Staff Publications

Staff Publications

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

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

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

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

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    Editorial : Proceedings of the 2nd ISESSAH Conference 2018
    Raboisson, Didier ; Vosough Ahmadi, Bouda ; Peyre, Marisa ; Hogeveen, Henk ; Gunn, George John ; Rushton, Jonathan - \ 2020
    Frontiers in Veterinary Science 7 (2020). - ISSN 2297-1769
    biosecurity - economics - infectious diseases - ISESSAH - social sciences
    Counts of bovine monocyte subsets prior to calving are predictive for postpartum occurrence of mastitis and metritis
    Pomeroy, Brianna ; Sipka, Anja ; Hussen, Jamal ; Eger, Melanie ; Schukken, Ynte - \ 2017
    Cornell University
    medicine - cell biology - genetics - ecology - immunology - mathematical sciences - developmental biology - infectious diseases - computational biology
    The heightened susceptibility to infectious diseases in postpartum dairy cows is often attributed to immune dysfunction associated with the transition period. However, the cell populations involved in this immune dysfunction and the dynamics between those populations are not well defined. Monocytes play a crucial role in governing initial immune response in bacterial infections. Bovine monocytes are subdivided in classical (CD14+/CD16−), intermediate (CD14+/CD16+) and non-classical monocytes (CD14−/CD16+) with distinct phenotypic and functional differences. This study investigated the relationship of monocyte subsets counts in blood at 42 and 14 days prior to expected calving date to occurrence of metritis and mastitis within 2 weeks postpartum. In the enrolled prospective cohort of 27 German Holstein cows, housed at the Institute of Animal Nutrition of the Friedrich-Loeffler-Institute Braunschweig, Germany, n = 13 developed metritis and/or mastitis postpartum. A multivariable logistic regression was used to analyze the relationship between prepartum cell counts of monocyte subsets and neutrophils with postpartum disease. Our model revealed that higher counts of the two CD14+ monocyte subsets were predictive of disease. In contrast, higher numbers of the CD14− monocyte subset were negatively associated with disease. Interestingly, the neutrophil count, a common hallmark for inflammatory response, was not associated with the outcome variable at either time point. The results indicate that the number and composition of monocyte subsets before calving are related to the susceptibility to infectious disease within 2 weeks postpartum. Furthermore the oppositional effect of CD14+ and CD14− subsets strengthens the hypothesis that these subsets have different functional roles in the inflammatory response in dairy cows.
    Wat zijn de mogelijkheden om een leverbotinfectie van melkvee te voorkomen?
    Neijenhuis, Francesca ; Verwer, Cynthia ; Verkaik, Jan - \ 2017
    Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 1029) - 65
    leverbot - fascioliasis - melkvee - melkveehouderij - parasitosen - infectieziekten - dierlijke productie - dierenwelzijn - diergezondheid - biologische landbouw - liver flukes - fascioliasis - dairy cattle - dairy farming - parasitoses - infectious diseases - animal production - animal welfare - animal health - organic farming
    Infecties met leverbot zijn in toenemende mate een knelpunt in de diergezondheid van grazende (of vers gras gevoerde) herkauwers. Leverbotinfectie leidt tot ziekte met economische gevolgen en voor melkgevende dieren zijn geen anthelmintica vrij beschikbaar. In dit project is het leverbotinstrument ontwikkeld met als doel om veehouders inzicht en handelingsperspectief te geven ten aanzien van de leverbotsituatie op hun bedrijf. In dit rapport worden de resultaten weergegeven van het leverbotinstrument en een drietal preventieve maatregelen die zijn uitgeprobeerd.
    Estimating host genetic effects on susceptibility and infectivity to infectious diseases and their contribution to response to selection
    Anche, M.T. - \ 2016
    Wageningen University. Promotor(en): Mart de Jong, co-promotor(en): Piter Bijma. - Wageningen : Wageningen University - ISBN 9789462577442 - 185
    livestock - hosts - genetic effects - susceptibility - infectivity - infectious diseases - breeding value - heritability - epidemics - vee - gastheren (dieren, mensen, planten) - genetische effecten - vatbaarheid - infectiviteit - infectieziekten - fokwaarde - heritability - epidemieën

    Mahlet Teka Anche. (2016). Estimating host genetic effects on susceptibility and infectivity to infectious diseases and their contribution to response to selection. PhD thesis, Wageningen University, the Netherlands

    Genetic approaches aiming to reduce the prevalence of an infection in a population usually focus on improving host susceptibility to an infection. The prevalence of an infection, however, is also affected by the infectivity of individuals. Studies reported that there exists among host (genetic/phenotypic) variation in susceptibility and infectivity to infectious diseases. The effect of host genetic variation in susceptibility and infectivity on the prevalence and risk of an infection is usually measured by the value of the basic reproduction ratio, R0. R0 is an important epidemiological parameter that determines the risk and prevalence of an infection. It has a threshold value of 1, where major disease outbreak can occur when R0 > 1 and the disease will die out when R0 < 1. Due to this threshold property, genetic improvements aiming to reduce the prevalence of an infection should focus on reducing R0 to a value below 1. The overall aim of this thesis was to develop methodologies that allow us to investigate the genetic effects of host susceptibility and infectivity on the prevalence of an infection, which is measured by the value of R0. Moreover, we also aim to investigating the effect of relatedness among groupmates on the utilization of among host genetic variation in susceptibility and infectivity so as to reduce the prevalence of infectious diseases. The theory of direct-indirect genetic effects and epidemiological concepts were combined to develop methodologies. In addition, a simulation study was performed to validate the methodologies developed and examine the effect of relatedness on the utilization of genetic variation in susceptibility and infectivity. It was shown that an individual’s genetic effect on its susceptibility and infectivity affect the prevalence of an infection and that an individual’s breeding value for R0 can be defined as a function of its own allele frequencies for susceptibility and infectivity and of population average susceptibility and infectivity. Moreover, simulation results show that, not only an individual’s infectivity but also an individual’s susceptibility represents an indirect genetic effect on the disease status of individuals and on the prevalence of an infection in a population. It was shown that having related groupmates allows breeders to utilize the genetic variation in susceptibility and infectivity, so as to reduce the prevalence of an infection.

    GD-directeur Ynte Schukken reageert op suggesties: 'geen specifieke zorgen over diergezondheid op grote bedrijven' : groei vraagt meer aandacht voor infectieziekten
    Schukken, Ynte - \ 2016
    dairy cattle - dairy farming - animal health - farm size - infectious diseases - animal disease prevention

    Theoretisch is goed te verklaren dat infectieziekten vaker voorkomen als melkveebedrij ven groeien. Maar GD-directeur Ynte Schukken wil daarmee niet gezegd hebben dat besmettingen op grote bedrij ven voor meer problemen zouden zorgen

    Breeding against infectious diseases in animals
    Rashidi, H. - \ 2016
    Wageningen University. Promotor(en): Johan van Arendonk, co-promotor(en): Herman Mulder; P.K. Mathur. - Wageningen University - ISBN 9789462576452 - 179
    livestock - infectious diseases - animal breeding - selective breeding - disease resistance - tolerance - genetic variation - breeding value - genetic correlation - traits - genomics - animal genetics - vee - infectieziekten - dierveredeling - selectief fokken - ziekteresistentie - tolerantie - genetische variatie - fokwaarde - genetische correlatie - kenmerken - genomica - diergenetica

    Infectious diseases in farm animals are of major concern because of animal welfare, production costs, and public health. Farms undergo huge economic losses due to infectious disease. The costs of infections in farm animals are mainly due to production losses, treatment of infected animals, and disease control strategies. Control strategies, however, are not always successful. Selective breeding for the animals that can mount a defence against infection could therefore be a promising approach. Defensive ability of an animal has two main mechanisms: resistance (ability to control the pathogen burden) and tolerance (ability to maintain performance when pathogen burden increases). When it is difficult to distinguish between resistance and tolerance, defensive ability is measured as resilience that is the ability to maintain performance during a disease outbreak regardless of pathogen burden. Studies have focused on the genetics of resistance and resilience with little known about the genetics of tolerance and its relationship with resistance and resilience. The objectives of this thesis were to: 1) estimate the genetic variation in resistance, tolerance, and resilience to infection in order to assess the amenability of these traits for selective breeding in farm animals, 2) estimate the genetic correlation between resistance, tolerance and resilience and 3) detect genomic regions associated with resistance, tolerance, and resilience.

    In chapter 2, we studied the variation among sows in response to porcine reproductive and respiratory syndrome (PRRS). First a statistical method was developed to detect PRRS outbreaks based on reproduction records of sows. The method showed a high sensitivity (78%) for disease phases. Then the variation of sows in response to PRRS was quantified using 2 models on the traits number of piglets born alive (NBA) and number of piglets born dead (LOSS): 1) bivariate model considering the trait in healthy and disease phases as different traits, and 2) reaction norm model modelling the response of sows as a linear regression of the trait on herd-year-week estimates of NBA. Trait correlations between healthy and disease phases deviated from unity (0.57±0.13 – 0.87±0.18). The repeatabilities ranged from 0.07±0.027 to 0.16±0.005. The reaction norm model had higher predictive ability in disease phase compared to the bivariate model.

    In chapter 3 we studied 1) the genetic variation in resistance and tolerance of sheep to gastrointestinal nematode infection and 2) the genetic correlation between resistance and tolerance. Sire models on faecal nematode egg count (FEC), IgA, and pepsinogen were used to study the genetic variation in resistance. Heritability for resistance traits ranged from 0.19±0.10 to 0.59±0.20. A random regression model was used to study the reaction norm of sheep body weight on FEC as an estimate of tolerance to nematode infection. We observed a significant genetic variance in tolerance (P<0.05). Finally a bivariate model was used to study the genetic correlation between resistance and tolerance. We observed a negative genetic correlation (-0.63±0.25) between resistance and tolerance.

    In chapter 4, we studied the response to selection in resistance and tolerance when using estimated breeding values for resilience. We used Monte Carlo simulation to generate 100 half-sib families with known breeding values for resistance (pathogen burden) and tolerance. We used selection index theory to predict response to selection for resistance and tolerance: 1) when pathogen burden is known and selection is based on true breeding values for resistance and tolerance and 2) when pathogen burden is unknown and selection is based on estimated breeding values for resilience. Using EBV for resilience in absence of records for pathogen burden resulted in favourable responses in resistance and tolerance to infections, with more emphasis on tolerance than on resistance. However, more genetic gain in resistance and tolerance could be achieved when pathogen burden was known.

    In chapter 5 we studied genomics regions associated with resistance, resilience, and tolerance to PRRS. Resistance was modelled as sire effect on area under the PRRS viremia curve up to 14 days post infection (AUC14). Resilience was modelled as sire effects on daily growth of pigs up to 28 days post infection (ADG28). Tolerance was modelled as the sire effect on the regression of ADG28 on AUC14. We identified a major genomics region on chromosome 4 associated with resistance and resilience to PRRS. We also identified genomics regions on chromosome 1 associated with tolerance to PRRS.

    In the general discussion (chapter 6) I discussed: 1) response to infection as a special case of genotype by environment interaction, 2) random regression model as a statistical tool for studying response to disease, 3) advantages and requirements of random regression models, and 4) selective breeding of farm animals for resistance, tolerance, and resilience to infections. I concluded that random regression is a powerful approach to estimate response to infection in animals. If the adequate amount of data is available random regression model could estimate breeding values of animals more accurately compared to other models. I also concluded that before including resistance and tolerance into breeding programs, breeders should make sure about the added values of including these traits on genetic progress. Selective breeding for resilience could be a pragmatic approach to simultaneously improve resistance and tolerance.

    'Nederland is een veterinair voorbeeldland'
    Vermaas, M. ; Hellebrekers, L.J. - \ 2015
    Boerderij 100 (2015)38. - ISSN 0006-5617 - p. 16 - 18.
    dierziekten - diergezondheid - infectieziekten - onderzoek - zoönosen - volksgezondheid - animal diseases - animal health - infectious diseases - research - zoonoses - public health
    Ludo Hellebrekers is sinds 1 juni directeur van het Centraal Veterinair Instituut. Goede samenwerking met alle ketenpartijen en kennisgebieden is volgens hem essentieel.
    Foot-and-mouth disease virus : the role of infection routes and species differences in the transmission of FMDV
    Bravo De Rueda Cabrera, C. - \ 2015
    Wageningen University. Promotor(en): Mart de Jong, co-promotor(en): Aldo Dekker; Phaedra Eble. - Wageningen : Wageningen University - ISBN 9789462573284 - 137
    mond- en klauwzeervirus - mond- en klauwzeer - infectieziekten - ziekteoverdracht - ziektebestrijding - infectiebestrijding - soortverschillen - epidemiologie - diergeneeskunde - foot-and-mouth disease virus - foot and mouth disease - infectious diseases - disease transmission - disease control - infection control - species differences - epidemiology - veterinary science

    ÁFoot-and-mouth disease is a contagious viral disease of cloven-hoofed animals (e.g. cattle, sheep, pigs) and can cause severe economic losses to the farm animal industries. The aim of this thesis was to quantify underlying mechanisms regarding transmission of FMDV. With data from past animal experiments we identified the factors which are associated with the amount of virus shed by infected animals and thus may be of importance for transmission of the virus. In an experimental study, the contribution of the environment on the transmission of FMDV was investigated by using a new mathematical model in which the contribution of the environment on transmission was incorporated. Roughly 44% of the transmission of FMDV occurred through the environment that was contaminated with se-excretions from FMDV infected animals. The role of the different species on the transmission of FMDV was investigated with a transmission study of FMDV between infected sheep and naïve cattle. Sheep were found to be less infectious than cattle but similarly susceptible. Using a so-called next-generation matrix, transmission of FMDV in mixed cattle-sheep populations (with different proportions of cattle and different proportions of vaccinated animals) was quantified and the effects of different vaccination strategies against FMDV were analysed. In mixed populations of cattle and sheep, transmission of FMDV is higher when more cattle are present. In populations with more than 14% cattle, targeting vaccination to cattle only can be sufficient to control FMDV.

    The results of this thesis show that transmission of FMDV can occur via a contaminated environment, (without animal presence) and that sheep seem to play a limited role in the transmission of FMDV. These results can be used to improve the control measures to prevent and control FMDV in different animal populations.

    Dierenlab beschermt mensen
    Sikkema, A. ; Bianchi, A.T.J. - \ 2015
    WageningenWorld (2015)1. - ISSN 2210-7908 - p. 24 - 27.
    dierziekten - infectieziekten - zoönosen - virusziekten - onderzoek - diergezondheid - vaccins - aviaire influenza - q-koorts - animal diseases - infectious diseases - zoonoses - viral diseases - research - animal health - vaccines - avian influenza - q fever
    Nederland krijgt steeds meer te maken met besmettelijke dierziektes die ook mensen ziek kunnen maken, zoals vogelgriep. Om daar goed onderzoek naar te doen is een lab gebouwd waarin levende, besmette landbouwhuisdieren gehouden worden. Geen virus kan eruit ontsnappen. ‘Zelfs het DNA wordt vernietigd.’
    Interview Professor Joost van Neerven over onderzoek naar vermindering van allergieën door gerichte voeding en aanvullende micronutriënten
    Neerven, R.J.J. van - \ 2014
    Wageningen : Wageningen UR
    voeding en gezondheid - voedselonderzoek - immuunsysteem - ziektepreventie - infectieziekten - allergieën - gezondheidsbevordering - nutrition and health - food research - immune system - disease prevention - infectious diseases - allergies - health promotion
    Met gerichte voeding en aanvullende micronutriënten kan de weerstand tegen infecties in de luchtwegen, tegen allergieën, en tegen ontstekingen worden vergroot. Dat is van groot belang voor kinderen onder de 5 jaar en voor 65-plussers, die het vaakst door deze aandoeningen worden geplaagd. De weerstand in weefsels die bedekt zijn met een slijmvlies in het gebied van de mond, keel, en neus is nog nauwelijks onderzocht. Toch kan dit onderzoek veel opleveren, vindt prof. Joost van Neerven.
    Mucosal immunity : barriers, bugs, and balance
    Neerven, R.J.J. van - \ 2014
    Wageningen : Wageningen University, Wageningen UR - ISBN 9789462571952 - 24
    immuniteit - immuniteitsreactie - immuunsysteem - immunologie - infectieziekten - ontsteking - orale vaccinatie - voeding - immunity - immune response - immune system - immunology - infectious diseases - inflammation - oral vaccination - nutrition
    Mechanisms underlying disease transmission between spatially separated animals
    Bunnik, B.A.D. van - \ 2014
    Wageningen University. Promotor(en): Mart de Jong, co-promotor(en): Thomas Hagenaars; Gonnie Nodelijk. - Wageningen : Wageningen University - ISBN 9789461739537 - 150
    dieren - vleeskuikens - infectieziekten - ziekteoverdracht - gastheren (dieren, mensen, planten) - wiskundige modellen - epidemiologie - diergeneeskunde - animals - broilers - infectious diseases - disease transmission - hosts - mathematical models - epidemiology - veterinary science

    Transmission of infections between spatially separated hosts is a common problem, not only during major outbreaks of livestock diseases, but also in many other settings such as the transmission of infectious diseases between plants and crops or in healthcare settings. During the last major epidemics of livestock diseases in the Netherlands and abroad, disease transmission events occurred despite movement bans and other (bio-)security measures, implying that indirect transmission plays a major role. A better understanding of indirect transmission is necessary to put in place evidence based bio-security measures against neighbourhood (indirect) transmission. To gain more insight in the mechanisms underlying indirect transmission a series of experimental studies combined with mathematical modelling were conducted of which the results are presented in this thesis. First the effect of acidification of drinking water on the transmission parameters of direct and indirect transmission of Campylobacter jejuni (C. jejuni) between broilers was studied. It was shown that acidified drinking water has an effect on indirect transmission but not on direct transmission of C. jejuni between broilers. The sender and receiver sub-process of indirect transmission was then studied in more detail and it was shown that a significant negative interaction effect between acidification of the sender and receiver sub-processes exists, indicating that there is no additional effect of acidification of the drinking water on both sides of the transmission process compared to acidified drinking water only on one side. To study the transport of the pathogen in the environment in more detail, a series of indirect transmission experiments was carried out and a model framework was developed to study indirect transmission between spatially separated hosts. These studies showed that indirect transmission of C. jejuni between broilers is best described by a multistage environmental route from sending to receiving animal, suggesting that indirect transmission occurs through progressive (but slow) contamination of the environment surrounding the source. Indirect transmission experiments where repeated with both C. jejuni and Escherichia coli and the results showed that for C. jejuni it takes much longer for the first effective (viable) bacterium to cross the small distance of approximately 75 cm than it does for Escherichia coli. A new modelling approach to study indirect transmission was developed guided by these indirect transmission experiments. This model is capable of accurately describing the pathogen dispersal process by a diffusive transport mechanism which includes pathogen mortality. Lastly, a range of dose-response models were compared and tested how well these fitted to the data from a dose-response experiment. Here it was shown that for interpolation purposes two relatively simple models are best capable of describing the data from the dose-response experiment. For extrapolation purposes, however, it was shown that from the models that were studied a model that abides by the independent action hypothesis is best.

