Staff Publications

Staff Publications

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

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

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

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    Modelling of strategies for genetic control of scrapie in sheep : The importance of population structure
    Hagenaars, Thomas J. ; Melchior, Marielle B. ; Windig, Jack J. ; Bossers, Alex ; Davidse, Aart ; Zijderveld, Fred G. van - \ 2018
    PLoS ONE 13 (2018)3. - ISSN 1932-6203
    Scrapie is a transmissible spongiform encephalopathy in sheep and an example of a disease that may be controlled through breeding for disease resistance. Member states of the European Union have introduced strategies for breeding against scrapie based on the selection of genetically resistant breeding rams. An ambitious strategy adopted in The Netherlands consisted of selecting resistant rams for breeding throughout both breeding and production sectors. Mathematical modelling of the effect of a breeding program on the spreading capacity of scrapie in a national flock is needed for making assessments on how long a breeding strategy needs to be maintained to achieve disease control. Here we describe such a model applied to the Dutch situation, with the use of data on the genetic content of the Dutch sheep population as well as on scrapie occurrence in this population. We show that the time needed for obtaining scrapie control depends crucially on two parameters measuring sheep population structure: the between-flock heterogeneity in genotype frequencies, and the heterogeneity of mixing (contact rates) between sheep flocks. Estimating the first parameter from Dutch genetic survey data and assuming scenario values for the second one, enables model prediction of the time needed to achieve scrapie control in The Netherlands.
    Aanpassing en uitbreiding controlemethodiek BRT : aanbevelingen om de methodiek van externe kwalieteitscontrole voor de BasisRegistratie Topografie aan te passen en uit te breiden
    Storm, M.H. ; Davidse, J. ; Brus, D.J. - \ 2017
    Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2796) - 37
    Analysis of the possibilities for moving from 3 or 6 yearly snapshots into yearly partial incremental updates of land monitoring products, including the assessment of changes required in workflows. : Contract No 3436/B2015/RO-COPERNICUS/EEA.56195. European Environment Agency (EEA), Copenhagen, Denmark.
    Hazeu, G.W. ; Mücher, C.A. ; Davidse, J. ; Kosztra, B. ; Hayde, László ; Maucha, G. ; Soukup, T. - \ 2016
    Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie
    Langeveld, J.P.M. ; Jacobs, J.G. ; Erkens, J.H.F. ; Baron, T. ; Andreoletti, O. ; Yokoyama, T. ; Keulen, L.J.M. van; Zijderveld, F.G. van; Davidse, A. ; Hope, J. ; Tang, Y. ; Bossers, A. - \ 2014
    Prion 8 (2014)4. - ISSN 1933-6896 - p. 296 - 305.
    Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted
    in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions
    that BSE, classical scrapie and CH1641–a rare scrapie variant–could occur as mixtures. In field samples including those
    from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant
    part of the disease‑associated form of prion protein (PrPres) represents a powerful tool for quick discrimination
    purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrPres
    found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass
    of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie
    but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and
    CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a
    second PrPres population. The existence of these 2 PrPres populations was further confirmed through deglycosylation by
    PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain
    inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains
    should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other
    techniques suitable for strain typing.
    Viral diseases of wild and farmed European eel Anguilla anguilla with particular reference to the Netherlands
    Beurden, S.J. van; Engelsma, M.Y. ; Roozenburg, I. ; Voorbergen-Laarman, H.A. ; Tulden, P.W. van; Kerkhoff, S. ; Nieuwstadt, A. ; Davidse, A. ; Haenen, O.L.M. - \ 2012
    Diseases of Aquatic Organisms 101 (2012). - ISSN 0177-5103 - p. 69 - 86.
