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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Genetic management without pedigree: effectiveness of a breeding circle in a rare sheep breed
Windig, Jack ; Priem, J. ; Bossers, A. ; Langeveld, J.P.M. ; Hoving, A.H. - \ 2017
EU-approved rapid tests might underestimate bovine spongiform encephalopathy infection in goats
Meloni, Daniela ; Bozzetta, Elena ; Langeveld, Jan P.M. ; Groschup, Martin H. ; Goldmann, Wilfred ; Andrèoletti, Olivier ; Lantier, Isabelle ; Keulen, Lucien Van; Bossers, Alex ; Pitardi, Danilo ; Nonno, Romolo ; Sklaviadis, Theodoros ; Ingravalle, Francesco ; Peletto, Simone ; Colussi, Silvia ; Acutis, Pier Luigi - \ 2017
Journal of Veterinary Diagnostic Investigation 29 (2017)2. - ISSN 1040-6387 - p. 232 - 236.
Bovine spongiform encephalopathy - diagnosis - EU - goats - rapid tests - scrapie - sensitivity - surveillance
We report the diagnostic sensitivity of 3 EU-approved rapid tests (ELISAs; 1 from IDEXX and 2 from Bio-Rad) for the detection of transmissible spongiform encephalopathy diseases in goats. Ninety-eight goat brainstem samples were tested. All the rapid tests had 100% specificity and ≥80% sensitivity, with the IDEXX test significantly more sensitive than the 2 Bio-Rad tests. All tests detected 100% of samples from goats with clinical scrapie, but missed 8% (IDEXX) to 33% (Bio-Rad SG) of samples from preclinical goats. Importantly, only IDEXX picked up all samples from clinical bovine spongiform encephalopathy (BSE)-infected goats, whereas the other 2 rapid tests missed 15% (Bio-Rad SG) to 25% (Bio-Rad SAP). These results show that a fraction of preclinical scrapie infections are likely missed by EU surveillance, with sensitivity of detection strongly dependent on the choice of the rapid test. Moreover, a significant proportion of clinical BSE infections are underestimated by using either Bio-Rad test. Assuming that the same sensitivity on preclinical goats would also occur in BSE-infected goats, our data suggest that IDEXX is likely the most sensitive test for detecting preclinical field cases of BSE infection in goats, although with an 8% failure rate. These results raise some concerns about the reliability of current EU surveillance figures on BSE infection in goats.
The relationship between taste and nutrient content in commercially available foods from the United States
Langeveld, A.W.B. van; Gibbons, Shannon ; Koelliker, Yvonne ; Civille, Gail V. ; Vries, J.H.M. de; Graaf, C. de; Mars, M. - \ 2017
Food Quality and Preference 57 (2017). - ISSN 0950-3293 - p. 1 - 7.
Taste is often suggested to have a nutrient-signalling function that may be important for food intake regulation, though limited data exists to support this notion. This study aimed to investigate the relationship between taste and nutrient content, and to explore the effect of food form on this relationship (liquid, semi-solid or solid), in a range of commercially available foods from the United States. Basic taste intensities (sweetness, saltiness, sourness and bitterness) of 237 processed foods were obtained by an expert sensory panel using the Spectrum™ method. Sweet taste intensity was associated with mono- and disaccharides (r = 0.70, p < 0.001), but not energy content (r = 0.11, p > 0.05). Salt taste intensity was associated with sodium (r = 0.72, p < 0.001) and protein (r = 0.39, p < 0.001), and fat (r = 0.37, p < 0.001) and energy content (r = 0.43, p < 0.001). Contrary to expectations, associations between taste and nutrient content were not stronger in liquids than in (semi-)solids. Cluster analysis on taste revealed 3 food groups: a sweet, salty and neutral tasting food group. Saltiness was associated with sodium content in salty foods (r = 0.39, p < 0.001) but not in sweet foods (r = 0.30, p > 0.05). Sweetness was associated with mono- and disaccharides in sweet foods (r = 0.55, p < 0.001) and in salty foods (r = 0.33, p < 0.001). In conclusion, our findings suggest that sweet and salt taste intensity can signal the presence of nutrients, in particular mono- and disaccharides and sodium. However, the relationship between taste and nutrients may be weaker in complex foods with competing tastes. The effect of food form on this relationship is more difficult to demonstrate in real-life foods.
Genetic, histochemical and biochemical studies on goat TSE cases from Cyprus
Niedermeyer, Susanne ; Eiden, Martin ; Toumazos, Pavlos ; Langeveld, Jan ; Bossers, Alex - \ 2016
Veterinary Research 47 (2016). - ISSN 0928-4249 - 14 p.