    Lokschapen vangen teken in het bos
    Sikkema, A. ; Wieren, S.E. van - \ 2014
    Wageningen UR/Stichting voor Duurzame Ontwikkeling
    schapen - gastheer parasiet relaties - vangmethoden - lokken - natuurgebieden - borrelia burgdorferi - humane ziekten - lyme-ziekte - infectieziekten - insecticiden - experimenten - wetenschappelijk onderzoek - bosecologie - sheep - host parasite relationships - trapping - baiting - natural areas - borrelia burgdorferi - human diseases - lyme disease - infectious diseases - insecticides - experiments - scientific research - forest ecology
    De Wageningse onderzoeker Sip van Wieren wil lokschapen inzetten om teken weg te vangen in natuurgebieden. Op die manier kunnen schaapskuddes er voor zorgen dat mensen prettig kunnen recreëren in het bos.
    Population genetics and disease ecology of European wild boar
    Goedbloed, D.J. - \ 2013
    Wageningen University. Promotor(en): Herbert Prins; Ron Ydenberg, co-promotor(en): Pim van Hooft. - S.l. : s.n. - ISBN 9789461737236 - 123
    wilde varkens - sus scrofa - infectieziekten - populatiegenetica - ecologie - mycoplasma hyopneumoniae - varkenscircovirus-1 - ziekteoverdracht - fauna - noordwest-europa - wild pigs - sus scrofa - infectious diseases - population genetics - ecology - mycoplasma hyopneumoniae - porcine circovirus-1 - disease transmission - fauna - northwestern europe
    Welke factoren beïnvloeden de frequentie van de ziekten in wilde populaties? Het promotieonderzoek van Daniel Goedbloed beoordeelde de invloed van demografische, genetische en omgevingsfactoren op de frequentie van twee infectieziekten in Noordwest-Europese wilde zwijnen populaties.
    Onderzoek naar de oorzaak van 'zwarte vaten in radijs'
    Ludeking, D.J.W. ; Hamelink, R. ; Hofland-Zijlstra, J.D. ; Wensveen, W. van - \ 2013
    Bleiswijk : Wageningen UR Glastuinbouw (Rapporten WUR GTB 1241) - 38
    radijsjes - raphanus sativus - symptomen - infectieziekten - verkleuring - vaatbundels - stenotrophomonas - glastuinbouw - glasgroenten - nederland - radishes - raphanus sativus - symptoms - infectious diseases - discoloration - vascular bundles - stenotrophomonas - greenhouse horticulture - greenhouse vegetables - netherlands
    Op één Nederlands radijsbedrijf treedt vanaf de herfst van 2007 een verschijnsel op, waarbij radijsknollen bruine tot zwarte vaatbundels vertonen. De radijsplantjes blijven veelal achter in groei of gaan dood. Uitwendig is de verkleuring niet altijd waarneembaar, waardoor deze knollen toch in het handelskanaal terecht kunnen komen. Sinds het voorjaar van 2008 is het verschijnsel ook op een ander bedrijf opgetreden. Op de betreffende bedrijven breidt het verschijnsel zich elk jaar uit en leidt tot veel schade in het winterhalfjaar. Een bekende ziekteverwekker is in voorgaande onderzoeken niet geïsoleerd, daarom is er in dit onderzoek verder gezocht om een onbekende ziekteverwekker te kunnen identificeren. Gedurende dit onderzoek is er vastgesteld dat de ziekte overdraagbaar is via grond en wordt veroorzaakt door de bacterie Stenotrophomonas spp. De bacterie is geïsoleerd uit geïnfecteerde knollen, er is een moleculaire analyse gemaakt van de isolaten en de postulaten van Koch zijn toegepast. Op basis van de analyse en het terug toetsen van het pathogeen kan worden geconcludeerd dat Stenotrophomonas spp. verantwoordelijk is voor de symptomen in het gewas.
    Economic evaluation of FMD management options: implications for science and policy
    Bergevoet, Ron - \ 2012
    livestock farming - foot and mouth disease - infectious diseases - disease control - vaccination - economic impact - market economics - exports - losses - european union
    Het Centraal Veterinair Instituut versterkt het onderzoek naar opkomende zoönosen
    Poel, W.H.M. van der - \ 2012
    Tijdschrift voor Diergeneeskunde 137 (2012)12. - ISSN 0040-7453 - p. 796 - 802.
    zoönosen - dierziektepreventie - ziektebestrijding - infectieziekten - volksgezondheid - onderzoek - zoonoses - animal disease prevention - disease control - infectious diseases - public health - research - toxoplasma-gondii infection - avian influenza-virus - valley fever virus - west-nile-virus - streptococcus-suis - epidemiology - pathogenesis - netherlands - responses
    Een zoönose is een infectieziekte die overgedragen kan worden van gewervelde dieren naar mensen of omgekeerd. Ruim 60 procent van de ziekteverwekkers bij mensen heeft een zoönotisch karakter. Het verkleinen van het risico van zoönosen voor de mens is één van de taken van het CVI. Samen met diverse partners richt het CVI zich op het vroegtijdig opsporen van deze ziekteverwekkers in het dierlijk reservoir en op het ontwikkelen van bestrijdingsmethoden. Het CVI is referentiecentrum voor aangifteplichtige dierziekten inclusief zoönosen en voert onderzoeksprojecten uit op het gebied van dierziektebestrijding voor zowel de overheid als in opdracht van externe partijen en in (inter)nationale samenwerkingsverbanden. Onderzoek aan zoönosen is daar een belangrijk onderdeel van. Ten behoeve van een betere preventie, opsporing en bestrijding van zoönosen wil het CVI het onderzoek naar opkomende zoönosen versterken. Een aantal voorbeelden van zoönosen waar het CVI aan werkt, wordt kort besproken.
    Zoönosen : uit de ziekenboeg
    Haenen, O.L.M. ; Beurden, S.J. van; Engelsma, M.Y. - \ 2012
    Aquacultuur 27 (2012)1. - ISSN 1382-2764 - p. 24 - 28.
    zoönosen - volksgezondheid - aquacultuur - kweekvis - infectieziekten - bedrijfshygiëne - zoonoses - public health - aquaculture - farmed fish - infectious diseases - industrial hygiene
    Zoönosen zijn infectieziekten die overdraagbaar van dier op mens, zowel vanuit koudbloedige als warmbloedige dieren Ook bij contacten met aquacultuur- en visserijdieren is er een klein risico voor de mens op het oplopen van een ziekte. In de Nederlandse aquacultuur komen af en toe zoönotische bacteriën voor, die contactzoönose kunnen veroorzaken. Met voldoende hygiëne op aquacultuurbedrijven ontwikkelen deze bacteriën zich meestal niet tot een zoönose. Toch is het belangrijk, dat men op de hoogte is van risico's en mee helpt aan een goede diagnose van een aquatische zoönose, omdat deze in eerste instantie door de huisarts vaak niet als zodanig herkend wordt.
    The relation between farming practices, ecosystem, and white spot in syndrome virus (WSSV) disease outbreaks in penaeus monodon farms in the Philippines
    Tendencia Alapide, E. - \ 2012
    Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Roel Bosma; J.H. Primavera. - S.l. : s.n. - ISBN 9789461733702 - 135
    garnalen - witte-vlekken-syndroom-virus - garnalenteelt - uitbraken (ziekten) - epidemiologie - infectieziekten - dierziektepreventie - aquatische ecosystemen - fysicochemische eigenschappen - mangroves - filippijnen - shrimps - white spot syndrome virus - shrimp culture - outbreaks - epidemiology - infectious diseases - animal disease prevention - aquatic ecosystems - physicochemical properties - mangroves - philippines

    The white spot syndrome virus (WSSV) affecting shrimp aquaculture in most producing countries has caused huge economic losses resulting in bankruptcy to both large and small farmers. Studies done on WSSV epidemiology were mostly tank-based and on species other than Penaeus monodon. There is a need to investigate WSSV epidemiology in P. monodon in on-farm situations, thus including both risk and protective factors. This thesis aimed to generate knowledge that can improve prevention against WSSV in shrimp culture through better farm husbandry by studying the epidemiology of WSSV in on-farm situations. To achieve this goal data from cross-sectional and case studies were analysed to identify on-farm WSSV risk and protective factors, and longitudinal studies were done to assess factors affecting water quality and causing WSSV infection to result in an outbreak.

    The thesis identified the following WSSV risk factors related to the physico-chemical parameters of the water: low and fluctuating temperature, low and fluctuating salinity, and pH fluctuation. The risk of high temperature and high salinity for an outbreak of WSV disease may be related to fluctuations in these two parameters. Risk factors related to farm husbandry techniques were feeding with molluscs, sludge removal and its deposition on the dike, sharing water source with other farms and having the same receiving and intake water. Identified WSSV protective factors were high mangrove to pond area ratio, feeding with natural food or phytoplankton, and higher percentage of beneficial bacteria like the yellow colonies that grow on thiosulphate citrate bilesalt sucrose agar, a Vibrio selective medium.

    Results of the longitudinal studies demonstrated that WSSV infection may not result in outbreaks in greenwater pond and in ponds with mangroves in the receiving environment. Our results did not provide explanations why the WSSV infection did not result in an outbreak in farms with mangroves in the receiving environment. In greenwater ponds, this was attributed to the better water and soil quality, higher plankton count, and higher heterotrophic bacterial count.