    pancreatic necrosis virus - pillar cell necrosis - herpesvirus-anguillae - japanese eel - japonica temminck - phylogenetic-relationships - rhabdoviral dermatitis - taxonomic position - genome sequence - rainbow-trout
    Diseases are an important cause of losses and decreased production rates in freshwater eel farming, and have been suggested to play a contributory role in the worldwide decline in wild freshwater eel stocks. Three commonly detected pathogenic viruses of European eel Anguilla anguilla are the aquabirnavirus eel virus European (EVE), the rhabdovirus eel virus European X (EVEX), and the alloherpesvirus anguillid herpesvirus 1 (AngHV1). In general, all 3 viruses cause a nonspecific haemorrhagic disease with increased mortality rates. This review provides an overview of the current knowledge on the aetiology, prevalence, clinical signs and gross pathology of these 3 viruses. Reported experimental infections showed the temperature dependency and potential pathogenicity of these viruses for eels and other fish species. In addition to the published literature, an overview of the isolation of pathogenic viruses from wild and farmed A. anguilla in the Netherlands during the past 2 decades is given. A total of 249 wild A. anguilla, 39 batches of glass eels intended for farming purposes, and 239 batches of farmed European eels were necropsied and examined virologically. AngHV1 was isolated from wild A. anguilla yellow and silver eels from the Netherlands from 1998 until the present, while EVEX was only found sporadically, and EVE was never isolated. In farmed A. anguilla AngHV1 was also the most commonly isolated virus, followed by EVE and EVEX.
    EU-Approved Rapid Tests for Bovine Spongform Encephalopathy Detect Atypical Forms: A Study for Their Sensitivities
    Meloni, D. ; Davidse, A. ; Langeveld, J.P.M. ; varello, K. ; Casalone, C. ; Corona, C. ; Balkema-Buschmann, A. ; Groschup, M. ; Ingravalle, F. ; Bozzetta, E. - \ 2012
    PLoS ONE 7 (2012)9. - ISSN 1932-6203 - 12 p.
    creutzfeldt-jakob-disease - bse-affected cattle - prion protein - scrapie - transmission - switzerland - primate - strain - prp
    Since 2004 it become clear that atypical bovine spongiform encephalopthies (BSEs) exist in cattle. Whenever their detection has relied on active surveillance plans implemented in Europe since 2001 by rapid tests, the overall and inter-laboratory performance of these diagnostic systems in the detection of the atypical strains has not been studied thoroughly to date. To fill this gap, the present study reports on the analytical sensitivity of the EU-approved rapid tests for atypical L-and H-type and classical BSE in parallel. Each test was challenged with two dilution series, one created from a positive pool of the three BSE forms according to the EURL standard method of homogenate preparation (50% w/v) and the other as per the test kit manufacturer's instructions. Multilevel logistic models and simple logistic models with the rapid test as the only covariate were fitted for each BSE form analyzed as directed by the test manufacturer's dilution protocol. The same schemes, but excluding the BSE type, were then applied to compare test performance under the manufacturer's versus the water protocol. The IDEXX HerdChek (R) BSE-scrapie short protocol test showed the highest sensitivity for all BSE forms. The IDEXX (R) HerdChek BSE-scrapie ultra short protocol, the Prionics (R) - Check WESTERN and the AJ Roboscreen (R) BetaPrion tests showed similar sensitivities, followed by the Roche (R) PrionScreen, the Bio-Rad (R) TeSeE (TM) SAP and the Prionics (R) - Check PrioSTRIP in descending order of analytical sensitivity. Despite these differences, the limit of detection of all seven rapid tests against the different classes of material set within a 2 log(10) range of the best-performing test, thus meeting the European Food Safety Authority requirement for BSE surveillance purposes. These findings indicate that not many atypical cases would have been missed surveillance since 2001 which is important for further epidemiological interpretations of the sporadic character of atypical forms.
    Four independent molecular prion protein parameters for discriminating new cases of C, L, and H BSE in cattle.
    Langeveld, J.P.M. ; Erkens, J.H.F. ; Rammel, I. ; Jacobs, J.G. ; Davidse, A. ; Zijderveld, F.G. van; Bossers, A. ; Schildorfer, H. - \ 2011
    Journal of Clinical Microbiology 49 (2011)8. - ISSN 0095-1137 - p. 3026 - 3028.
    monoclonal-antibodies - great-britain - atypical bse - identification - similarities - diseases - prpsc - rich
    In anticipation of the emergence of more variants of bovine spongiform encephalopathy (BSE), a semiquantitative display of the following four independent molecular diagnostic prion parameters was designed: N terminus, proteinase K (PK) resistance, glycoprofile, and mixed population. One H BSE case, three L BSE cases, six C BSE cases, and one unusual classical BSE (C BSE) case are reported.
