influenza viruses - genetic engineering - recombinant dna - research
    Informatie omtrent de stand van zaken betreffende het influenzavirusonderzoek
    Benodigde destructiecapaciteit bij de bestrijding van besmettelijke dierziekten in Nederland
    Bergevoet, R.H.M. ; Backer, J.A. ; Horne, P.L.M. van - \ 2008
    Den Haag : LEI (LEI rapport ) - 23
    veehouderij - dierziekten - vernietiging van dieren - destructie - afrikaanse varkenspest - aviaire influenzavirussen - mond- en klauwzeer - livestock farming - animal diseases - destruction of animals - destruction - african swine fever - avian influenza viruses - foot and mouth disease
    In deze notitie tracht men de omvang te bepalen van het aan te bieden destructiemateriaal op enig moment in de toekomst als gevolg van een dierziektebestrijding. Belangrijk is niet zozeer de totale hoeveelheid, maar de maximale hoeveelheid per week die moet worden verwerkt. Resultaten zijn geven voor Afrikaanse varkenspest, aviaire influenza en mond en klauwzeer
    Adviesaanvraag VWA : opheffing toelatingsverbod van pluimvee en postduiven
    Koch, G. ; Elbers, A.R.W. ; Rooij, E.M.A. van - \ 2008
    Wageningen : Centraal Veterinair Instituut - 29
    risicoschatting - postduiven - pluimvee - aviaire influenzavirussen - aviaire influenza A-virussen - risk assessment - racing pigeons - poultry - avian influenza viruses - avian influenza A viruses
    Deze adviesaanvraag van het VWA beoordeelt of het sinds 2003 bestaande verbod op het toelaten van buitenlands pluimvee en postduiven op Nederlands grondgebied voor tentoonstellingen, shows, wedstrijden en dergelijke kan worden opgeheven. Het verbod is ingesteld i.v.m. mogelijke insleep van hoog-pathogeen Aviaire Influenza (HPAI) subtype H5N1 via buitenlands pluimvee en postduiven.
    Gezondheid van biologische leghennen
    Fiks-van Niekerk, T.G.C.M. ; Bestman, M.W.P. ; Wagenaar, J.P. ; Krimpen, M.M. van; Mul, M.F. ; Kijlstra, A. ; Reimert, H.G.M. ; Reuvekamp, B.F.J. - \ 2008
    Lelystad : Animal Sciences Group (Boek / Animal Sciences Group nr. 5) - 80
    biologische landbouw - pluimveehouderij - hennen - diergezondheid - dierenwelzijn - vaccinatie - verenpikken - hennenvoeding - wormen - bacterieziekten - salmonella - escherichia coli - brachyspira - aviaire influenzavirussen - infectieus bronchitisvirus - voedselveiligheid - dioxinen - dierhouderij - pluimvee - organic farming - poultry farming - hens - animal health - animal welfare - vaccination - feather pecking - hen feeding - helminths - bacterial diseases - salmonella - escherichia coli - brachyspira - avian influenza viruses - infectious bronchitis virus - food safety - dioxins - animal husbandry - poultry
    Dit boekje bevat een bundeling van reeds eerder uitgegeven artikelen en brochures van ASG en LBI over gezondheid van biologische leghennen. Tevens zijn enkele nieuwe stukken toegevoegd over onderwerpen die voor de biologische leghennenhouderij van belang zijn.
    Ophokplicht en biologische hennen: stoffig op stok
    Kijlstra, A. ; Werf, J.T.N. van der - \ 2008
    pluimveehouderij - aviaire influenzavirussen - pluimveeziekten - agrarische bedrijfsvoering - biologische landbouw - dierenwelzijn - huisvesting, dieren - hokken - stof - dierziektepreventie - maatregelen - poultry farming - avian influenza viruses - poultry diseases - farm management - organic farming - animal welfare - animal housing - pens - dust - animal disease prevention - measures
    Ophokplicht is een noodoplossing, maar blijft waarschijnlijk een steeds terugkerende realiteit zolang de vogelgriep rondwaart onder trekvogels en inenting nog geen gemeengoed is. Vooral voor de biologische pluimveehouderij staat daarbij veel op het spel. Daarom brachten Wageningse onderzoekers meteen al in 2005 zo goed mogelijk de gevolgen in kaart die ophokken had voor biologische leghennen. Die vallen mee, al wordt het binnen vaak wel een zorgwekkend stoffige boel
    Methods for the enormous killing of poultry by animal illnesses a challenge: acceptable in certain concerns for nuisance and efficiency = Methoden voor het grootschalig doden van pluimvee voor dierziekte bestrijding: aanvaardbaar wat betreft ongerief en efficiëntie
    Gerritzen, M.A. - \ 2007
    Tijdschrift voor Diergeneeskunde 132 (2007)4. - ISSN 0040-7453 - p. 129 - 131.
    bio-ethiek - vernietiging van dieren - pluimveehouderij - ziektebestrijding - aviaire influenzavirussen - fumigatie - dierenwelzijn - aviaire influenza A-virussen - uitbraken (ziekten) - bezettingsdichtheid - pluimveebedrijf - pluimveeproducten - pluimveeziekten - ziektedistributie - aviciden - dierfysiologie - bioethics - destruction of animals - poultry farming - disease control - avian influenza viruses - fumigation - animal welfare - avian influenza A viruses - outbreaks - stocking density - poultry industry - poultry products - poultry diseases - disease distribution - avicides - animal physiology
    De productie van pluimveeproducten is in Nederland een belangrijke economische activiteit. Allen al in Nederland worden voor de productie van eieren en vlees jaarlijks driehonderd miljoen kippen gefokt en geslacht. De productie van deze pluimveeproducten is voornamelijk geconcentreerd op grote bedrijven die dicht bij elkaar liggen met veel dieren per vierkante meter, met als gevolg gebieden met een hoge pluimveedichtheid. Door deze hoge concentratie dieren in een beperkt gebied hebben uitbraken van besmettelijke dierziekten, zoals hoog pathogene aviaire influenza (HPAI), ernstige consequenties voor pluimvee, de pluimveehouders, en de gemeenschap
    Vogel(griep) vrij
    Geenen, P.L. ; Grabkowsky, B. - \ 2007
    De Pluimveehouderij januari (2007)38. - ISSN 0166-8250 - p. 16 - 17.
    pluimveehouderij - pluimvee - aviaire influenzavirussen - infectieziekten - poultry farming - poultry - avian influenza viruses - infectious diseases
    Hoe veilig is uw bedrijf eigenlijk voor vogelgriep? Europees onderzoek kan daar zicht op bieden. Het telkens terugkerende steekwoord is, en dat mag en zal niet verbazen, hygiëne
    De risico's van virusverspreiding in kaart gebracht met behulp van GIS-software
    Groot, N.E. - \ 2007
    Agro Informatica 20 (2007)1. - ISSN 0925-4455 - p. 19 - 22.
    aviaire influenzavirussen - ziektedistributie - ganzen - anser - migratie - geografische informatiesystemen - avian influenza viruses - disease distribution - geese - anser - migration - geographical information systems
    Een studie is gedaan naar de mogelijke verspreiding van het hoogpathogene vogelgriepvirus H5N1 door de kolgans (Anser albifrons albifrons) in Europa. Hierop voortbordurend wordt de modellering van de verspreiding van het vogelgriepvirus in Europa met GIS-software besproken
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