    Infectierisico’s van de veehouderij voor omwonenden
    Maassen, C.B.M. ; Duijkeren, E. van; Duynhoven, Y.T.H.P. van; Dusseldorp, A. ; Geenen, P. ; Koeijer, A.A. de; Koopmans, M.P.G. ; Loos, F. ; Jacobs-Reitsma, W.F. ; Jonge, M. de; Giessen, A.W. van de - \ 2012
    Bilthoven : RIVM - 65
    veehouderij - zoönosen - q-koorts - volksgezondheid - infectieziekten - livestock farming - zoonoses - q fever - public health - infectious diseases
    Momenteel kunnen er geen wetenschappelijk onderbouwde uitspraken worden gedaan over het infectierisico van omwonenden van veehouderijen, met uitzondering van Q-koorts. Het is aangetoond dat omwonenden van melkgeitenbedrijven met Q-koorts, een verhoogd risico hebben om deze infectieziekte te krijgen. Voor de overige zoönosen (infectieziekten die van dier op mens worden overgedragen) zijn onvoldoende gegevens beschikbaar over het risico in relatie tot de afstand tot veehouderijen, het bedrijfstype en de bedrijfsgrootte. Wel is bekend dat veehouders, medewerkers op veehouderijen en dierenartsen een verhoogd risico hebben om bepaalde zoönosen op te lopen. Direct contact met dieren is daarbij vaak een risicofactor.
    Vaccins beschermen dier én mens
    Rijsman, V.M.C. - \ 2012
    Kennis Online 9 (2012)april. - p. 19 - 19.
    infectieziekten - zoönosen - diergezondheid - volksgezondheid - dierziektepreventie - vaccins - infectious diseases - zoonoses - animal health - public health - animal disease prevention - vaccines
    Het bedrijf MSD Animal Health werkt met onderzoekers van Wageningen UR, het RIVM en de Universiteit Utrecht aan een betere bestrijding van infectieziekten die van dier op mens kunnen overslaan. 'We kunnen nu enkele producten ontwikkelen die mogelijk nooit commercieel aantrekkelijk zullen zijn, maar maatschappelijk wel relevant zijn.'
    Risk assessment framework for emerging vector-borne livestock diseases
    Vos, C.J. de; Hoek, M.R. ; Fischer, E.A.J. ; Koeijer, A.A. de; Bremmer, J. - \ 2012
    Lelystad : Wageningen UR, Central Veterinary Institute - 76
    veehouderij - dierziekten - infectieziekten - risicoschatting - risicoanalyse - besluitvorming - vectoren, ziekten - livestock farming - animal diseases - infectious diseases - risk assessment - risk analysis - decision making - disease vectors
    The objective of this project was to develop a framework for risk assessment of introduction, establishment, spread and persistence of vector-borne livestock diseases by integrating the essential elements of different approaches. This framework will help risk analysts to assess the risk of vector-borne diseases, considering both likelihood of occurrence and potential impact to inform stakeholders on behalf of their decision making.
    De ene MRSA is de andere niet
    Wagenaar, Jaap - \ 2012
    livestock farming - staphylococcus aureus - disease distribution - infectious diseases - veterinary science - public health - disease resistance
    Agenda infectieuze ziekten paard
    Anonymous, - \ 2011
    Sectorraad Paarden - 29 p.
    paarden - paardenziekten - infectieziekten - dierenwelzijn - diergezondheid - dierziektepreventie - paardenfokkerij - horses - horse diseases - infectious diseases - animal welfare - animal health - animal disease prevention - horse breeding
    De agenda infectieuze paardenziekten is mede op verzoek van het ministerie van EL&I geschreven door de Sectorraad Paarden (SRP) voor beleidsmakers van paardensport- en fokkerijorganisaties, hippische ondernemers en de overheid. In deze agenda geeft de SRP haar visie hoe te komen tot de borging van een goede gezondheid bij paarden.
    Knoflook remt App
    Mul, M.F. ; Becker, P.M. ; Peet-Schwering, C.M.C. van der; Wikselaar, P.G. van; Wisselink, H.J. ; Stockhofe, N. - \ 2011
    V-focus 8 (2011)4. - ISSN 1574-1575 - p. 34 - 35.
    varkenshouderij - bacteriële longontsteking - actinobacillus pleuropneumoniae - varkensziekten - infectieziekten - knoflook - allium sativum - alternatieve geneeskunde - pig farming - bacterial pneumonia - actinobacillus pleuropneumoniae - swine diseases - infectious diseases - garlic - allium sativum - alternative medicine
    De Animal Sciences Group van Wageningen UR heeft in opdracht van biologische varkenshouders onderzocht of het mogelijk is om in plaats van antibiotica, knoflook te gebruiken voor de bestrijding van longontsteking door de bacterie Actinobacillus pleuropneumoniae (App). Uit de resultaten blijkt dat Allyl Methyl Sulfi de (AMS), een omzettingsproduct van knoflook, de groei van App remt.
    Scrapie
    Anonymous, - \ 2010
    Lelystad : Central Veterinary Institute, Wageningen UR
    geiten - scrapie - schapen - infectieziekten - goats - scrapie - sheep - infectious diseases
    Deze website geeft informatie over scrapie. Deze ziekte komt voor bij geiten en schapen
    Q-fever in wild animals in Europe, a concern for hunters
    Rotterdam, B. van; Langelaar, M. ; Giessen, J. van der; Roest, H.I.J. ; Grone, A. - \ 2010
    Tijdschrift voor Diergeneeskunde 135 (2010)10. - ISSN 0040-7453 - p. 420 - 422.
    wilde dieren - q-koorts - coxiella burnetii - infectieziekten - ziektedistributie - tekenbeten - europa - literatuuroverzichten - wild animals - q fever - coxiella burnetii - infectious diseases - disease distribution - tick bites - europe - literature reviews - borne zoonotic bacteria - ixodes-ricinus ticks - coxiella-burnetii - serologic survey - northern spain - prevalence - pathogens - infection
    Het is onbekend of, hoe en in welke mate Coxiella burnetii circuleert onder wild in Nederland. In dit artikel wordt ingegaan op de literatuur over de circulatie van Coxiella burnetii onder niet gedomesticeerde diersoorten in Europa.
    Socio-psychological research on barriers and incentives to a clinically suspicious situation at a farm in order to report early detection of notifiable animal diseases
    Elbers, A.R.W. - \ 2010
    Tijdschrift voor Diergeneeskunde 135 (2010)14-15. - ISSN 0040-7453 - p. 566 - 569.
    veehouderij - rundveeziekten - varkensziekten - pluimveeziekten - infectieziekten - virusziekten - detectie - risicoschatting - alarmsystemen - veterinaire praktijk - livestock farming - cattle diseases - swine diseases - poultry diseases - infectious diseases - viral diseases - detection - risk assessment - alarms - veterinary practice
    Enige tijd geleden heeft de KNMVD actief medewerking verleend aan onderzoek naar belemmeringen en stimuli om een klinisch verdachte situatie op veehouderijen te melden bij het centrale meldpunt van de VWA. Recent zijn resultaten van dit onderzoek gepubliceerd in het wetenschappelijke tijdschrift Veterinary Microbiology en geaccepteerd in Rev. sci. tech. OIE. Omdat deze problematiek relevant is voor veel dierenartsen, is hierbij van de artikelen een uitgebreide samenvatting gemaakt.
    Verbetering van strovertering
    Spits, H.G. - \ 2010
    Kennisakker.nl 2010 (2010)20 jan..
    tarwe - infectieziekten - fusarium - septoria - stro - plantenresten - plantenziektebestrijding - gewasbescherming - akkerbouw - wheat - infectious diseases - fusarium - septoria - straw - plant residues - plant disease control - plant protection - arable farming
    Stoppelresten en stro van tarwe kunnen een bron voor infectie door Septoria, DTR en (aar)fusarium zijn. In het kader van de beheersing van deze ziekten kan het belangrijk zijn om de gewasresten zo te bewerken dat ze als ziektebron geminimaliseerd worden. Doel van dit onderzoek is om een effectief en efficiënt systeem voor de behandeling van gewasresten te ontwikkelen, zodanig dat de gewasresten (ook als er niet geploegd wordt) voldoende snel verteren, waardoor de ziektedruk kan worden verlaagd. Na twee jaar onderzoek zijn er nog geen harde conclusies te trekken over de invloed van behandeling van gewasresten op de onderdrukking van de ziektedruk. De indruk ontstaat dat verschillen erg klein zijn en dat de tarweteelt geen meetbare negatieve invloeden ondervindt van gewasresten van de voorgaande tarweteelt.
    Risico's voor de volksgezondheid : hoe gaan we ermee om?
    Kimman, T.G. ; Bianchi, A.T.J. - \ 2010
    In: Over zorgvuldige veehouderij. Veel instrumenten, één concert / Eijsackers, H., Scholten, M., Wageningen : Wageningen UR (Essaybundel 2010 ) - ISBN 9789085858959 - p. 76 - 85.
    veehouderij - dierziekten - diergezondheid - zoönosen - risico - volksgezondheid - infectieziekten - livestock farming - animal diseases - animal health - zoonoses - risk - public health - infectious diseases
    In dit essay identificeren de auteurs een aantal factoren die nodig kunnen zijn om het vertrouwen van burgers in de veiligheid van de veehouderij en de bescherming van hun gezondheid te borgen. Een volstrekt open communicatie is nodig om een gesprekmogelijk te maken over volksgezondheidsbedreigingen en de proportionaliteit van maatregelen om die te beschermen. Naast een adequate en proactieve aanpak van bedreigingen, is dat nodig om de Licence-to-Produce van de veehouderij zeker te stellen.
    Zoonose Vibrio vulnificus: meldingsplicht raadzaam
    Dijkstra, A. ; Haenen, O.L.M. ; Moller, L. - \ 2010
    Nederlands Tijdschrift voor Geneeskunde 2010 (2010)154. - ISSN 0028-2162 - p. A2320 - A2320.
    vibrio vulnificus - viskwekerijen - zoönosen - gezondheid - infectieziekten - vibrio vulnificus - fish farms - zoonoses - health - infectious diseases
    Op de lijst van meldingsplichtige infectieziekten komen een aantal zoönosen voor, zoals pest, rabiës en leptospirose. De relatief onbekende zoönotische Vibrio vulnificus valt opmerkelijk genoeg niet onder de meldingsplichtige infectieziekten. Juist vanwege het zeer agressieve beloop van een invasieve V. vulnificus-infectie is een snelle diagnose van belang om adequaat medisch te kunnen handelen. Tevens lijkt V. vulnificus wereldwijd steeds vaker de kop op te steken, zelfs in landen waar men deze bacterie niet zou verwachten, zoals Spanje, Denemarken, Japan en ook Nederland.
    Aandacht voor ziekten op bedrijf
    Bergevoet, R.H.M. - \ 2010
    Kennis Online 7 (2010)nov. - p. 9 - 9.
    dierziekten - infectieziekten - overheidsbeleid - dierziektepreventie - animal diseases - infectious diseases - government policy - animal disease prevention
    Bedrijfsgebonden ziekten treffen niet louter de sector, maar spelen ook een rol bij antibioticaresistentie, dierenwelzijn en volksgezondheid door zoönosen. Om tot een aanpak te komen stelde Wageningen UR Livestock Research met hulp van stakeholders een lijst op van ziekten die aandacht behoeven.
    Het "PEPEIRA" project beoordeelt het risico van pepinomozaïekvirus
    Hamelink, R. ; Stijger, I. ; Vlugt, R.A.A. van der; Schenk, M.F. - \ 2010
    pepinomozaïekvirus - gevaren - infectieziekten - tomaten - europese unie - pepino mosaic virus - hazards - infectious diseases - tomatoes - european union
    De landen binnen de Europese Unie verschillen soms sterk van mening over het gevaar van pepinomozaïekvirus (PepMV). Ondanks het feit dat dit virus al 1999 is opgedoken is nog geen definitieve fytosanitaire status toegekend. Bovendien is in 2005 een nieuwe stam van het virus opgedoken (de Chili,2 stam) die sindsdien naast de al aanwezige stam (de EU,stam) voorkomt. Om een wetenschappelijke onderbouwing te geven van de fytosanitaire status van PepMV is het EPEIRA,project gestart.Aan de hand van de resultaten van de kasproeven en o.a. informatie over de zaadoverdraagbaarheid, het voorkomen van de PepMV,stammen en de beschikbaarheid van goede maatregelen die het virus kunnen inperken, zal nu de discussie over de fytosanitaire status plaatsvinden.
    Risicobeoordeling schapenscheren en schapenwol voor mens en dier in de Nederlandse wolproductieketen
    Elbers, A.R.W. ; Roest, H.I.J. ; Zijderveld, F.G. van - \ 2009
    Lelystad : Wageningen UR, Centraal Veterinair Instituut - 23
    schapenhouderij - wolproductie - wol - scheren - infectieziekten - risicoschatting - ziektedistributie - mens-dier relaties - maatregelen - sheep farming - wool production - wool - shearing - infectious diseases - risk assessment - disease distribution - human-animal relationships - measures
    Het doel van dit onderzoek is een risicobeoordeling van de microbiologische risico's voor mens en dier van het schapenscheren, transport en het bewerken van schapenwol in de wolproductieketen in Nederland, inclusief de opties voor eventueel noodzakelijke risicoreducerende maatregelen. De VWA wilde de volgende vragen beantwoord hebben: 1. Welke microbiologische gevaren vormen in Nederland een risico voor infectie van en verspreiding onder mensen en dieren naar aanleiding van directe en indirecte contacten met het product wol in de wolproductieketen? 2. Kunt u deze microbiologische risico's in prioritaire volgorde plaatsen (kwalitatieve of indien mogelijk semikwantitatieve risicobeoordeling)? 3. Als er risico's aanwezig zijn, die op basis van een expertmening niet verwaarloosbaar klein zijn, welke risicoreducerende maatregelen kunnen mogelijk worden toegepast in de productieketen en op welk moment?
    Beweegredenen van commerciële veehouders en hobbydierhouders om te vaccineren tegen Blauwtong tijdens een vrijwillige vaccinatiecampagne in 2008 en 2009 in Nederland
    Elbers, A.R.W. ; Koeijer, A.A. de; Rijn, P.A. van - \ 2009
    Lelystad : Wageningen UR, Centraal Veterinair Instituut (Rapport 09/CVI0311) - 27
    diergezondheid - bluetonguevirus - vaccinatie - diergeneeskunde - infectieziekten - animal health - bluetongue virus - vaccination - veterinary science - infectious diseases
    Onderzoek naar beweegredenen van veehouders om hun vee in te laten enten tegen het blauwtongvirus
    Project 8: prevalentieschatting en risicofactorenanalyse MRSA bij varkens
    Broens, E.M. ; Graat, E.A.M. ; Jong, M.C.M. de; Meijerink, M. ; Broek, I.V.F. van den; Cleef, B.A.G.L. van; Huijsdens, X.W. ; Mevius, D.J. ; Oosterom, R.A.A. van; Wolf, P. de - \ 2009
    In: Veegerelateerde MRSA: epidemiologie in dierlijke productieketens, transmissie naar de mens en karakterisatie van de kloon / Wagenaar, J.A., van de Giessen, A.W., Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM) (RIVM-rapport 330224001) - p. 49 - 68.
    varkenshouderij - varkens - infectieziekten - staphylococcus aureus - volksgezondheid - ziekteprevalentie - ziektedistributie - zoönosen - pig farming - pigs - infectious diseases - staphylococcus aureus - public health - disease prevalence - disease distribution - zoonoses
    Rapport over het voorkomen van MRSA op varkenshouderijen. Geconcludeerd wordt dat MRSA op veel zeugenbedrijven voorkomt en dat de prevalentie stijgt. Grote bedrijven hebben hebben een verhoogd risico. Het risico wordt daarnaast ook nog bepaald door een aantal factoren. Voor wat betreft de besmetting van MRSA door mensen wordt geconcludeerd dat mensen die intensief contact met MRSA-positieve varkens hebben een sterk verhoogd risico hebben om zelf MRSA-positief te zijn.
    De invloed van houderijaspecten op het risico van ziekte-uitbraak op varkensbedrijven en de sterke en zwakke punten in gangbare en high health systemen
    Bokma-Bakker, M.H. ; Bergevoet, R.H.M. ; Napel, J. ten; Swanenburg, M. - \ 2009
    Lelystad : Animal Sciences Group (Rapport / Wageningen UR Livestock Research 242) - 33
    varkens - varkenshouderij - dierhouderij - infectieziekten - uitbraken (ziekten) - ziekteresistentie - diergezondheid - bedrijfssystemen - intensieve veehouderij - biologische landbouw - nederland - dierziektepreventie - pigs - pig farming - animal husbandry - infectious diseases - outbreaks - disease resistance - animal health - farming systems - intensive livestock farming - organic farming - netherlands - animal disease prevention
    Stand van zaken: Klimaatverandering en gezondheid in Nederland
    Vliet, A.J.H. van; Huynen, M. - \ 2009
    Nederlands Tijdschrift voor Geneeskunde 153 (2009). - ISSN 0028-2162 - p. A1515 - A1515.
    klimaatverandering - gezondheid - risicofactoren - allergieën - vectoren, ziekten - infectieziekten - climatic change - health - risk factors - allergies - disease vectors - infectious diseases
    Klimaatverandering heeft mogelijke gezondheidseffecten in Nederland, zoals veranderingen in (a) temperatuurgerelateerde effecten, hittestress en luchtverontreiniging, (b) allergieën, (c) vectorgebonden infectieziekten en (d) voedsel- en watergebonden infectieziekten. Over de precieze mate waarin en de snelheid waarmee gezondheidseffecten zich voordoen verschillen de meningen en is nog onvoldoende duidelijkheid. Dit geldt tevens voor de mate waarin de samenleving zich op de mogelijke gezondheidseffecten moet of kan aanpassen. De hiaten in onze kennis zijn dus aanzienlijk. Wetenschappers en deskundigen maken zich duidelijk zorgen over de geringe aandacht voor de gezondheidsgevolgen van klimaatverandering in Nederland. In 2009 is dan ook een voorstel tot een onderzoeksprogramma ‘Klimaatverandering en Gezondheid’ opgesteld
    Veegerelateerde MRSA: epidemiologie in dierlijke productieketens, transmissie naar de mens en karakterisatie van de kloon
    Wagenaar, J.A. ; Giessen, A.W. van de - \ 2009
    Bilthoven : RIVM (RIVM rapport 330224001) - 170
    intensieve veehouderij - veehouderij - staphylococcus aureus - infectieziekten - volksgezondheid - intensive livestock farming - livestock farming - staphylococcus aureus - infectious diseases - public health
    Onderzoek waarin gepoogd werd om meer inzicht te krijgen in het voorkomen van MRSA in de Nederlandse veehouderij. De varkenshouderij, vleeskalverhouderij en pluimveehouderij werden onderzocht. Geconcludeerd wordt dat MRSA wijdverspreid voorkomt in de intensieve veehouderij en dat Nederland hierin niet uniek is. In het bijzonder het type ST398 vormt een probleem, omdat het zich goed kan verspreiden en aanpassen
    Belangrijke rol bloeminfecties bij infecties van kool (Brassica) zaad met Xanthomonas
    Wolf, J.M. van der; Zouwen, P.S. van der; Haas, B.H. de; Köhl, J. - \ 2009
    brassica - zaadproductie - xanthomonas campestris pv. campestris - vermeerderingsmateriaal - infectieziekten - plantenziekten - biologische zaden - biologische plantenveredeling - brassica - seed production - xanthomonas campestris pv. campestris - propagation materials - infectious diseases - plant diseases - organic seeds - organic plant breeding
    Poster met resultaten uit onderzoek naar de fase van de plantontwikkeling tijdens welke infecties met Xanthomonas kunnen leiden tot zaadinfecties, en de rol van de (bestuivende) insecten bij het ontstaan van zaadinfecties
    Het toenemend belang van infectieziekten die worden overgebracht door vectoren
    Scholte, E.J. ; Reusken, C.B.E.M. ; Takken, W. ; Jongejan, F. ; Giessen, J.W.B. van der - \ 2009
    Infectieziekten bulletin 19 (2009)9. - ISSN 0925-711X - p. 311 - 316.
    ziekten overgebracht door vectoren - infectieziekten - geleedpotigen - ziekten overgebracht door teken - ingevoerde infecties - klimaatverandering - zoönosen - ziekten overgebracht door muskieten - volksgezondheid - vector-borne diseases - infectious diseases - arthropods - tickborne diseases - imported infections - climatic change - zoonoses - mosquito-borne diseases - public health
    Dit artikel gaat over de voor Nederland belangrijkste arthropodenvectoren (geleedpotigen, in dit artikel voornamelijk muggen en teken) en de door hen overgebrachte infectieziekten. Daarnaast wordt de rol van landschappelijke aanpassingen, klimaatverandering, intensiever internationaal reizigers- en handelsverkeer en veranderend gedrag met betrekking tot recreatie beschreven. Tenslotte wordt de verdere kennisbehoefte aangegeven
    Q-koorts in Nederland: 2008 en verwachting voor 2009
    Steenbergen, J.E. van; Roest, H.I.J. ; Wijkmans, C.J. ; Duijnhoven, Y. van; Vellema, P. ; Stenvers, O. ; Oomen, T. - \ 2009
    Infectieziekten bulletin 20 (2009)4. - ISSN 0925-711X - p. 132 - 137.
    q-koorts - zoönosen - infectieziekten - coxiella burnetii - ziektedistributie - volksgezondheid - epidemiologische onderzoeken - q fever - zoonoses - infectious diseases - coxiella burnetii - disease distribution - public health - epidemiological surveys
    In 2007 en 2008 deed zich in Nederland een epidemie van Q-koorts voor met resp. 196 en 906 bevestigde ziektegevallen. In dit artikel beschrijven de auteurs het verloop van de epidemie, het onderzoek, de maatregelen en de verwachting van het beloop in 2009. Q-koorts is, met name in het zuidoosten van Nederland, een nieuwe aandoening met belangrijke consequenties voor diagnostiek en therapie
    Vaccinatie moet Q-koorts stoppen
    Roest, H.I.J. - \ 2009
    Kennis Online 6 (2009)juni. - p. 3 - 3.
    veehouderij - q-koorts - coxiella burnetii - infectieziekten - humane ziekten - vaccinatie - geitenziekten - geiten - livestock farming - q fever - coxiella burnetii - infectious diseases - human diseases - vaccination - goat diseases - goats
    Hendrik-Jan Roest van het Centraal Veterinair Instituut (CVI) houdt de Q-koorts voor de ministeries van LNV en VWS in de gaten en geeft de stand van zaken weer
    Panamakanaal wereldprimeur in muggenbestrijding
    Takken, W. - \ 2008
    In: Natuur als Bondgenoot / Osse, J.W.M, Schoonhoven, L.M., Dicke, M., Buiter, R., Leiden : Stichting BWM (Cahiers bio-wetenschappen en maatschappij 4) - ISBN 9789073196490 - p. 76 - 77.
    malaria - culicidae - ziektebestrijding - infectieziekten - panamakanaalzone - gele koorts - ziekten overgebracht door muskieten - malaria - culicidae - disease control - infectious diseases - panama canal zone - yellow fever - mosquito-borne diseases
    Beschrijvende epidemiologie van de Bluetongue virus serotype 8 uitbraken in Nederland in 2006
    Elbers, A.R.W. ; Backx, A. ; Spek, A.N. van der; Ekker, M. ; Leijs, P. ; Steijn, K. ; Langen, H. ; Rijn, P.A. van - \ 2008
    Tijdschrift voor Diergeneeskunde 133 (2008)6. - ISSN 0040-7453 - p. 222 - 229.
    bluetonguevirus - ziekten overgebracht door vectoren - infectieziekten - schapenziekten - bluetongue virus - vector-borne diseases - infectious diseases - sheep diseases
    Epidemiology of Bluetongue virus serotype 8 outbreaks in the Netherlands in 2006. In August 2006 a major epidemic of Bluetongue (bt) occurred in north-western Europe, affecting the Netherlands, Belgium, Germany, Luxemburg, and the north of France. It was caused by bt virus serotype 8 (btv-8), a serotype previously unknown to the eu. Although clinical disease is usually restricted to sheep, this virus also caused clinical disease in a small proportion of cattle. The last clinical outbreak of bt in the Netherlands occurred mid-December 2006. The delay between observation of the first clinical signs by the owner and reporting of a clinically suspect bt situation to the veterinary authorities was approximately 2 weeks. btv-8-associated clinical signs were more prominent in sheep than in cattle, and the relative frequency of specifi c clinical signs was different in cattle and sheep. Morbidity and mortality rates were signifi cantly higher among sheep than among cattle, and a higher proportion of cattle than sheep recovered from clinical disease
    Insects and disease in the 21st century : a wind of change
    Takken, W. - \ 2008
    Wageningen : Wageningen UR - ISBN 9789085852278 - 31
    insecten - ziekten - infectieziekten - humane ziekten - dierziekten - vectoren, ziekten - ziekten overgebracht door vectoren - openbare redes - insects - diseases - infectious diseases - human diseases - animal diseases - disease vectors - vector-borne diseases - public speeches
    In recent years, several other vectors have become world news: the sheep tick was discovered to be the vector of Lyme disease in 1980; the mosquito Culex pipiens began transmitting West Nile virus in North America in 1999; in August 2006, bluetongue virus was discovered in Belgium and the Netherlands, transmitted by biting midges and in 2007, Asian tiger mosquitoes began transmitting Chikungunya virus in northern Italy. Other anecdotes that are worthwhile mentioning, but not very good news because of their potential impact on our society: recorded cases of canine babesiosis in the Netherlands (Nijhof et al. 2007); the establishment of the tick Dermacentor reticulatus in the Netherlands (de Lange et al. 2005, Nijhof et al. 2007); records of the Asian tiger mosquito in southern Germany and Switzerland; the establishment of Aedes japonicus in Belgium and France; annual epidemics of dengue fever in the Caribbean and South America; head lice have become highly resistant to insecticides; and London hotels are frequently infested with bedbugs (Ter Poorten and Prose 2005)
    Introduction and transmission of Encephalomycarditis virus (EMVC) in pig farms : studies to support prevention and control
    Maurice, H. - \ 2008
    Wageningen University. Promotor(en): Ruud Huirne; J.A. Stegeman, co-promotor(en): M. Nielen; F. Koenen. - [S.l.] : S.n. - ISBN 9789085048541 - 140
    encefalomyocarditisvirus - varkens - varkenshouderij - infectieziekten - ziekteoverdracht - ziektepreventie - ziektebestrijding - epidemiologie - dierziektepreventie - encephalomyocarditis virus - pigs - pig farming - infectious diseases - disease transmission - disease prevention - disease control - epidemiology - animal disease prevention
    Clinical manifestations of infections by encephalomyocarditis virus (EMCV), belonging to the genus cardiovirus of the family Picomaviridae, emerged in European pig farms in the nineties. Two types of clinical disease were noticed, acute myocarditis, usually in young piglets, and reproductive failure in sows. To understand its relevance in pigs and develop hypotheses on the origin, cause and nature of infection, the occurrence of EMCV infections was studied in domestic pigs in several European countries. In addition, virus spread in pigs and rats as well as risk factors for clinical appearance of EMCV in domestic pig farms were studied to increase our knowledge of the disease and support its prevention and control. Although outbreaks appeared to be clustered in endemic areas, infection usually was restricted to individual farms. The seroprevalence varied considerably among farms, age categories and countries, while sub-clinical infection with EMCV was quite common. The variable clinical picture in pigs in literature was ascribed to the pathogenicity of the EMCV strains, the available infectious dose and/or the susceptibility of the pigs (age, breed). Local rodent populations were often suggested responsible for the observed clustering and re-occurrence in farms. A matched case-control study on risk factors inducing clinical EMCV revealed the presence of mice (OR = 8.3) as a risk factor. The transmission of a myocardial EMC V-strain in fattening piglets was quantified by the basic reproduction ratio (R0) both from experiments (Ro=1.24, 95%-CI = 0.39 - 4.35) and field data (Ro=1.36, 95%-CI 0.93-2.23). Although these results suggested that EMCV transmission among pigs in most cases will be limited (Ro close to 1), both studies remained inconclusive with respect to the threshold value of R0=l. Therefore it could not be concluded whether EMCV could persist in a pig population by pig-to-pig transmission alone (i.e. Ro>l). To estimate the transmission in a compartmentalised house setting without possible interference of multiple transmission routes (field), a stochastic simulation model was developed to extrapolate the experimental results to a compartmentalised pig house setting with 22 pens. The introduction of virtual fences in itself already reduced EMCV spread by avoiding random mixing and for any R0<1.24 the probability to observe outbreaks affecting at least 50% of the pens(major outbreaks) remained below 0.10. When contact transmission was limited by an increasing fence effect (reducing contacts between pens), the probability to observe major outbreaks was reduced to about 0.50 for any Ro<2.7. These results indicated that pigs should not be considered the main reservoir host for EMCV in compartmentalised pig farms. Additionally, EMCV transmission in rats was experimentally quantified at R0>9.9. These findings indicated that the virus can spread and persist easily within a rat population by horizontal rat-to-rat transmission alone, which made the rat population to a potential reservoir for EMCV and a probable transmitter of EMCV into domestic pig farms. In conclusion, multiple EMCV introductions by e.g. rodents or indirect transmission routes (by manure, farmer, rodents) most probably are required to explain major outbreaks divided over many pens in commercial pig houses. Therefore the observed (temporary) emergence of EMCV in domestic pig farms most likely had a multi factorial cause mediated by the EMCV-strain type involved, the infection status of local rodent populations, the contact structure between local rodent populations and domestic pigs and individual pig factors (susceptibility due to age or breed). To prevent or control future EMCV outbreaks in pig farms, farmers should avoid contacts between potentially infected rodent populations (active rodent control), maintain high levels of bio security and isolate diseased pigs immediately.
    Valse meeldauw: een probleem in de zomerbloementeelt
    Hal, J.A. van; Vries, R. de; Meijer, D.A. ; Bos, F. ; Helm, F.P.M. van der; Wurff, A.W.G. van der - \ 2008
    Gewasbescherming 39 (2008)1. - ISSN 0166-6495 - p. 1 - 2.
    bloementeelt - snijbloemen - peronospora farinosa - onderzoek - infectieziekten - ziektepreventie - rotaties - hygiëne - vragenlijsten - gewasbescherming - zomerteelt - wetenschappelijk onderzoek - zomerbloemen - floriculture - cut flowers - peronospora farinosa - research - infectious diseases - disease prevention - rotations - hygiene - questionnaires - plant protection - summer cultivation - scientific research - summer flowers
    Valse meeldauw is een toenemend probleem in de zomerbloementeelt. Onderzoek naar de biologie van valse meeldauw is op dit moment noodzakelijk om effectieve aangrijpingspunten voor bestrijding te vinden. WUR Glastuinbouw verricht onderzoek naar bestrijdingsmaatregelen van valse meeldauw in zomerbloemgewassen. PPO bollenteelt, boomkwekerij en fruit (PPO-BBF) doet onderzoek naar de biologie van en beheersmaatregelen tegen valse meeldauw in zonnebloemen
    Vaccinatieschema leghennen: kan er iets uit?
    Wagenaar, J.P. - \ 2007
    BioKennis bericht Pluimveevlees & eieren 2 (2007). - 4 p.
    pluimveehouderij - diergezondheid - vaccinatie - verplichte vaccinatie - hennen - infectieziekten - poultry farming - animal health - vaccination - mandatory vaccination - hens - infectious diseases
    Het is gebruikelijk dat leghennen, ook biologische, tijdens de opfok 20 keer een vaccin toegediend krijgen. Jonge hennen reageren hier soms hevig op waarbij (de indruk bestaat dat) na sommige entingen minder voer wordt opge nomen. Opfokhennen bereiken moeilijker het norm gewicht. In de biologische veehouderij wil men op meer natuurlijke wijze de afweer tegen ziekten vergroten. De vraag hierbij is of minder vaccinaties mogelijk zijn. De vaccinatie tegen NCD is de enige enting die wettelijk verplicht is, de rest is vrijwillig. Om meer inzicht te krijgen in de effecten van vaccinaties en de noodzaak ervan, zijn op 5 opfokbedrijven totaal 20 koppels gevolgd.
    Epidemiological analysis of the 2006 bluetongue virus serotype 8 epidemic nin North-Western Europe : distribution and dynamics of vector species