    Active surveillance for scrapie in the Netherlands: effect of a breeding programme on the prevalence of scrapie in sheep (2002-2010)? = Acht jaar actieve scrapie-surveillance in Nederland: het effect van het fokprogramma op de prevalentie van schrapie bij het schaap (2002-2010)
    Melchior, M.B. ; Hagenaars, T.H.J. ; Davidse, A. ; Keulen, L.J.M. van; Bossers, A. ; Zijderveld, F.G. van - \ 2011
    Tijdschrift voor Diergeneeskunde 136 (2011)2. - ISSN 0040-7453 - p. 84 - 93.
    bovine spongiform encephalopathy - in-vitro conversion - natural scrapie - prion protein - immunohistochemical detection - experimental flock - bse - transmission - prp - susceptibility
    The susceptibility of sheep to scrapie is modulated by the prion protein (PrP) genotype of the animal. An ambitious voluntary scrapie control programme was started in the Netherlands in 1998, based on selection of rams with theARR/ARR genotype for breeding. This programme was followed by an obligatory programme in 2004; the programme has been voluntary since 2007. We monitored the prevalence of PrP genotype frequencies and the prevalence of scrapie in the Dutch sheep population between 2002 and June 2010. Results showed that selection for scrapie-resistant sheep resulted in an increase in the ARR allele frequency in the Dutch national flock from 37.5% in 2005 to 61.4% in 2009. Moreover, surveillance data showed that there was a significant decrease in the prevalence of scrapie a few years after the start of the obligatory breeding programme, from more than 0.2% in 2004 to 0.015% in 2009. This decrease is a consequence of the increased number of scrapie-resistant sheep in the Dutch sheep population. To date, the results and the models based on the data show that the selective breeding programme should be continued for several years in order to successfully eradicate scrapie. It will be important to monitor the PrP frequency and scrapie prevalence in the Dutch sheep population in the coming years.
    Eradication of scrapie with selective breeding: are we nearly there?
    Melchior, M.B. ; Windig, J.J. ; Hagenaars, T.H.J. ; Bossers, A. ; Davidse, A. ; Zijderveld, F.G. van - \ 2010
    BMC Veterinary Research 6 (2010). - ISSN 1746-6148 - 9 p.
    natural scrapie - transmission factors - great-britain - british sheep - cheviot sheep - closed flock - sip gene - prp gene - genotype - romanov
    Background: Following EU decision 2003/100/EC Member States have recently implemented sheep breeding programmes to reduce the prevalence of sheep with TSE susceptible prion genotypes. The present paper investigates the progress of the breeding programme in the Netherlands. The PrP genotype frequencies were monitored through time using two sets of random samples: one set covers the years 2005 to 2008 and is taken from national surveillance programme; the other is taken from 168 random sheep farms in 2007. The data reveal that although the level of compliance to the breeding programme has been high, the frequency of susceptible genotypes varies substantially between farms. The 168 sheep farms are a subset of 689 farms participating in a postal survey inquiring about management and breeding strategies. This survey aimed to identify how much these strategies varied between farms, in order to inform assessment of the expected future progress towards eradication of classical scrapie. Results: On the one hand, we found that compliance to the national breeding program has been high, and the frequency of resistant genotypes is expected to increase further in the next few years. On the other hand, we observed a large variation in prevalence of the scrapie resistant PrP genotype ARR between farms, implicating a large variation of genetic resistance between farms. Substantial between-flock differences in management and breeding strategies were found in the postal survey, suggesting considerable variation in risk of scrapie transmission between farms. Conclusions: Our results show that although there has been a good progress in the breeding for scrapie resistance and the average farm-level scrapie susceptibility in the Netherlands has been significantly reduced, still a considerable proportion of farms contain high frequencies of susceptible genotypes in their sheep population. Since 2007 the breeding for genetic resistance is voluntarily again, and participation to selective breeding can decrease as a result of this. This, together with the patterns of direct and indirect contact between sheep farms, might present a challenge of the aim of scrapie eradication. Communication to sheep owners of the effect of the breeding programme thus far, and of the prospects for classical scrapie eradication in The Netherlands might be essential for obtaining useful levels of participation to the voluntary continuation of the breeding programme.
    Multi-Dynamics and time aspects in Spatial Planning
    Knaap, W.G.M. van der; Davidse, B.J. - \ 2010
    Multi-Dynamics and Time aspects in Spatial Planning
    Knaap, W.G.M. van der; Davidse, B.J. - \ 2010
    In: Deltas in Depth, Deltas in Times of Climate Change, Rotterdam, The Netherlands, 29 September - 1 October 2010. - Rotterdam : Programme Office Knowledge for Climate - p. 79 - 79.