Scrapie and bovine spongiform encephalopathy (BSE) are transmissible spongiform encephalopathies (TSE's) affecting sheep and goats. Susceptibility of goats to scrapie is influenced by polymorphisms of the prion protein gene (PRNP) of the host. Five polymorphisms are associated with reduced susceptibility to TSE's. In the study presented here caprine samples from a scrapie eradication program on Cyprus were genotyped and further characterized using BioRad TeSeE rapid test, histological, immunohistochemical and biochemical methods. In total 42 goats from 20 flocks were necropsied from which 25 goats showed a positive result in the rapid test, a spongiform encephalopathy and an accumulation of pathological prion protein (PrPSc) in the obex. PrPSc deposits were demonstrated in the placenta, peripheral nervous and lymphoreticular system. Two animals showed PrPSc-accumulations in peripheral tissues only. By discriminatory immunoblots a scrapie infection could be confirmed for all cases. Nevertheless, slight deviations in the glycosylation pattern might indicate the presence of different scrapie strains. Furthermore scrapie samples from goats in the current study demonstrated less long term resistance to proteinase K than ovine or caprine BSE control samples. Reduced scrapie susceptibility according to the PRNP genotype was demonstrated (Fishers Exact test, p <0.05) for the goats with at least one polymorphism (p = 0.023) at the six codons examined and in particular for those with polymorphisms at codon 146 (p = 0.016). This work characterizes scrapie in goats having implications for breeding and surveillance strategies.

Scrapie incidence and PRNP polymorphisms : Rare small ruminant breeds of Sicily with TSE protecting genetic reservoirs
Vitale, Maria ; Migliore, Sergio ; Giglia, Maria La; Alberti, Placido ; Marco Lo Presti, Vincenzo Di; Langeveld, Jan P.M. - \ 2016
BMC Veterinary Research 12 (2016)1. - ISSN 1746-6148
Autochthonous breeds - Breeding programs - PRNP polymorphism - Scrapie surveillance - TSE

Background: Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative diseases of several mammalian species, including humans. In Italy, the active surveillance through rapid tests on brain stem from small ruminants started in 2002 on randomly selected samples of healthy slaughtered animals. Sampling number was proportionally related to the regional small ruminant population. Of the twenty Italian regions, Sicily has the second largest population of small ruminants which is mainly constituted by crossbreed animals (>70 %). Sicily contains also three native sheep breeds Pinzirita, Comisana and Valle del Belice. Native goat breeds are Girgentana, Messinese, Argentata dell'Etna, Maltese and Rossa Mediterranea. The polymorphisms of prion protein gene (PRNP) may influence disease susceptibility and breeding programs for genetic TSE resistance are being applied in sheep. Protective alleles have been recently reported for goats also. These differ from those in sheep and may allow breeding programs in the near future. In this paper the data of active surveillance for scrapie control in general population of small ruminants in Sicily are reported together with the analysis on the polymorphism of PRNP in a number of Sicilian autochthonous breeds. The evaluation of the frequency of protective alleles is fundamental for the implementation of a TSE resistance breeding program. Results: TSE surveillance in small ruminants in Sicily showed a of total fifty seven scrapie outbreaks from 1997 to 2014 involving mainly crossbreed animals. The PRNP polymorphism analysis in autochthonous breeds showed protective allele frequencies of 30-40 % ARR in sheep and 12-18 % K222 in three of the four goat breeds; these breeds are distributed over limited areas of the island. Conclusion: The study on PRNP polymorphisms in Sicilian small ruminant population showed higher frequency of the protective alleles compared to most other European breeds. Our results suggest that PRNP genetic variety in Sicilian sheep and goats can be a resource for TSE resistance breeding programmes while maintaining the conservation of endangered breeds and valorisation of their typical food products.