    Elbers, A.R.W. ; Mintiens, K. ; Gerbier, G. ; Spek, A.N. van der; Meroc, E. ; Zientara, S. ; Rijn, P.A. van - \ 2007
    [S.l.] : S.n. - 9
    schapenhouderij - veehouderij - bluetonguevirus - infectieziekten - dierziekten - besmetting - epidemiologische onderzoeken - nederland - belgië - frankrijk - sheep farming - livestock farming - bluetongue virus - infectious diseases - animal diseases - contamination - epidemiological surveys - netherlands - belgium - france
    For the development of surveillance programs in the aftermath of the epidemic it is important to know what is to be expected on the distribution of infection within livestock herds. Livestock herds are epidemiological units within geographical compartments in a country from which (sentinel) animals are sampled to determine the infection status. Sample size calculations to detect to disease or estimate prevalence of disease are dependent on the a priori prevalence of disease to be expected after introduction into a animal herd. The objective of this investigation was to describe the distribution of laboratory confirmed infection (serology and PCR) in infected cattle and sheep herds in the affected countries France, Belgium and the Netherlands
    Aangifteplichtige visziekten, deel 3: VHS, IHN en ISA
    Haenen, O.L.M. ; Engelsma, M.Y. - \ 2007
    Aquacultuur 22 (2007)5. - ISSN 1382-2764 - p. 33 - 37.
    aquacultuur - europese unie - richtlijnen (directives) - dierziekten - visziekten - virusziekten - infectieziekten - symptomen - diagnose - preventie - salmonidae - aquaculture - european union - directives - animal diseases - fish diseases - viral diseases - infectious diseases - symptoms - diagnosis - prevention - salmonidae
    De nieuwe aquacultuurrichtlijn 2006/88/EG, die in de herfst van 2006 is goedgekeurd door het Europese Parlement bevat een lijst van aangifteplichtige vis-, schaal- en schelpdierziekten. In dit artikel wordt ingegaan op drie virusziekten van salmoniden, te weten VHS, IHN en ISA, waarvan alleen VHS tot nu toe in Nederland is aangetoond. Alle drie de virussen zijn onschadelijk voor de mens
    Foot and mouth disease virus in different host species; the effect of vaccination on transmission
    Orsel, K. - \ 2007
    Utrecht University. Promotor(en): Mart de Jong; J.A. Stegeman, co-promotor(en): A. Bouma. - Utrecht : Universiteit Utrecht - ISBN 9789039345443 - 140
    rundveehouderij - varkenshouderij - schapenhouderij - mond- en klauwzeer - infectieziekten - virusziekten - vaccinatie - experimentele infectie - cattle husbandry - pig farming - sheep farming - foot and mouth disease - infectious diseases - viral diseases - vaccination - experimental infection
    Foot and mouth disease (FMD) is a contagious disease, affecting important livestock species like cattle, sheep and pigs. Therefore, FMD is listed as a notifiable disease to the Office International des Epizooties. The outbreaks of FMD in Europe in 2001 triggered the discussion about the use of vaccination as an additional control measure. The aim of vaccination during an epidemic of FMD is to stop virus transmission among animals or between herds. The main purpose of the work presented in this thesis was to quantify the efficacy of vaccination against FMDV in cattle, sheep and pigs, and to compare virus excretion and virus spread before clinical signs become apparent in vaccinated and non-vaccinated populations of the three host species. Transmission was quantified with reproduction ratio R, i.e. the expected number of secondary cases produced by a typical infected individual during its entire period of infectiousness in a completely susceptible population. With a reproduction ratio significantly below 1, no major outbreaks are likely to occur. Also, the size of an outbreak on a herd to be expected at the moment of first detection of clinical signs was estimated. Differences were observed between vaccine efficacy in the various species. In vaccinated calves R was significantly below 1. In vaccinated dairy cows no transmission was observed. In sheep, R was estimated below 1, although not significantly. Limited vaccine effectiveness in pigs was found; R was estimated above 1. When the vaccination capacity is limited, these findings indicate that a differentiated vaccination programme for various species might be applied. At the moment of clinical detection, most infected individuals can be expected in a pig herd. Combined with the limited vaccine efficacy priority might best be given to culling of pig herds
    Adolf Mayer (1843-1942) en zijn betekenis voor de Virologie als wetenschap
    Vlak, J.M. - \ 2007
    Gewasbescherming 38 (2007)3. - ISSN 0166-6495 - p. 81 - 85.
    virologie - tabaksmozaïekvirus - virussen - infectieziekten - plantenziekteverwekkers - virology - Tobacco mosaic virus - viruses - infectious diseases - plant pathogens
    In 2007 is het 125 jaar geleden dat Adolf Mayer voor het eerst zijn baanbrekend werk over het besmettelijk karakter van mozaiekziekte van tabak publiceerde (Mayer, 1882). Deze publicatie, in het Nederlands, in het Groningse Tijdschrift voor Landbouwkunde, markeert het begin van de virologie als wetenschapsgebied zowel nationaal als internationaal. Dit 125 jarig jubileum van de publicatie van Mayer valt samen met het vijftigjarig bestaan van de leerstoelgroep Virologie van Wageningen Universiteit. Tevens is dit een goede gelegenheid om te laten zien dat de activiteiten van de huidige leestoel Virologie voortbouwen op de bevindingen van Mayer
    Emerging pests and vector-borne diseases in Europe: Ecology and control of vector-borne diseases Volume 1
    Takken, W. ; Knols, B.G.J. - \ 2007
    Wageningen : Wageningen Academic Publishers (Ecology and control of vector-borne diseases vol. 1) - ISBN 9789086860531 - 500
    ziekten overgebracht door vectoren - plagen - infectieziekten - humane ziekten - dierziekten - ecologie - plagenbestrijding - ziektepreventie - epidemiologie - europa - globalisering - klimaatverandering - vector-borne diseases - pests - infectious diseases - human diseases - animal diseases - ecology - pest control - disease prevention - epidemiology - europe - globalization - climatic change
    This book provides examples of the most likely pests and diseases affecting man and animals in Europe, with emphasis on ecological factors favouring these diseases and methods for prevention and intervention.
    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
    Toepassingsmogelijkheden van schuim voor het doden van pluimvee = Application of foam for emergency depopulation of poultry farms
    Gerritzen, M.A. - \ 2007
    Lelystad : Animal Sciences Group (Rapport / Animal Sciences Group 37) - 10
    infectiebestrijding - infectieziekten - ziektebestrijding - infectiviteit - intensieve veehouderij - uitbraken (ziekten) - pluimveehouderij - infection control - infectious diseases - disease control - infectivity - intensive livestock farming - outbreaks - poultry farming
    Culling animals is an important instrument in fighting infectious animal diseases. To prevent the spread of infectious diseases filling a poultry house with foam is a possible alternative to depopulating the house with CO2 gas
    Characteristics of Organic Pig Production and risk analysis concerning Toxoplasma infection
    Kijlstra, A. ; Cornelissen, J.B.W.J. ; Meerburg, B.G. - \ 2007
    biologische landbouw - varkenshouderij - infectieziekten - toxoplasma - diergezondheid - voedselveiligheid - organic farming - pig farming - infectious diseases - animal health - food safety
    A short written questionnaire was used to study certain characteristics of the organic pig production chain in The Netherlands and the circumstances on the farm that might play a role in the transmission of Toxoplasma infection to the pigs. Of the 81 certified organic slaughter pig farmers present in the Netherlands in 2006, 52 responded to the questionnaire (64 % response). The farms could be divided into two populations. One population was represented by small organic pig farms with a mean number of 55 slaughtered pigs per year. These farms covered 40% of the total number of investigated farms, but only represented 2.5 % of the total number of slaughtered pigs. The second population had a mean annual production of 1460 animals. Almost 95% of these animals are currently slaughtered and further distributed by the Vion Food Group (de Groene Weg). A small part of the pigs (4%) is directly delivered to a slaughter company in Germany (Thönes) and 1% is sold via farm home sales. For each farm an arbitrary Toxoplasma risk factor analysis was performed. Factors included the type of outdoor run (concrete or soil), feeding goat or sheep whey, number of cats, access of cats to outdoor run, stables and feed, rodent control and covering roughage fed to the animals. Calculation of the total risk score (summation of chance times severity scores for several factors) showed that many farmers already used management factors that decreased the risk for Toxoplasma infection. Analysis of a possible relation between risk score and farm size showed that a poor score was often seen on small farms. Because these farms mainly sell their meat in a frozen condition via home sales, this is not considered to represent a problem for food safety. Further research is needed to investigate whether the risk for Toxoplasma can be maintained via on farm prevention or whether a Toxoplasma monitoring program should be implemented at slaughter, possibly with post slaughter decontamination. The fact that a recent report by the RIVM on food related infections has concluded that Toxoplasmosis has a markedly higher disease burden than Campylobacter or Salmonella, emphasizes the priority this subject should be given on the research agenda.
    Predicting future costs of High-Pathogenicity Avian Influenza epidemics: large versus small uncertainties
    Meuwissen, M.P.M. ; Boven, R.M. van; Hagenaars, T.H.J. ; Boender, G.J. ; Nodelijk, G. ; Jong, M.C.M. de; Huirne, R.B.M. - \ 2006
    NJAS Wageningen Journal of Life Sciences 54 (2006)2. - ISSN 1573-5214 - p. 195 - 205.
    pluimveehouderij - scharrelhouderij - batterijhuisvesting - infectieziekten - aviaire influenza A-virussen - aviaire influenzavirussen - kosten - financieel landbouwbeleid - risicoschatting - modellen - poultry farming - free range husbandry - battery husbandry - infectious diseases - avian influenza A viruses - avian influenza viruses - costs - agricultural financial policy - risk assessment - models
    Every five years, the Dutch government and the poultry sector agree on how the direct costs of epidemics in poultry, should they occur, will be shared. In the agreement for 2005¿2009 the maximum amount to be paid by the poultry sector was set considerably higher than in the 1999¿2004 agreement. This increase was caused mainly by the expected financial risks associated with High-Pathogenicity Avian Influenza (HPAI) epidemics. In this paper we focus on elucidating the uncertain and the less uncertain aspects of the HPAI financial risk problem. We distinguish between (1) the probability of an introduction of HPAI in the Netherlands, (2) the transmission potential of HPAI in the Netherlands, and (3) the costs and financing issues resulting from HPAI epidemics. We argue that whereas current understanding allows relatively precise answers to the question `If there is an there is an epidemic, how many farms will be affected and what will be the direct costs?¿, much larger uncertainties are associated with the questions `What is the chance of an HPAI epidemic in the Netherlands?¿, `How large will be the long-term government share in the direct costs?, and `How large will be the indirect costs?
    Cats and Goat Whey Associated with Toxoplasma gondii Infection in Pigs
    Meerburg, B.G. ; Riel, J.W. van; Cornelissen, J.B.W.J. ; Kijlstra, A. ; Mul, M.F. - \ 2006
    Vector-Borne and Zoonotic Diseases 6 (2006)3. - ISSN 1530-3667 - p. 266 - 274.
    biologische landbouw - dierhouderij - varkenshouderij - diergezondheid - zoönosen - infectieziekten - toxoplasma gondii - organic farming - animal husbandry - pig farming - animal health - zoonoses - infectious diseases - toxoplasma gondii - production systems - swine - milk - transmission - farms - mice
    In organic livestock production systems, farm-management factors are thought to play an important role in the on-farm prevalence of Toxoplasma gondii. Serological results and the results of an HACCP analysis were combined to determine important risk factors for the prevalence of this protozoan parasite. Mathematical analysis demonstrated that feeding goat whey to pigs and the presence of a high number of cats were positively correlated to T. gondii seroprevalence in pigs. Not covering roughage and the farmers' assumption that pigs can come into contact with cat feces also showed a positive relationship. In order to decrease the risk of T. gondii infecting their pigs, farmers should limit the access and number of cats on their farms and refrain from feeding goat whey to their pigs.
    Pro-active approaches to the identification of emerging risks in the food chain: Retrospective case studies.
    Hagenaars, T.H.J. ; Elbers, A.R.W. ; Kleter, G.A. ; Kreft, F. ; Leeuwen, P. van; Waalwijk, C. ; Hoogenboom, L.A.P. ; Marvin, H.J.P. - \ 2006
    Lelystad : Animal Sciences Group (Report ASG 06-I01112) - 64
    voedselketens - veehouderij - dierhouderij - voedselveiligheid - diergezondheid - infectieziekten - risicovermindering - risicofactoren - crises - gevalsanalyse - food chains - livestock farming - animal husbandry - food safety - animal health - infectious diseases - risk reduction - risk factors - crises - case studies
    In this report six case studies are carried out on food-safety and animal-health crises that have occurred in the recent past. The aim is to learn from these cases if and how the identification of emerging food-safety (and animal-health) risks can be improved by adopting a (more) pro-active approach
    Outdoor ranging of poultry: a major risk factor for the introduction and development of high pathogenicity Avian Influenza
    Koch, G. ; Elbers, A.R.W. - \ 2006
    NJAS Wageningen Journal of Life Sciences 54 (2006)2. - ISSN 1573-5214 - p. 179 - 194.
    pluimveehouderij - scharrelhouderij - infectieziekten - aviaire influenza A-virussen - wilde vogels - volksgezondheid - migratie - epidemiologie - epidemieën - fylogenie - bioveiligheid - poultry farming - free range husbandry - infectious diseases - avian influenza A viruses - wild birds - public health - migration - epidemiology - epidemics - phylogeny - biosafety - a viruses - british-columbia - sentinel ducks - wild ducks - hemagglutinin - waterfowl - outbreak - h7n7 - surveillance - minnesota
    High-Pathogenicity Avian Influenza (HPAI) is an extremely infectious viral disease of poultry. Public health concerns were raised when six persons died in Hong Kong in 1997 after exposure to HPAI-infected poultry. Its danger became imminent in the recent HPAI epidemic in South-East Asia when the virus expanded its geographical range via parts of central Asia to Europe, Africa and the Middle East. Wild birds are frequently carriers of influenza A viruses. Nearly all Avian Influenza (AI) viruses isolated from wild birds are low-pathogenic and cause no clinical problems in these birds. Only after low-pathogenicity viruses are introduced in poultry, in particular in chickens and turkeys, high-pathogenicity mutants emerge after a variable length of time. Biosecurity is the first line of defence against an introduction of AI into commercial poultry flocks. Any conceivable contact between possibly contaminated animals, areas around poultry houses contaminated with faecal material from wild birds and contaminated abiotic vectors on the one hand and domestic poultry on the other must be avoided. In this paper we shall discuss the worldwide occurrence of HPAI outbreaks, the existence of AI virus infections in wild birds, and possible strategies to reduce the risk of the introduction of AI viruses into domestic poultry flocks, with special reference to free ranging
    Besmettingsrisico's tussen vrijlevende en gehouden hoefdieren
    Groot Bruinderink, G.W.T.A. ; Lammertsma, D.R. - \ 2006
    De Levende Natuur 107 (2006)1. - ISSN 0024-1520 - p. 4 - 7.
    dierziekten - infectieziekten - rundvee - begrazing - wild - veehouderij - animal diseases - infectious diseases - cattle - grazing - wildlife - livestock farming
    Sinds de jaren tachtig is het aantal runderen, paarden en schapen in natuurterreinen flink toegenomen. Vanuit de veehouderij kijkt men met argwaan naar deze ontwikkelingen vanwege mogelijke overdracht van veeziekten. Omgekeerd is men vanuit de natuurbescherming bang voor een besmetting vanuit de veehouderij. Dit artikel gaat verder in op infectieziekten bij hoefdiersoorten en de epidemiologie
    Transmission of avian influenza (H7N7) in vaccinated pheasants (Chrysolophus pictus) and ducks (Callonetta leycophrys)
    Goot, J. van der; Katsma, W.E.A. ; Koch, G. ; Jong, M.C.M. de; Boven, R.M. van - \ 2005
    Lelystad : Animal Sciences Group (Report / Animal Sciences Group ASG05/101764) - 24
    aviaire influenzavirussen - fazanten - watervogels - pluimvee - hobby's - vaccinatie - preventie - onderzoek - infectieziekten - avian influenza viruses - pheasants - waterfowl - poultry - hobbies - vaccination - prevention - research - infectious diseases
    In 2003 heeft in Nederland een grote uitbraak plaatsgevonden van een hoogpathogeen aviair influenzavirus (subtype H7N7). De epidemie heeft aanzienlijke economische verliezen tot gevolg gehad, en de praktijk van grootschalige ruimingen heeft geleid tot fundamentele ethische vragen. Naast de economische verliezen en ethische vragen heeft de epidemie ook aanzienlijke negatieve sociale gevolgen gehad, niet alleen voor de commerciële pluimveehouders als ook voor meer dan 17000 houders van niet-commercieel gehouden vogels. Dit onderzoek is er op gericht om de vraag te beantwoorden of vaccinatie van niet-gedomesticeerde, hobbymatig gehouden watervogels en fazanten vanuit epidemiologisch oogpunt een effectieve controlestrategie zou kunnen zijn bij het voorkómen van infectie met hoogpathogeen aviair influenzavirus, en bij het voorkómen van het spreiden van virus van dier tot dier
    Campylobacter as a venereal disease in cattle
    Dijkstra, T. ; Wagenaar, J.A. ; Visser, I.J. ; Bergen, M.A.P. van; Pastoor, P.W. ; Strampel, J. ; Kock, P.A. - \ 2005
    Tijdschrift voor Diergeneeskunde 130 (2005)13. - ISSN 0040-7453 - p. 407 - 408.
    campylobacter fetus - infectieziekten - dierveredeling - zoogkoeien - vruchtbaarheid - rundvee - diergeneeskunde - campylobacter fetus - infectious diseases - animal breeding - nurse cows - fertility - cattle - veterinary science - fetus
    Since the introduction of AI, venereal diseases caused by Tritrichomonas fetus and Campylobacter fetus subsp. venerealis haved been eradicated in The Netherlands. Campylobacter fetus subsp. fetus can cause sporadic abortion and early embryonic death. When natural breeding is practised, venereal diseases must be included in the list of differential diagnoses of fertility problems. A case study of a Campylobacter fetus subsp. fetus infection is described.
    Gespuis in de nacht : bloedluizen: wees er op tijd bij
    Fiks, T.G.C.M. ; Emous, R.A. van; Mul, M.F. - \ 2004
    De Pluimveehouderij 34 (2004)25. - ISSN 0166-8250 - p. 19 - 19.
    vedermijten - dermanyssus gallinae - infectieziekten - pluimveehouderij - dierziektepreventie - feather mites - dermanyssus gallinae - infectious diseases - poultry farming - animal disease prevention
    Bloedluizen (vogelmijten) zijn een groot probleem in de legpluimveehouderij. Om explosieve vermeerdering te voorkomen is tijdig ingrijpen noodzakelijk. PV is een onderzoek gestart en houdt o.a. een enquete onder alle Nederlandse legpluimveehouders
    Dubbelinfecties van bacteriën en virussen bij vis : verder kijken dan je neus lang is loont
    Haenen, O.L.M. - \ 2004
    Aquacultuur 19 (2004)3. - ISSN 1382-2764 - p. 30 - 31.
    koi - visziekten - vissen - diagnostische technieken - diagnose - symptomen - infectieziekten - bacterieziekten - virusziekten - infecties - ziektebestrijding - koi - fish diseases - fishes - diagnostic techniques - diagnosis - symptoms - infectious diseases - bacterial diseases - viral diseases - infections - disease control
    Aan de hand van twee praktijkvoorbeelden van dubbelinfecties met bacteriën bij koi en met virussen bij paling wordt aangetoond dat het bij diagnostiek en onderzoek van visziekten van belang is om te zoeken naar meer dan één oorzaak. Ook voor de behandeling is dit belangrijk, bijvoorbeeld bij een combinatie van bacterie- en virusinfecties. Bij een dergelijke dubbelinfectie is het advies: geen antibiotica gebruiken maar de watertemperatuur veranderen naar een waarde die ongunstig is voor het virus en gunstig voor de vis
    Bedreigen virussen de palingpopulatie?
    Ginneken, V.J.T. van; Thilart, G. van den; Haenen, O.L.M. - \ 2004
    Aquacultuur 19 (2004)5. - ISSN 1382-2764 - p. 26 - 29.
    anguilla - palingen - visziekten - virussen - virusziekten - infectieziekten - infectie - infecties - incidentie - epidemiologie - migratie - ziektedistributie - besmetting - hematologie - bloed - bloedsamenstelling - hematocriet - aspartaat aminotransferase - lactaat dehydrogenase - eiwit - eiwitten - experimenten - anguilla - eels - fish diseases - viruses - viral diseases - infectious diseases - infection - infections - incidence - epidemiology - migration - disease distribution - contamination - haematology - blood - blood composition - haematocrit - aspartate aminotransferase - lactate dehydrogenase - protein - proteins - experiments
    Resultaten van een onderzoek naar het voorkomen van virussen (EVEX, Eel Virus European X; HVA, Herpes Virus Anguillea; EVE, Eel Virus European) bij palingen afkomstig uit diverse landen (zowel wilde paling als paling van kwekerijen) en van een zwemexperiment met geïnfecteerde en niet-geïnfecteerde palingen. Na voltooiing van de zwemreis werd in beide groepen het bloedbeeld onderzocht op diverse parameters (o.a. op hematocriet, het aantal rode bloedcellen). De resultaten zijn zeer verontrustend, omdat ze een aanwijzing vormen dat virus-infectie ertoe leidt dat palingen hun migratie naar de paaigronden niet kunnen voltooien door bloedarmoede, een beschadigde lever en een tekort aan eiwitten. Dit kan mede een oorzaak zijn voor het wereldwijd teruglopen van de palingstand
    Foot and Mouth Disease. New values, innovative research agendas and policies
    Zijpp, A.J. van der; Braker, M.J.E. ; Eilers, C.H.A.M. ; Kieft, H. ; Vogelzang, T.A. ; Oosting, S.J. - \ 2004
    Wageningen : Wageningen Academic Publishers (EAAP technical series no. 5) - ISBN 9789076998275 - 69
    mond- en klauwzeer - vee - infectieziekten - epidemieën - ziektebestrijding - crises - evaluatie - analyse - waarden - perceptie - landbouwbeleid - onderzoek - nederland - maatregelen - foot and mouth disease - livestock - infectious diseases - epidemics - disease control - crises - evaluation - analysis - values - perception - agricultural policy - research - netherlands - measures
    A Foot and Mouth Disease outbreak is not by definition similar to a Foot and Mouth Disease crisis. Why then did the 2001 outbreak result in a crisis situation in the Netherlands? It was not because nobody was prepared for it. The Ministry of Agriculture, Nature Management and Fisheries had a scenario in stock.The scenario was applied as intended. The scenario did what it was supposed to do: it prevented the spreading of the disease, it resulted in a relatively soon eradication of the disease and it minimised damage to agricultural exports. Nevertheless, the crisis was there. “Foot and Mouth Disease: new values, innovative research agenda’s and policies” reports a process in which individuals and groups involved in the crisis participated in a joint analysis of what caused the crisis, and in the making of a policy and research agenda. The conclusion was that ignorance of the societal function of animals and countryside was the cause of the crisis: the scenario focussed on Foot and Mouth Disease control in a production-oriented environment. In reality many people perceived that the scenario and its rigid application threatened nonproduction values such as the companion role of animals and the recreation function of the landscape. Inevitably a next outbreak of Foot and Mouth Disease will occur.However, research and policy makers should seriously take up this perception of animals and countryside to prevent an outbreak of becoming a deep crisis again.
    Infections with helminths and/or protozoa in cats in animal shelters in the Netherlands
    Robben, S.R. ; Nobel, W.E. le; Dopfer, D.D.V. ; Hendrikx, W.M. ; Boersema, J.H. ; Fransen, F. ; Eysker, M. - \ 2004
    Tijdschrift voor Diergeneeskunde 129 (2004)1. - ISSN 0040-7453 - p. 2 - 6.
    katten - gezelschapsdieren - protozoëninfecties - protozoa - helminthosen - kattenziekten - infectieziekten - cats - pets - protozoal infections - protozoa - helminthoses - cat diseases - infectious diseases - dogs
    To determine the prevalence of infections with helminths and protozoa in cats in animal shelters, faecal samples from 305 cats from 22 animal shelters in the Netherlands were examined, using a centrifugation-sedimentation-flotation-technique. The association between potential risk factors and the occurrence of an infection was also tested. Infections with helminths and/or protozoa were found in 160 samples (52.5%). Toxocara cati was found in 86 cats (28.2%), Cystoisospora felis in 59 cats (19.3%), Cystoisospora rivolta in 43 cats (14.1%), Capillaria spp. in 34 cats (11.2%), Ancylostoma tubaeforma in 9 cats (3.0%), Taenia taeniaeformis in 9 cats (3.0%), Aelurostrongylus abstrusus in 8 cats (2.6%), Giardia intestinalis in 3 cats (1.0%), Dipylidium caninum in 2 cats (0.7%) and Toxoplasma gondii in 1 cat (0.3%). The highest prevalence was seen in kittens and stray cats. The main preventive factor against infection was a short stay in a shelter.
    Infections with endoparasites in dogs in Dutch animal shelters
    Nobel, W.E. le; Robben, S.R. ; Dopfer, D.D.V. ; Hendrikx, W.M. ; Boersema, J.H. ; Fransen, F. ; Eysker, M. - \ 2004
    Tijdschrift voor Diergeneeskunde 129 (2004)2. - ISSN 0040-7453 - p. 40 - 44.
    honden - gezelschapsdieren - infectieziekten - parasitosen - hondenziekten - dogs - pets - infectious diseases - parasitoses - dog diseases - netherlands - toxocara
    Faecal samples from 224 dogs from 23 animal shelters in the Netherlands were examined for endoparasites. In total 20.5% of the faecal sample were positive for helminth and/or protozoa infections. Eggs of Toxocara canis were found in 8.5% of the faecal samples. Other endoparasites found were Toxascaris leonina (0.5%), Trichuris vulpis (4.9%), Uncinaria stenocephala (2.2%), Dipylidium caninum (1.3%), Taenia spp. (0.5%), Cystoisospora canis (1.3%), and C. ohioensis (1.3%). Dogs younger than 1 year and stray dogs showed the highest prevalence of infection. T. vulpis was found more often in dogs from shelters with a high cleaning frequency.
    Voorkomen van verspreiding van ziektekiemen en milieu-emissies via luchtreiniging
    Aarnink, A.J.A. ; Landman, W.J.M. ; Melse, R.W. ; Gijsel, P. de; Huynh Thi Thanh Thuy, ; Fabri, T. - \ 2004
    Wageningen : Agrotechnology & Food Innovations (Rapport / Agrotechnology & Food Innovations nr. 059) - ISBN 9789067547451 - 63
    veehouderij - dierhouderij - huisvesting, dieren - infectieziekten - luchtverontreinigende stoffen - besmetters - emissie - infectie door luchtdeeltjes - livestock farming - animal husbandry - animal housing - infectious diseases - air pollutants - contaminants - emission - airborne infection
    Waterberging op landbouwgronden : effecten op plant- en dierziekten, onkruiden en contaminanten
    Cornelissen, A.H.M. ; Harmsen, J. ; Kempenaar, C. ; Knol, W.C. ; Zweerde, W. van der - \ 2003
    Utrecht : Stowa (STOWA rapport 2003 19) - 76
    wateropslag - waterbeheer - landbouw - diergezondheid - besmetters - waterverontreiniging - hoogwaterbeheersing - plantenziekten - landbouwgrond - nederland - infectieziekten - water storage - water management - agriculture - animal health - contaminants - water pollution - flood control - plant diseases - agricultural land - netherlands - infectious diseases
    In deze studie zijn met een quick scan deze effecten van waterberging onderzocht. Het accent ligt daarbij op het regionale watersysteem. Daarvoor is een inventarisatie uitgevoerd van bestaande kennis bij deskundigen en is de literatuur verkend. Het accent in deze studie ligt op die stoffen en organismen die in de melkveehouderij en akkerbouw risicovol zijn. Het blijkt dat er nog niet eerder gericht onderzoek is verricht naar de relatie tussen waterberging en plant- en dierziekten. Kennis over effecten van waterberging op contaminanten is vooral ontleend aan onderzoek in het rivierengebied. Van alle relevante contaminanten (zware metalen, PAK's etc.), plant- en dierziekten en onkruiden is aangegeven door welke omstandigheden ze worden beïnvloed, welke processen er in de bergingsgebieden spelen en wat de effecten zijn op gewassen en vee
    Development of a novel subunit vaccine against East Coast fever based on the Theileria parva sporozoite surface protein p67
    Kaba, S.A. - \ 2003
    Wageningen University. Promotor(en): Just Vlak; R.W. Goldbach, co-promotor(en): Monique van Oers. - [S.l.] : S.n. - ISBN 9789058088895 - 120
    theileria parva - rundvee - protozoëninfecties - sporozoïten - oppervlakteantigenen - vaccinontwikkeling - infectieziekten - theileria parva - cattle - protozoal infections - sporozoites - surface antigens - vaccine development - infectious diseases
    Theileriaparva is an intracellular protozoan parasite and the causative agent of a lethal cattle disease, called East Coast fever (ECF). This disease poses a major constraint on improvement of cattle production in Eastern, Central andSouthern Africa, especially for smallholder farmers. The protozoa are transmitted to cattle in the form of sporozoites by the brown-ear tick, Riphicephalus appendiculatus . The sporozoites invade lymphocytes, where they develop into schizonts. In addition, they induce a large-scale uncontrolled proliferation of the lymphocytes, leading to severe clinical symptoms, like weight loss, pyrexia, anaemia, terminal respiratory distress and finally death ensues within two to three weeks, if the animal is not treated. The disease can be cured with antibiotics, and this is the basis for the current method of vaccination, called "Infection and Treatment", where animals are injected with T. parva sporozoites and are, simultaneously, treated with antibiotics over a longer period of time. This vaccination method, however, is far from convenient, since the production of large amounts of sporozoites is very time consuming and a cold environment is needed to keep the sporozoites alive. In addition, the use of a live vaccine has pertinent risks, especially when the instructions for antibiotic treatment are not strictly followed and the immunity engendered is strain-specific. 