    While time goes by: dealing with Time and Multi-Dynamics in Spatial Planning and Design
    Knaap, W.G.M. van der; Davidse, B.J. - \ 2010
    In: Book of abstracts of the 24th AESOP Annual Conference on Space is Luxury, Aalto, Finland, 7-10 July 2010. - Helsinki : Association of European Schools of Planning - p. 438 - 439.
    Scrapie prevalence in sheep of susceptible genotype is declining in a population subject to breeding for resistance
    Hagenaars, T.H.J. ; Melchior, M.B. ; Bossers, A. ; Davidse, A. ; Engel, B. ; Zijderveld, F.G. van - \ 2010
    BMC Veterinary Research 6 (2010). - ISSN 1746-6148
    great-britain - british sheep - classical scrapie - active surveillance - prp genotype - flock - program - risk - bse - epidemiology
    Background - Susceptibility of sheep to scrapie infection is known to be modulated by the PrP genotype of the animal. In the Netherlands an ambitious scrapie control programme was started in 1998, based on genetic selection of animals for breeding. From 2002 onwards EU regulations required intensive active scrapie surveillance as well as certain control measures in affected flocks. Here we analyze the data on genotype frequencies and scrapie prevalence in the Dutch sheep population obtained from both surveillance and affected flocks, to identify temporal trends. We also estimate the genotype-specific relative risks to become a detected scrapie case. Results - We find that the breeding programme has produced a steady increase in the level of genetic scrapie resistance in the Dutch sheep population. We also find that a significant decline in the prevalence of scrapie in tested animals has occurred a number of years after the start of the breeding programme. Most importantly, the estimated scrapie prevalence level per head of susceptible genotype is also declining significantly, indicating that selective breeding causes a population effect. Conclusions - The Dutch scrapie control programme has produced a steady rise in genetic resistance levels in recent years. A recent decline in the scrapie prevalence per tested sheep of susceptible prion protein genotype indicates that selective breeding causes the desired population effect.
    Impact of eel viruses on recruitment of European eel
    Haenen, O.L.M. ; Ginneken, V.J.T. van; Engelsma, M.Y. ; Thillart, G.E.E.J.M. - \ 2009
    In: Spawning and Migration of the European Eel / J.C. Rankin G. van den Thillart, S. Dufour, Springer Netherlands (Fish and Fisheries Series 30) - ISBN 9781402090943 - p. 387 - 400.
    Eels have an uncommon catadromic life cycle with exceptional migratory patterns to their spawning grounds several thousand kilometres away: the European eel (Anguilla anguilla) travels over 5,500 km to the Sargasso Sea (Schmidt 1923; McCleave and Kleckner 1987; Tesch 1982; Tesch and Wegner 1990); the American eel (A. rostrata) migrates over 4,000 km also to the Sargasso Sea (Castonguay and McCleave 1987; McCleave and Kleckner 1987; Tesch and Wegner 1990); the Australian eel (A. aus-tralis) travels over 5,000 km into the Pacific Ocean to spawn (Jellyman 1987); and the Japanese eel (A. japonica) travels over 4,000 km to an area near the Marianna Islands in the Philippines to spawn (Tsukamoto 1992). Evidently such long distance swimming will place those fishes under extra stress caused by the long starvation period, the high energy cost of the journey, and the many changes in the environment such as salt water, darkness, high pressure, and low temperatures, among other stress factors. Stress is often a basis for disease in eel, especially in intensive eel culture (Haenen and Engelsma, 2005 unpublished finding). Nowadays, global transport of live fishes for aquaculture has facilitated the global spread of pathogens from diseased to healthy stocks. Within the last few decades, aquaculture has become an important production branch in our society. Its global production has more than doubled between 1986 and 1996 in tonnage and value, and over one quarter of human fish consumption at world scale is now produced in aquaculture (Naylor et al. 2000). The Netherlands is one of the leading eel producing & trading countries (Heinsbroek and Kamstra 1995). Blanc (1997) showed that nearly 100 pathogens have been introduced into European water bodies since the introduction of aquaculture. Worldwide many diseases are known in both wild and cultured eel. Parasites, for example trematodes, Anguillicola crassus(nematode), and Myxidium giardi (myxosporean)occur naturally in wild eel populations, mostly in low numbers, without causing mortality (Køie 1988; Van Banning and Haenen 1990; Borgsteede et al. 1999). However, under culture conditions, with eels kept in high densities, they may be harmful. Eel pathogenic bacteria like Vibrio vulnificus, Vibrio anguillarum, Pseudomonas anguillisepticaand Edwardsiella tardamay also cause disease, especially when a stress factor is involved or when the eel is injured (Veenstra et al. 1993; Austin and Austin 1999; Haenen and Davidse 2001). As far as we know, the clinical signs are often more severe under culture conditions compared to in the wild.
    Discrimination of 3 molecular types of protease resistant prion protein in brain diagnosed with bovine spongiform encephalopathy
    Jacobs, J.G. ; Langeveld, J.P.M. ; Biacabe, A.G. ; Acutis, P.L. ; Mazza, M. ; Polak, M.P. ; Gavier-Widen, D. ; Buschmann, A. ; Groschup, M.H. ; Zijderveld, F.G. van; Davidse, A. ; Baron, T. - \ 2008
    BSE in The Netherlands: 15 years of surveillance
    Zijderveld, F.G. van; Heres, L. ; Davidse, A. ; Bossers, A. ; Langeveld, J.P.M. ; Keulen, L.J.M. van - \ 2008
    TSE surveillance in sheep in The Netherlands
    Zijderveld, F.G. van; Heres, L. ; Davidse, A. ; Bossers, A. ; Langeveld, J.P.M. ; Keulen, L.J.M. van - \ 2008
    Small ruminants with transmissible spongiform encephalopathies analyzed for properties of PrpSc and PrPres
    Langeveld, J.P.M. ; Erkens, J.H.F. ; Benestad, S.L. ; Jacobs, J.G. ; Keulen, L.J.M. van; Davidse, A. ; Bossers, A. ; Zijderveld, F.G. van - \ 2007
    Molecular discrimination of atypical bovine spongiform encephalopathy strains from a geographical region spanning a wide area in Europe
    Jacobs, J.G. ; Langeveld, J.P.M. ; Biacabe, A.G. ; Acutis, P.L. ; Polak, M.P. ; Gavier-Widen, D. ; Buschmann, A. ; Caramelli, M. ; Casalone, C. ; Mazza, M. ; Groschup, M. ; Erkens, J.H.F. ; Davidse, A. ; Zijderveld, F.G. van; Baron, T. - \ 2007
    Journal of Clinical Microbiology 45 (2007)6. - ISSN 0095-1137 - p. 1821 - 1829.
    transmissible mink encephalopathy - creutzfeldt-jakob-disease - abnormal prion protein - transgenic mice - monoclonal-antibodies - messenger-rna - scrapie agent - n-glycosidase - brain-stem - prp gene
    Transmissible spongiform encephalopathy strains can be differentiated by their behavior in bioassays and by molecular analyses of the disease-associated prion protein (PrP) in a posttranslationally transformed conformation (PrPSc). Until recently, isolates from cases of bovine spongiform encephalopathy (BSE) appeared to be very homogeneous. However, a limited number of atypical BSE isolates have recently been identified upon analyses of the disease-associated proteinase K (PK) resistance-associated moiety of PrPSc (Prp(res)), suggesting the existence of at least two additional BSE PrPres variants. These are defined here as the H type and the L type, according to the higher and lower positions of the nonglycosylated PrPres band in Western blots, respectively, compared to the position of the band in classical BSE (C-type) isolates. These molecular Prpres variants, which originated from six different European countries, were investigated together. In addition to the migration properties and glycosylation profiles (glycoprofiles), the H- and L-type isolates exhibited enhanced PK sensitivities at pH 8 compared to those of the C-type isolates. Moreover, H-type BSE isolates exhibited differences in the binding of antibodies specific for N- and more C-terminal PrP regions and principally contained two aglycosylated PrPres moieties which can both be glycosylated and which is thus indicative of the existence of two PrPres, populations or intermediate cleavage sites. These properties appear to be consistent within each BSE type and independent of the geographical origin, suggesting the existence of different BSE strains in cattle. The choice of three antibodies and the application of two pHs during the digestion of brain homogenates provide practical and diverse tools for the discriminative detection of these three molecular BSE types and might assist with the recognition of other variants.
    Herpesvirus anguillae (HVA) isolations from disease outbreaks in cultured European eel, Anguilla anguilla in the Netherlands since 1996
    Haenen, O.L.M. ; Dijkstra, S.G. ; Tulden, P.W. van; Davidse, A. ; Nieuwstadt, A.P. van; Wagenaar, F. ; Wellenberg, G.J. - \ 2002
    Bulletin of the European Association of Fish Pathologists 22 (2002)4. - ISSN 0108-0288 - p. 247 - 257.
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