    The research described in this thesis was aimed at the possibilities of developing a subunit vaccine against East Coast fever, based on the production of T. parva sporozoite surface major protein p67. This protein is present on the outside of sporozoites and plays a crucial role in the entry of sporozoites into lymphocytes and is the major antigen producing neutralising antibodies. The first objective was to produce large amounts of p67 in a near-authentic conformation. Production of recombinant p67 in bacterial expression systems had failed to produce correctly processed protein and large amounts were needed to achieve a reasonable (70 %) level of protection. The baculovirus-insect cell expression system forms a valuable alternative for the expression of large amounts of near-authentic and immunologically active proteins. Previous attempts, however, to produce p67 in insect cells resulted in low levels of recombinant protein, which had a conformation different from the native p67 protein. Again large quantities were needed to protect cattle against ECF.

    In the research described in thesis several types of novel baculovirus vectors were constructed to produce different regions of p67 in insect cells. In the first set of vectors, various domains of p67 were expressed as separate entities, but this resulted in low levels of expression. For the second set, domains of p67 were fused to the carboxy-terminus of the "green fluorescent protein" (GFP), a visible marker, leading to a considerable increase in yield of recombinant p67. In addition, GFP:p67 fusion polypeptides were recognised by a monoclonal antibody (TpM12), which was raised against native p67 and capable of neutralising sporozoites. On the contrary, only a small portion of full length, non-fused p67 expressed in insect cells was recognised by this antibody. Fusion to GFP, thus, appeared to increase the stability of p67 and to result in a more native configuration of the recombinant protein. In a third set of baculovirus vectors, N and C terminal domains of p67 were fused to the baculovirus envelope protein GP64. This resulted in the display of recombinant p67 on the outside of insect cells as well as on the surface of budded baculovirus particles. The TpM12 epitope was also conserved when p67 was fused to GP64.

    P67 could also be expressed as a secreted soluble protein. The rationale behind this experiment was to ultimately facilitate the purification of the recombinant protein. This was achieved by removal of a putative transmembrane domain and fusion of p67 to a specific signal peptide derived from honeybee melittin. Deletion of the viral genes, chitinase and v-cathepsine from the baculovirus genome enhanced the integrity and increased the stability of this secreted p67 protein. Unfortunately, the secreted form was no longer recognised by TpM12, and hence, had a conformation different from p67 in sporozoites. Therefore, the secreted p67 was not tested in further immunological studies.

    In order to select the best recombinant p67 products for extensive vaccine trials, the various fusion proteins combining domains of p67 with GFP or GP64 were tested in mice for their immunogenicity and, especially, the ability to induce neutralising antibodies. In mice, the p67 molecule, lacking both its signal peptide and transmembrane region, and fused to GFP (GFP:p67ΔSS) gave the best humoral immune response, followed by the p67 C-terminal domain coupled to GP64 (GP64:p67C). These two immunogens were tested in cattle, in combination with a water-in-oil or a saponin-based adjuvant. Also in cattle, a high level of sero-conversion was obtained using a total of 100 µg recombinant p67 for immunisation divided over two needle injections. Moreover, the antisera raised in mice and cattle neutralised the infectivity of T. parva sporozoites in an in-vitro assay. Subsequently, in Kenya Boran cattle were vaccinated with GFP:p67DSS or with GP64-p67C. After a primary immunisation followed by a single booster, T. parva stabilated sporozoites were injected to test whether the vaccines protected the animals from ECF. Eighty five percent of the animals was protected from the lethal disease (ECF) using a much lower dose of recombinant protein than was used in the earlier studies.

    The research described in this thesis exploited the versatility of the baculovirus-insect cell expression system and showed that an ECF subunit vaccine based on recombinant p67, in a better conformation and formulated in an optimal adjuvant, can be used effectively in a vaccination program. Both of the proteins tested are good candidates for the development of a commercial ECF subunit vaccine and may contribute substantially to improvement in cattle productivity and poverty alleviation in sub-SaharanAfrica

    Bouwstenen voor beleid : pluimveehouderij en besmettelijke dierziekten, inventarisatie van kennis en dilemma's
    Hartog, L.A. den; Leenstra, F.R. ; Enting, I. ; Meeuwissen, M. ; Schrijver, R. ; Hermans, T. - \ 2003
    Wageningen : Wageningen University - 32
    pluimvee - pluimveehouderij - infectieziekten - aviaire influenzavirussen - kennis - bedrijfssystemen - ziektepreventie - ziektebestrijding - nederland - maatregelen - poultry - poultry farming - infectious diseases - avian influenza viruses - knowledge - farming systems - disease prevention - disease control - netherlands - measures
    Het rapport geeft een samenvattend overzicht van de bij Wageningen UR beschikbare kennis over pluimveehouderij en besmettelijke dierziekten die in internationaal verband worden bestreden (zgn. Lijst A ziekten). Deze kennis levert een aantal dilemma’s en discussiepunten op.
    De rekening van besmettelijke dierziekten: samenleving en bedrijven
    Meuwissen, M.P.M. ; Asseldonk, M.A.P.M. van; Huirne, R.B.M. - \ 2003
    Tijdschrift voor sociaalwetenschappelijk onderzoek van de landbouw 18 (2003)4. - ISSN 0921-481X - p. 222 - 223.
    intensieve veehouderij - dierziekten - infectieziekten - diergezondheid - landbouwkundige rampen - heffingen - totale kosten - evaluatie - financieren - intensive livestock farming - animal diseases - infectious diseases - animal health - agricultural disasters - levies - total costs - evaluation - financing
    Onderdelen van de bestaande situatie m.b.t. de intensieve veehouderij en de aanpak van besmettelijke dierziekten worden genoemd, waarna geconcludeerd wordt dat de bestaande situatie ertoe leidt dat het financieren van uitbraken uiteindelijk wel een publiek-private aangelegenheid moet blijven
    Weinig klauwproblemen op high-techbedrijf door goede controle en snel ingrijpen
    Thomassen, I. ; Kamp, A. van der - \ 2002
    Praktijkkompas. Rundvee 16 (2002)6. - ISSN 1570-8586 - p. 4 - 5.
    melkveehouderij - melkvee - melkkoeien - diergezondheid - klauwen - hoeven - infectieziekten - botziekten - agrarische bedrijfsvoering - rundveeziekten - preventie - ziektepreventie - proefbedrijven - demonstratiebedrijven, landbouw - bedrijfsvergelijking in de landbouw - proefboerderijen - dairy farming - dairy cattle - dairy cows - animal health - claws - hooves - infectious diseases - bone diseases - farm management - cattle diseases - prevention - disease prevention - pilot farms - demonstration farms - farm comparisons - experimental farms
    Regelmatige klauwcontrole, snel ingrijpen bij problemen en preventieve maatregelen zijn belangrijk, zeker op een bedrijf waar de dieren het hele jaar in de stal zijn.
    Onverwachte omslag in BVD-status high-techbedrijf
    Bloemert, J. ; Verhoeff, K. ; Kamp, A. van der - \ 2002
    Praktijkkompas. Rundvee 16 (2002)4. - ISSN 1570-8586 - p. 20 - 21.
    melkveehouderij - melkvee - diergezondheid - pestivirus - rundveeziekten - pathogeen eliminatie - certificering - infecties - infectieziekten - ziekteoverdracht - ziektebestrijding - melkveebedrijven - proefbedrijven - demonstratiebedrijven, landbouw - proefboerderijen - dairy farming - dairy cattle - animal health - pestivirus - cattle diseases - pathogen elimination - certification - infections - infectious diseases - disease transmission - disease control - dairy farms - pilot farms - demonstration farms - experimental farms
    Hoe nu verder te handelen om de vrije status terug te krijgen?
    Quantification of Actinobacillus pleuropneumoniae transmission
    Velthuis, A. - \ 2002
    Wageningen University. Promotor(en): M.C.M. de Jong; J.H.M. Verheijden; N. Stockhofe-Zurwieden. - S.l. : S.n. - ISBN 9789058086792 - 166
    varkens - actinobacillus pleuropneumoniae - transmissie - ademhalingsziekten - infectieziekten - longen - serologie - diergeneeskunde - pigs - actinobacillus pleuropneumoniae - transmission - respiratory diseases - infectious diseases - lungs - serology - veterinary science

    More insight into the transmission dynamics of bacteria between animals is gained with help of transmission experiments. In a transmission experiment various aspects of transmission can be studied. For example, more insight into the transmission dynamics can be gained, transmission can be quantified, or the effect of interventions on transmission can be quantified so that better-directed intervention strategies can be devised. The main goal of the research described in this thesis was the development of methods to quantify bacterial transmission in an experimental setting. We restricted the research to the transmission of one specific bacterium, i.e. Actinobacillus pleuropneumoniae serotype 9 in pigs. A. pleuropneumoniae is regarded as a primary pathogen that causes pleuropneumonia in pigs and brings considerable economic losses about world-wide. Direct transmission from pig to pig is believed to be the most important transmission route of this bacterium, therefore, prevention or reduction of transmission in direct animal to animal contact should in principle lead to eradication. By conducting several transmission experiments we got a better understanding of the transmission dynamics of the bacterium. It was concluded that an infectious state is related to an A. pleuropneumoniae positive tonsil at necropsy. Another conclusion was that the infectivity of a pig is a tenfold higher on days where more than ten A. pleuropneumoniae bacteria were isolated from the nasal swab than on the other days. Furthermore, new statistical and mathematical methods were developed to estimate or test hypothesis about the level of transmission. Statistical methods were based on the transient state (TS) algorithm. The TS algorithm is based on the stochastic susceptible-infectious-removed (SIR) model and provides a time-dependent probability distribution over the number of infected individuals during an epidemic. TS methods are difficult to calculate due to numerical limitations. Therefore, one would probably resort to the easily applicable but less appropriate final size (FS) methods. So, we investigated the error made when FS methods are used instead of TS methods. This error was generally not substantial. Furthermore, a new method to find a difference in transmission between two treatment groups ( MaxDiff test) has been developed and compared to tests based on FS and TS algorithms and a test based on a Generalised Linear Model (GLM). The GLM test was most powerful in finding a difference in transmission. Next were the TS test and the MaxDiff test, which were approximately equally powerful, but more powerful than the FS test especially when the R 0 in both treatment groups are larger than 1. At the end, we tested the effect of vaccination on the transmission of A. pleuropneumoniae in the newly developed experimental design. The effect of vaccination was quantified with a method based on a generalised linear model, which appeared to be most appropriate for the quantification of A. pleuropneumoniae transmission. The effect of vaccination on the susceptibility could not been demonstrated.

    Water management as a tool for malaria mosquito control? The case of the Office du Niger, Mali
    Klinkenberg, E. ; Huibers, F.P. ; Takken, W. ; Toure, Y.T. - \ 2002
    Irrigation and Drainage Systems 16 (2002)3. - ISSN 0168-6291 - p. 201 - 212.
    malaria - infectieziekten - ziektepreventie - mali - irrigatie - malaria - infectious diseases - disease prevention - irrigation - mali
    A field study was carried out in the rice irrigation scheme Office du Niger, Mali, to observe malaria mosquito larval development as related to differences in field irrigation practices, such as water level, irrigation application and irrigation frequency. The main aim was to find out to what extent field water management can be considered as a tool for vector control for this irrigation system. The results show that minor differences in water management do result in small differences in mosquito development, with respect to larval densities and species composition. The main malaria vector for the area, An. gambiae s.l., developed predominantly in the first six weeks after transplanting. Due to improper drainage after harvest An. gambiae s.l. breeding quickly re-established on fields where small water pools remained. Although further research is needed, suggestions for mosquito control in the Office du Niger would be a strict performance of the agricultural calendar in combination with a rotation of transplanting in large blocks.
    Schade verzekerd
    Hogeveen, H. ; Meuwissen, M.P.M. ; Huirne, R.B.M. - \ 2002
    Veeteelt 19 (2002)23. - ISSN 0168-7565 - p. 10 - 13.
    rundveeziekten - schade - diergeneeskunde - risicofactoren - risicoschatting - landbouwverzekering - agrarische bedrijfsvoering - infectieziekten - cattle diseases - damage - veterinary science - risk factors - risk assessment - agricultural insurance - farm management - infectious diseases
    Vanuit het gezichtspunt van de verzekeringsmaatschappijen is onderzoek verricht naar de risico's van rundveeziekten. Hierbij is een overzicht gegeven van de kans dat erop een gemiddeld melkveebedrijf in een jaar een dierziekte optreedt en een overzicht van de verzekerbaarheid van de verschillende dierziekten
    Haemocytic defence in black tiger shrimp (Penaeus monodon)
    Braak, K. van de - \ 2002
    Wageningen University. Promotor(en): E.A. Huisman; W.B. van Muiswinkel; W.P.W. van der Knaap; J.H.W.M. Rombout. - S.l. : S.n. - ISBN 9789058086518 - 159
    penaeus monodon - crustacea - garnalen - immuunsysteem - immuniteitsreactie - immuniteit - verdedigingsmechanismen - via de cel overgebrachte immuniteit - rode bloedcellen - hemolymfe - monoclonale antilichamen - experimentele infectie - infectieziekten - garnalenteelt - penaeus monodon - crustacea - shrimps - immune system - immune response - immunity - defence mechanisms - cell mediated immunity - haemocytes - haemolymph - monoclonal antibodies - experimental infection - infectious diseases - shrimp culture

    Tropical shrimp culture is one of the fastest growing aquaculture sectors in the world. Since this production sector is highly affected by infectious pathogens, disease control is nowadays a priority. Effective prevention methods can be developed more efficiently when quantitative assays for the evaluation and monitoring of the health status of shrimp are available. The defence mechanisms of crustaceans are poorly understood, but knowledge about these is a prerequisite for the development of such health parameters. Therefore, the aim of this thesis was to obtain a better understanding of the defence system of the major cultured shrimp species in the world, Penaeus monodon . The present study emphasised the cellular components of the circulatory system, which play a central role in the haemolymph defence, i.e. the haemocytes.

    To study the usefulness of haemolymph for shrimp health assessment, several cellular and humoral characteristics of P. monodon were determined after haemolymph sampling from the ventral part of the haemocoel (chapter 2). Among other things, five different haemocyte types were distinguished by light microscopy, while electron microscopy revealed granular cells, semigranular cells and hyaline cells. It was concluded that haemolymph characterisation might be a useful tool for health estimation of P. monodon , but that standardisation of the techniques is a prerequisite.

    The use of monoclonal antibodies (mAbs) was proposed as a potential approach for the characterisation of haemocytes. Therefore, a set of mAbs specific for P. monodon haemocytes was produced by immunising mice with haemocyte membrane lysates (chapter 3). Four mAbs (WSH 6, WSH 7, WSH 8 and WSH 16) were selected and extensively characterised. For all mAbs, differences in amount and intensity of the labelling were found between immediately fixed haemocytes and non-fixed cells that were kept in Alsever's solution (AS, an anticoagulant which reduces haemocyte activation) and kept in L15 cell culture medium. WSH 6 reacted with the cell membranes of all fixed haemocytes, while WSH 7 and WSH 16 reacted with the cell membranes of the majority of fixed haemocytes. The membrane labelling appeared to decrease when cells were kept in L15 medium. WSH 8 did not react with the haemocyte membranes. All mAbs reacted with some granules, mainly present in the hyaline cells, when the haemocytes were immediately fixed. When non-fixed cells were kept in AS or in L15 medium, positive granules were also observed in semigranular and granular haemocytes as well as in the largest granules of a fourth cell type, that contains many granules of different sizes and electron densities. Immuno-reactive extracellular fibrous material could be observed when cells were kept in L15 medium. The change in staining pattern was extreme for WSH 8, somewhat less for WSH 6 and WSH 7 and lowest for WSH 16. Double labelling revealed that all mAbs showed a different staining pattern on membranes as well as on granules. WSH 16 also showed labelling in cytoplasmic vesicles, as well as in haemolymph plasma on histological sections. The hypothesis was put forward that immuno-reactive molecules recognised by these mAbs, were related to haemocyte activation factors and that the mAbs could be used in studying haemocyte differentiation, behaviour and function in P. monodon shrimp. Later on, WSH 8 indeed proved suitable for this in immuno-histochemical studies.

    A better characterisation of the immuno-reactive molecules would support the interpretation of the results. In order to investigate whether the mAbs reacted with well-conserved molecules and with haemocytes in animals with molecules that were better characterised than those of P. monodon , a comparative study was carried out (chapter 4). The mAbs also reacted on haemocyte monolayers of the freshwater shrimp Macrobrachium rosenbergii and the two freshwater crayfish Procambarus clarkii and Pacifastacus leniusculus . Immuno-labelling on haemolymph monolayers of the terrestrial isopod crustacean Porcellio scaber (woodlouse) and on coelomic fluid of the annelid Lumbricus terrestris (earthworm) showed partial reactivity. Immuno-reactivity was not observed on haemolymph monolayers of the insect Spodoptera exigua (Florida moth) and the mollusc Lymnaea stagnalis (pond snail), or on blood cell monolayers of the freshwater fish Cyprinus carpio (carp) and of human. On histological sections of M. rosenbergii and P. clarkii , mAb labelling was observed on the haemolymph plasma and on a proportion of the haemocytes. This comparative study showed reactivity of the mAbs in a wide range of crustaceans and related animals and suggests that well conserved molecules were recognised, which may indicate functional importance. Later on, molecules of P. leniusculus that reacted with WSH 6 were better characterised and it was indicated that this molecule could be clotting protein or filamin, which both could be involved in coagulation processes. Unfortunately, the immuno-reactive molecules of P. monodon with WSH 8 could not be characterised further.

    The circulating haemocytes of crustaceans are generally divided into hyaline, semigranular or granular cells, however, this classification is still ambiguous. Not much is known about haemocyte production in penaeid shrimp, but for a better haemocyte classification it is useful to establish how these cells are produced and mature. In order to clarify this, the localisation and (ultra)structure of the haematopoietic tissue and its relation with the circulating haemocytes were studied in chapter 5. The haematopoietic tissue is located in many lobules dispersed in different areas in the cephalothorax, mainly at the dorsal side of the stomach and at the base of the maxillipeds. In order to study the haemocyte production and maturation, shrimp were either injected with LPS, while mitosis was inhibited by vinblastine, or were repeatedly sampled for haemolymph. The presumed precursor cells in the haematopoietic tissue were located towards the exterior of the lobules and maturing young haemocytes towards the inner part, where they can be released into the haemal lacunae. It was proposed that the presumed young haemocytes were generally known as the hyaline cells. Moreover, a new model was proposed where the hyaline cells gave rise to two haemocytic developmental series, i.e., the large- and small-granular cell line. In addition, indications were found that the granular cells of at least the large-granular cell line mature and accumulate in the connective tissue and are easily released into the haemolymph. Light and electron microscopical observations supported the regulation of the haemocyte populations in the circulation by (stored) haemocytes from the connective tissue.

    In order to investigate the clearance reaction of P. monodon haemocytes live Vibrio anguillarum bacteria were injected and the shrimp were periodically sampled (chapter 6). Immuno-double staining analysis with specific antisera against the haemocyte granules and bacteria showed that many haemocytes encapsulated the bacteria at the site of injection. Furthermore, a rapid decrease of live circulating bacteria was detected in the haemolymph. Bacterial clearance in the haemolymph was induced by humoral factors, as observed by agglutinated bacteria, and followed by uptake in different places in the body. Bacteria mainly accumulated in the lymphoid organ, where they, or their degradation products, could be detected for at least seven days after injection. The lymphoid organ consists of folded tubules with a central haemal lumen and a wall, layered with cells. The haemolymph, including the antigens, seemed to migrate from the central tubular lumen through the wall, where the bacteria are arrested and their degradation is started. The lymphoid organ of penaeids is also poorly studied. Electron microscopy of the lymphoid organ revealed the presence of many phagocytic cells that morphologically resemble small-granular haemocytes. It was proposed that haemocytes settle in the tubule walls before they phagocytose. Observations from the present study are similar to clearance mechanisms in the hepatic haemolymph vessels in most decapod crustaceans that do not possess a lymphoid organ.

    Immuno-staining suggested that many of the haemocytes degranulate in the lymphoid organ, producing a layer of fibrous material in the outer tubule wall. These findings might contribute to the reduced haemocyte concentration in the haemolymph of diseased animals or following injection of foreign material. It is proposed that the lymphoid organ is a filter for virtually all foreign material encountered in the haemolymph. Haemocyte degranulation in the lymphoid organ tubule walls could contribute to the filtering capacity of this organ.

    The experimental shrimp appeared to contain many lymphoid organ spheroids, where bacterial antigens were finally also observed. It is proposed that the spheroids have a degradation function for both bacterial and viral material, and that their presence is primarily related to the history of the infectious burden of the shrimp.

    White spot syndrome virus (WSSV) is the pathogen that is a major cause of mortality in shrimp culture in the past decade. In contrast to the extensive study of the morphology and genome structure of the viral pathogen, the defence reaction of the host during WSSV infection is hardly studied. Therefore, the haemocyte response upon experimental WSSV infection was examined in P. monodon shrimp (chapter 7). A strong decline in free circulating haemocytes was detected during severe WSSV infection. The combination of in situ hybridisation with a specific DNA probe to WSSV and immuno-histochemistry with a specific antibody against haemocyte granules was carried out on tissue sections. Haemocytic reactions have never been reported in chronic or acute viral infections in shrimp, but the present results showed that many haemocytes leave the circulation and migrate to tissues where many virus-infected cells are present. However, a subsequent response to the virus-infected cells was not detected. During virus infection, the number of cells in the haematopoietic tissue was also reduced. Moreover, it was suggested that many haemocytes degranulated in the lymphoid organ, producing a similar but more obvious layer of fibrous material in the outer tubule wall than after bacterial injection.

    The obtained results are summarised and discussed in chapter 8. Furthermore, the results described in chapters 6 and 7 were used to refine the proposed model of chapter 5. The haemocytes of the small-granular cell line are suggested to mature and carry out their function in the lymphoid organ. The results of the present research emphasise the rapid activation of the haemocytes after stimulation of the animal and illustrate several relevant functions of those cells. The present knowledge provides reliable grounds for further discussions about production, maturation and activation of the haemocytes in penaeid shrimp and possibly also in related animals like other shrimp species, crayfish, lobsters and crabs. Knowledge of the functioning of the defence system is of extreme importance since stimulation of this system is considered as a potential intervention strategy in shrimp culture to overcome the infectious diseases.

    Toxoplasma gondii infecties in de varkenshouderij : verslag van een inventariserende telefonische enquête betreffende de aanwezigheid van risicofactoren bij biologische en scharrelvarkenshouders
    Kijlstra, A. - \ 2001
    Lelystad : ID-Lelystad (Rapport / ID-Lelystad 2154) - 15
    toxoplasma gondii - toxoplasmose - infectieziekten - varkenshouderij - scharrelhouderij - biologische landbouw - interviews - risicofactoren - diergezondheid - volksgezondheid - nederland - toxoplasma gondii - toxoplasmosis - infectious diseases - pig farming - free range husbandry - organic farming - interviews - risk factors - animal health - public health - netherlands
    Per telefoon is navraag gedaan naar het voorkomen van risicofactoren als katten op het bedrijf, muizen en ratten, oppervlaktewater als drinkwater, mogelijkheden voor besmetting via het voer, en mogelijkheden voor besmetting via de uitloop van varkens.
    Resultaten praktijkproef Dierveiligheidsindex
    Mul, M.F. ; Bokma-Bakker, M.H. - \ 2001
    Lelystad : Praktijkonderzoek Veehouderij (Proefverslag / Proefstation voor de Varkenshouderij P1.255) - 99
    varkenshouderij - diergezondheid - dierenwelzijn - dierziekten - infectieziekten - agrarische bedrijfsvoering - prestatie-indexen - pig farming - animal health - animal welfare - animal diseases - infectious diseases - farm management - performance indexes
    De Dierveiligheidsindex is ontwikkeld met het doel om op het primaire bedrijf de risico’s op insleep en verspreiding van dierziekten versneld terug te dringen en het gezondheids- en welzijnsniveau versneld te verbeteren. De Dierveiligheidsindex (DVI) is een meetinstrument voor varkensbedrijven waarmee met behulp van checklists inzicht wordt verkregen in de aandachtsvelden contactstructuur, diergezondheid en dierenwelzijn. Ieder aandachtsveld is onderverdeeld in drie niveaus van oplopende zwaarte (DVI-1-, DVI-2- en DVI-3-niveau). Het DVI-niveau 1 omvat twee typen voorschriften: de basisvoorwaarden waartoe onder andere de wetgeving behoort en DVI-1-voorschriften. Er is van medio 1999 tot medio 2000 een praktijkproef uitgevoerd met als doel een indruk te krijgen van 1) de haalbaarheid van de verschillende DVI-niveaus bij aanvang van de proef, 2) de mogelijkheden om met behulp van de Dierveiligheidsindex binnen een proefperiode van circa een jaar door te groeien naar hogere niveaus van diergezondheid en dierwelzijn en 3) de praktische uitvoerbaarheid daarvan
    'Piglet snatching' in de praktijk
    Smits, H. ; Binnendijk, G. ; Eijck, I. - \ 2001
    Praktijkkompas. Varkens 15 (2001)5. - ISSN 1570-8578 - p. 12 - 13.
    biggenziekten - varkensziekten - pathogeen eliminatie - ziektepreventie - infectieziekten - scheiding - biggenverwijdering - zeugen - protocollen - piglet diseases - swine diseases - pathogen elimination - disease prevention - infectious diseases - separation - piglet removal - sows - protocols
    Piglet snatching is een goedkope methode voor het vrijmaken van een varkenspopulatie op een bedrijf van een aantal schadelijke ziekteverwekkers.
    Cranendonck versneld IBR-vrij door afvoer besmette koeien
    Hanekamp, W. ; Bleumer, E. - \ 2001
    Rundvee praktijkonderzoek 14 (2001)1. - ISSN 1569-805X - p. 26 - 27.
    rhinotracheïtis - rhinitis - infectieziekten - virusziekten - vaccinatie - ziektebestrijding - rundveeziekten - melkveehouderij - kosten-batenanalyse - economische analyse - kosten - melkvee - melkkoeien - rhinotracheitis - rhinitis - infectious diseases - viral diseases - vaccination - disease control - cattle diseases - dairy farming - cost benefit analysis - economic analysis - costs - dairy cattle - dairy cows
    Door natuurlijk verloop zijn op praktijkcentrum Cranendonck nog maar enkele dieren met afweerstoffen tegen het IBR-veldvirus.
    Preventieve maatregelen voor een gezonde bedrijfsvoering
    Hanekamp, W.J.A. ; Verhoeff, J. - \ 2000
    Lelystad : Praktijkonderzoek Veehouderij (Rapport / Praktijkonderzoek Veehouderij 193) - 18
    melkveehouderij - rundveeziekten - infectieziekten - demonstratiebedrijven, landbouw - proefbedrijven - landbouwvoorlichting - dairy farming - cattle diseases - infectious diseases - demonstration farms - pilot farms - agricultural extension
    In dit rapport zijn allereerst de kenmerken van de genoemde besmettelijke dierziekten beschreven (hoofdstuk 2) gevolgd door een opsomming en toelichting van vier hoofdmaatregelen (hoofdstuk 3). Aansluitend is aangegeven op welke manier over deze maatregelen gecommuniceerd is (hoofdstuk 4). Een afsluitende evaluatie staat aan het eind (hoofdstuk 5).
    Heckrunderen in de Oostvaardersplassen : risico voor infectieziekten of niet?
    Hessels, A.L.D. ; Poel, W.H.M. van der; Nielen, M. ; Emmerzaal, A. ; Schukken, Y.H. - \ 2000
    Tijdschrift voor Diergeneeskunde 125 (2000)2. - ISSN 0040-7453 - p. 38 - 47.
    bovidae - herkauwers - infectieziekten - diergezondheid - populaties - dierziekten - reticulo-endotheliaal systeem - risicoschatting - risicofactoren - natuurgebieden - grote grazers - zuidelijk flevoland - bovidae - ruminants - infectious diseases - animal health - populations - animal diseases - reticuloendothelial system - risk assessment - risk factors - natural areas - large herbivores - zuidelijk flevoland
    Risico-identificatie en risico-assessment werden uitgevoerd met onderbouwing van informatie over het voorkomen en over de mechanismen van diverse infectieziekten zoals in de literatuur beschreven is. Het bleek dat de betreffende runderen een low risk profile hebben. Hieruit kunnen managementmaatregelen geformuleerd worden.
    De invloed van geboorte-inductie en het tijdstip van vlekziekte-parvo-vaccinatie tijdens de zoogperiode op het interval spenen-bronst van zeugen
    Binnendijk, G. ; Vesseur, P. ; Vonk, M. - \ 1999
    Praktijkonderzoek varkenshouderij 13 (1999)1. - ISSN 1382-0346 - p. 22 - 24.
    zeugen - geboorte - zogen - oestrus - lactatieduur - drachtigheidsperiode - vaccinatie - parvoviridae - erysipelothrix - infectieziekten - sows - birth - suckling - oestrus - lactation duration - gestation period - vaccination - parvoviridae - erysipelothrix - infectious diseases
    Het effect van het al dan niet toepassen van geboorte-inductie in combinatie met het tijdstip van het toedienen van een vlekziekte-parvo-vaccinatie is onderzocht. Geboorte-inductie heeft effect op de drachtduur, het geboortegewicht van de biggen en het percentage biggen met spreidzit.
    Weinig besmettelijke dierziekten op PR proefbedrijven
    Hanekamp, W. ; Verhoeff, K. - \ 1999
    Praktijkonderzoek Rundvee, Schapen en Paarden. Praktijkonderzoek 12 (1999)1. - ISSN 1386-8470 - p. 20 - 21.
    dierpathologie - melkvee - proefbedrijven - infectieziekten - ziektebestrijding - ziektepreventie - animal pathology - dairy cattle - pilot farms - infectious diseases - disease control - disease prevention
    In twee jaar tijd is door natuurlijk verloop het percentage met IBR besmette dieren gehalveerd. De meeste proefbedrijven hebben voor Paratbc de onverdachtstatus 6. Eén bedrijf is besmet en volgt een bestrijdingsplan. Met name het dagelijks terugkerende kalvermanagement vraagt de meeste aandacht.
    Besmettelijke dierziekten: geintegreerd aanpakken
    Hanekamp, W. ; Snoep, J. - \ 1998
    Praktijkonderzoek Rundvee, Schapen en Paarden. Praktijkonderzoek 11 (1998)4. - ISSN 1386-8470 - p. 25 - 29.
    diergeneeskunde - melkvee - melkveehouderij - infectieziekten - vaccinatie - immunisatie - immunotherapie - vaccins - preventieve geneeskunde - ziektepreventie - preventie - diergezondheid - hygiëne - ziekteoverdracht - dieren - zoönosen - veterinary science - dairy cattle - dairy farming - infectious diseases - vaccination - immunization - immunotherapy - vaccines - preventive medicine - disease prevention - prevention - animal health - hygiene - disease transmission - animals - zoonoses
    Omdat het dier de belangrijkste besmettingsbron is, is aankoop van vee een grote risicofactor en dienen mensen die veel in contact komen met dieren bedrijfskleding aan te trekken.
    Embryotransplantatie op de manier van KI. Niet-chirurgische methode is klaar voor testen in de praktijk.
    Hazeleger, W. ; Bouwman, E. ; Kemp, B. - \ 1998
    Boerderij/Varkenshouderij 83 (1998)7. - ISSN 0169-0167 - p. 30 - 31.
    diergeneeskunde - zeugen - zwangerschap - embryotransplantatie - eiceltransplantatie - kunstmatige inseminatie - vectorbestrijding - infectieziekten - veterinary science - sows - pregnancy - embryo transfer - ova transfer - artificial insemination - vector control - infectious diseases
    Uitleg van de methode van niet-chirurgische embryotransplantatie, die het mogelijk maakt om ziekte-insleep verder te minimaliseren
    Risk and economic consequences of contagious animal disease introduction
    Horst, H.S. - \ 1998
    Agricultural University. Promotor(en): A.A. Dijkhuizen; R.B.M. Huirne; P.W. de Leeuw. - Wageningen : WAU - ISBN 9789054857846 - 147
    diergeneeskunde - zoötechniek - virusziekten - infectieziekten - ziektepreventie - varkenspest - mond- en klauwzeer - ondernemingen - risico - besluitvorming - bedrijfsvoering - operationeel onderzoek - simulatie - werkschema - lineair programmeren - computersimulatie - simulatiemodellen - nederland - veterinary science - zootechny - viral diseases - infectious diseases - disease prevention - swine fever - foot and mouth disease - enterprises - risk - decision making - management - operations research - simulation - work flow - linear programming - computer simulation - simulation models - netherlands

    Introduction

    Within the European Union, epidemics of contagious animal diseases such as Classical Swine Fever (CSF) and Foot-and-Mouth Disease (FMD) are to be eradicated according to strict EU- prescriptions including stamping-out of infected herds, establishment of control and surveillance zones with complete standstill of animals and possible export bans on live animals. Epidemics clearly have a serious impact, in particular on countries with a high farm density and an export- oriented production, such as the Netherlands. Therefore, an effective animal disease prevention policy is of major importance for these countries.

    This thesis is a result of a joint action by the government and private industry in the Netherlands that have funded a research project aimed at gaining more insight into the risk and economic consequences of virus introduction into the country.

    Real-life experiments on strategies to reduce animal disease introduction and spread is not an option because such experiments would be too risky (and hence too costly). In principle, simulation modelling is an attractive alternative. It calculates the effects of predefined sets of input variables and therefore also offers the possibility of exploring strategies that have not been applied yet. Literature search showed that simulation models describing spread and economic consequences of epidemics within a country were already available. However, an integrated approach which combines the various aspects of outbreaks and spread with economic consequences of outbreaks was still lacking. Therefore, this research project emphasized the development of a model describing introduction of virus into the Netherlands and on the integration and combination of the models.

    Expert knowledge

    General

    As with every model, the quality of the outcome of a simulation model is strongly influenced by the quality of the input ('garbage in = garbage out'). Therefore, a considerable part of the research was devoted to the gathering of information on aspects influencing virus introduction. It would be ideal to base the simulation model on relevant historical and experimental data. However, such information on virus introduction is limited, if available at all. Furthermore, outbreaks of contagious animal diseases occur irregularly over time and differ in magnitude; moreover circumstances change. Therefore it is questionable if historical data are relevant in simulating current and future events. Experimental data are also sparsely available. Literature search has shown that many researchers have done work in the area of contagious animal diseases, but most of their findings are of a qualitative nature. Despite this lack of 'objective' information, decisions on eradication and prevention of outbreaks must be made. Currently, such decisions rely on the expertise (a combination of experience and understanding of current/future circumstances) of those working in this area. Such expertise is a useful and necessary addition to the data available from research and databases. The elicitation of this 'expert knowledge' in an objective way, resulting in quantitative information useful for modelling purposes, was one of the major topics in the thesis.

    Pilot experiment

    For the elicitation experiment a format was sought which would guarantee a high response from experts and would provide the ability to elicit individual opinions in an objective way. Literature search showed that many elicitation methods were available, all with their own pros and cons. One of the methods, Conjoint Analysis, was considered an interesting technique for the elicitation of the relative importance of the risk factors. Conjoint Analysis is well known in consumer and marketing studies, but thus far has not or only scarcely been used in the field of animal health economics. A pilot experiment was conducted in which the potential of the method for elicitation of the relative importance of risk factors was explored. In this experiment, the Conjoint Analysis technique was used to draw up a paper questionnaire which was handed out during the 7th International Symposium on Veterinary Epidemiology and Economics (ISVEE) held at Nairobi, Kenya, August 1994. Relevant ISVEE-participants asked to assign scores to profiles of six contagious animal diseases (African and Classical Swine Fever, Foot-and-Mouth Disease, Swine Vesicular Disease, Newcastle Disease, and Avian Influenza). The Kenya-experiment showed promising results. However, also some lessons for future use were learned. The 'paperapproach' resulted in a low response (30%) and the participants, who were not selected on the basis of their expertise, indicated that is was very difficult and time-consuming to evaluate six diseases at one time.

    Basic experiment: elicitation of opinion of Dutch experts

    The results and experiences of the Kenya experiment have led to and framed the use 0' Conjoint Analysis in a second and much bigger experiment during which the subjective knowledge of Dutch experts was elicited. Experts were defined as people that were involved in either research or policy-making on animal disease prevention and people that would be consulted in case of an outbreak. As the number of experts was limited, an approach was needed which would guarantee a high response rate. Therefore, the experiment was framed as a full evening's workshop. Such a workshop is a one-off group meeting, which means that the participants have to show up only once and have the possibility of discussing issues with other experts: both aspects may be attractive and incentives to join. This approach worked out well: the experiment was attended by a total of 43 out of 50 invited persons, a response rate of 86%.

    Although it was acknowledged that group discussions may have the advantage of resulting in new and better approaches because people are able to share, evaluate and stimulate each other's opinions, the risk of possible negative effects of such discussions, such as individual dominance, was too high. Therefore, the workshop participants were asked to individually complete a computerized questionnaire. The program was developed to be self-explanatory, which minimized the interaction among participants and between participants and facilitators. The participants were given the opportunity to indicate on which disease they felt themselves most knowledgeable and were only asked questions about that disease. Furthermore, in order to keep the whole exercise at a manageable size, the questions were confined to Europe, the countries being grouped into five clusters.

    Relative importance of risk factors

    The relative importance of risk factors responsible for the introduction of virus into the Netherlands was elicited by using the above-described Conjoint Analysis method. Questions were asked per country cluster. The results showed that, for both FMD and CSF major risk factors were import of livestock and returning trucks. Differences between country clusters were small. For NCD, major risk factors were import of live animals, transport materials (crates) and import of exotic birds.

    As a follow-up on the Kenya experiment, the Conjoint Analysis element of the workshop experiment was evaluated in detail on its usefulness as a tool to elicit expert knowledge in the field of animal health economics. Criteria were validity, consistency and respondent evaluation. The results obtained were comparable to or better than the results obtained in consumer and marketing studies. It was concluded that Conjoint Analysis provided a useful addition to the toolkit of the animal health economist.

    Frequency of outbreaks in Europe

    Each time an outbreak occurs in a European country, there is always a chance that the virus will be transferred to the Netherlands. A higher frequency of outbreaks in Europe means a higher risk of virus introduction to the Netherlands (and to all other countries). It was expected that estimates on the frequency of outbreaks would be difficult to make. Therefore, a method was chosen which enabled expression of uncertainty. This method, called ELI (elicitation), is a graphically-oriented computer program which facilitates the quantification of subjective knowledge about uncertain quantities. The program helps respondents produce subjective probability density functions (PDFs) and is based on socalled proper scoring rules. The top of a PDF indicates the best guess or most likely value, according to the respondent. The dispersion corresponds with the uncertainty as to this estimate.

    The ELI-element of the workshop resulted in the parameters of a normal distribution from all participants individually concerning the expected number of outbreaks within the next five years. The workshop participants expected numerous outbreaks of NCD and CSF but not so many of FMD. For all three diseases, most outbreaks were expected to occur in Eastern Europe (midpoints were 21, 20, and 21, for CSF FMD and NCD respectively). The smallest numbers were expected in the country cluster containing the UK, Ireland and Scandinavia (midpoints were 1, 0.5, and 2.5, for CSF, FMD and NCD respectively).

    High Risk Period

    The High Risk Period (HRP) defines the period in which the virus is already present in a country but not yet detected or under control. During this period, the virus may spread freely within the country and/or transferred to other countries. The HRP can be divided into two periods, the first one starting with infection of the first animal and ending when an infected animal is detected (HRP1), the second period starting with detection and ending when all measures are considered effective (i.e., no spread to other countries) (HRP2).

    The participating experts were asked to give a three-point estimate (minimum, most likely and maximum expected length) for the duration of both periods, for all country clusters and for the Netherlands. The HRP Is with the highest duration were expected for Eastern Europe (midpoints of 42, 19, and 21 days for CSF, FMD and NCD respectively). Shortest duration was expected for the cluster including the UK, Ireland and Scandinavia (midpoints were 21, 7, and 10 days for CSF, FMD and NCD respectively). Short durations were estimated for the Netherlands as well.

    The HRP2 estimates showed the same distribution over countries, but were longer for FMD and CSF and shorter for NCD.

    Risico-kwantificering en verzekering van veewetziekten
    Meuwissen, Miranda ; Horst, S. ; Huirne, R. ; Dijkhuizen, A. - \ 1997
    Praktijkonderzoek varkenshouderij 11 (1997)2. - ISSN 1382-0346 - p. 18 - 19.
    landbouw - diergezondheid - rundvee - ondernemingen - regering - overheidsbeleid - infectieziekten - marginale gebieden - varkens - risico - ondersteunende maatregelen - diergeneeskunde - veterinaire hygiëne - agriculture - animal health - cattle - enterprises - government - government policy - infectious diseases - less favoured areas - pigs - risk - support measures - veterinary science - veterinary hygiene
    Binnen Nederland hebben concentratiegebieden een grotere kans op een uitbraak van veewetziekten zoals Mond- en Klauwzeer (MKZ) en Klassieke Varkenspest (KVP) dan de niet-concentratiegebieden. Ook de schade als gevolg van een uitbraak is hoger voor de concentratiegebieden. De schade als gevolg van KVP kan variëren van 54 tot 490 miljoen gulden.
    Loonwerker helpt veehouder bij een betere bedrijfsgezondheid.
    Noordhuizen, J.P.T.M. ; Frankena, K. - \ 1997
    Landbouwmechanisatie 48 (1997)6/7. - ISSN 0023-7795 - p. 18 - 21.
    infectieziekten - ziektepreventie - diergeneeskunde - melkvee - melkveehouderij - dierlijke meststoffen - drijfmest - bacterieziekten - micro-organismen - virusziekten - diergezondheid - hygiëne - boerderij uitrusting - gezondheid op het werk - bedrijfshygiëne - loonbedrijven - infectious diseases - disease prevention - veterinary science - dairy cattle - dairy farming - animal manures - slurries - bacterial diseases - microorganisms - viral diseases - animal health - hygiene - farm equipment - occupational health - industrial hygiene - wage labour enterprises
    Net zoals een inseminator, een voorlichter, een dierenarts of willekeurig welke bezoeker is de loonwerker een mogelijke verspreider van smetstof. Hoe zit dat dan met smetstof en mest? Mest als een bron van mogelijke versleep van besmetting tussen bedrijven. Wat kun je er aan doen om die risico's te elimineren of op zijn minst te beperken? Dit artikel geeft u een aantal oplossingen
    Insleep en verspreiding van besmettelijke dierziekten. Beslissingsondersteuning met Monte Carlo simulatie.
    Horst, H.S. ; Jalvingh, A.W. ; Meuwissen, M.P.M. ; Nielen, M. ; Huirne, R.B.M. ; Dijkhuizen, A.A. - \ 1997
    Agro Informatica 10 (1997)2. - ISSN 0925-4455 - p. 26 - 28.
    diergeneeskunde - varkens - mond- en klauwzeer - varkenspest - infectieziekten - ziektepreventie - diergezondheid - hygiëne - computersimulatie - simulatie - simulatiemodellen - besluitvorming - bedrijfsvoering - operationeel onderzoek - werkschema - lineair programmeren - nederland - veterinary science - pigs - foot and mouth disease - swine fever - infectious diseases - disease prevention - animal health - hygiene - computer simulation - simulation - simulation models - decision making - management - operations research - work flow - linear programming - netherlands
    In deze bijdrage wordt een overzicht gegeven van het onderzoek met een simulatiemodel naar de kans van insleep van mond- en klauwzeer en varkenspest, en een overzicht van het onderzoek met een ander simulatiemodel naar de verspreiding van beide ziekten binnen Nederland
    Effect van moment van vlekziektevaccinatie op het interval spenen-bronst
    Riel, J. van; Vesseur, P. - \ 1996
    Praktijkonderzoek varkenshouderij 10 (1996)2. - ISSN 1382-0346 - p. 5 - 5.
    erysipelothrix - vruchtbaarheid - immunisatie - immunotherapie - infectieziekten - oestrus - biggen - zeugen - vaccinatie - vaccins - diergeneeskunde - spenen - erysipelothrix - fertility - immunization - immunotherapy - infectious diseases - oestrus - piglets - sows - vaccination - vaccines - veterinary science - weaning
    In de praktijk zijn er vragen over de gevolgen van vlekziektevaccinaties voor de vruchtbaarheid. Een oriënterende studie heeft aanwijzingen opgeleverd dat enten in de eerste week van de lactatie een negatieve invloed heeft op het interval spenen-bronst.
    Gezondheid van volierehennen op praktijkbedrijven
    Niekerk, Th.G.C.M. van; Bosch, J.G.M.J. - \ 1996
    Praktijkonderzoek voor de Pluimveehouderij 7 (1996)1. - ISSN 0924-9087 - p. 13 - 17.
    huisvesting, dieren - dierenwelzijn - escherichia coli - helminthosen - hennen - infecties - infectieziekten - mijten - nederland - diergeneeskunde - groepshuisvesting - animal housing - animal welfare - escherichia coli - helminthoses - hens - infections - infectious diseases - mites - netherlands - veterinary science - group housing
    Precies twee jaar geleden is een artikel gepubliceerd met de gezondheidsgegevens van 24 praktijkkoppels voliOrehennen (Periodiek 94/1). De gegevens werden verzameld in het kader van het Demo-project voor voliOrehuisvesting voor leghennen. Deze registratie is onverminderd doorgegaan en inmiddels zijn gegevens van 62 praktijkkoppels beschikbaar. Het werd daarom tijd om de stand nogmaals op te maken.
    Op zoek naar L. monocytogenes.
    Beumer, R.R. ; Giffel, M.C. te - \ 1996
    Voedingsmiddelentechnologie 29 (1996)21. - ISSN 0042-7934 - p. 45 - 48.
    analyse - chemie - voedselbesmetting - voedselmicrobiologie - infectieziekten - listeria - analytische scheikunde - analysis - chemistry - food contamination - food microbiology - infectious diseases - listeria - analytical chemistry
    Een uiteenzetting van de factoren die van invloed zijn op de isolatie, de bevstiging en de identificatie van genoemde pathogene bacterie
    Vrijwaringsprogramma''s tegen infectieziekten voor Nederlandse varkensbedrijven
    Swinkels, J.W.G.M. ; Vesseur, P.C. - \ 1995
    Rosmalen : Praktijkonderzoek varkenshouderij (Proefverslag / Praktijkonderzoek Varkenshouderij P1.128) - 36
    ziektebestrijding - infectieziekten - nederland - varkens - volksgezondheidsbevordering - diergeneeskunde - disease control - infectious diseases - netherlands - pigs - sanitation - veterinary science
    Op weg naar vrijwaring van infectieziekten!
    Swinkels, H. ; Vesseur, P. - \ 1995
    Praktijkonderzoek varkenshouderij 9 (1995)2. - ISSN 1382-0346 - p. 17 - 19.
    diergezondheid - samenwerking - ziektepreventie - hygiëne - infectieziekten - nederland - varkens - preventie - preventieve geneeskunde - diergeneeskunde - wetenschap - wetenschappelijke samenwerking - animal health - cooperation - disease prevention - hygiene - infectious diseases - netherlands - pigs - prevention - preventive medicine - veterinary science - science - scientific cooperation
    In een onderzoek van de gezamenlijke onderzoeksinstellingen zijn de in Nederland bekendste ziekteverwekkers gerangschikt op basis van bedreiging voor de sector en schade voor het varkensbedrijf. Na de verwekkers van veewetziekten en de Ziekte van Aujeszky stonden de verwekkers van salmonella, snuffelziekte, eenzijdige longontsteking, abortus blauw en hersenvlies- en gewrichtsontstekingen het hoogst genoteerd
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