Variation in the prion protein sequence in Dutch goat breeds
Windig, J.J. ; Hoving, R.A.H. ; Priem, J. ; Bossers, A. ; Keulen, L.J.M. van; Langeveld, J.P.M. - \ 2016
Journal of Animal Breeding and Genetics 133 (2016)5. - ISSN 0931-2668 - p. 366 - 374.
Goat - Haplotype frequency - Scrapie

Scrapie is a neurodegenerative disease occurring in goats and sheep. Several haplotypes of the prion protein increase resistance to scrapie infection and may be used in selective breeding to help eradicate scrapie. In this study, frequencies of the allelic variants of the PrP gene are determined for six goat breeds in the Netherlands. Overall frequencies in Dutch goats were determined from 768 brain tissue samples in 2005, 766 in 2008 and 300 in 2012, derived from random sampling for the national scrapie surveillance without knowledge of the breed. Breed specific frequencies were determined in the winter 2013/2014 by sampling 300 breeding animals from the main breeders of the different breeds. Detailed analysis of the scrapie-resistant K222 haplotype was carried out in 2014 for 220 Dutch Toggenburger goats and in 2015 for 942 goats from the Saanen derived White Goat breed. Nine haplotypes were identified in the Dutch breeds. Frequencies for non-wild type haplotypes were generally low. Exception was the K222 haplotype in the Dutch Toggenburger (29%) and the S146 haplotype in the Nubian and Boer breeds (respectively 7 and 31%). The frequency of the K222 haplotype in the Toggenburger was higher than for any other breed reported in literature, while for the White Goat breed it was with 3.1% similar to frequencies of other Saanen or Saanen derived breeds. Further evidence was found for the existence of two M142 haplotypes, M142/S240 and M142/P240. Breeds vary in haplotype frequencies but frequencies of resistant genotypes are generally low and consequently selective breeding for scrapie resistance can only be slow but will benefit from animals identified in this study. The unexpectedly high frequency of the K222 haplotype in the Dutch Toggenburger underlines the need for conservation of rare breeds in order to conserve genetic diversity rare or absent in other breeds.

Prion type-dependent deposition of PRNP allelic products in heterozygous sheep
Langeveld, J.P.M. ; Jacobs, J.G. ; Hunter, N. ; Keulen, L.J.M. van; Lantier, F. ; Zijderveld, F.G. van; Bossers, A. - \ 2016
Journal of Virology 90 (2016)2. - ISSN 0022-538X - p. 805 - 812.

Susceptibility or resistance to prion infection in humans and animals depends on single prion protein (PrP) amino acid substitutions in the host, but the agent's modulating role has not been well investigated. Compared to disease incubation times in wild-type homozygous ARQ/ARQ (where each triplet represents the amino acids at codons 136, 154, and 171, respectively) sheep, scrapie susceptibility is reduced to near resistance in ARR/ARR animals while it is strongly enhanced in VRQ/VRQ carriers. Heterozygous ARR/VRQ animals exhibit delayed incubation periods. In bovine spongiform encephalopathy (BSE) infection, the polymorphism effect is quite different although the ARR allotype remains the least susceptible. In this study, PrP allotype composition in protease-resistant prion protein (PrPres) from brain of heterozygous ARR/ VRQ scrapie-infected sheep was compared with that of BSE-infected sheep with a similar genotype. A triplex Western blotting technique was used to estimate the two allotype PrP fractions in PrPres material from BSE-infected ARR/VRQ sheep. PrPres in BSE contained equimolar amounts of VRQ- and ARR-PrP, which contrasts with the excess (>95%) VRQPrP fraction found in PrP in scrapie. This is evidence that transmissible spongiform encephalopathy (TSE) agent properties alone, perhaps structural aspects of prions (such as PrP amino acid sequence variants and PrP conformational state), determine the polymorphic dependence of the PrPres accumulation process in prion formation as well as the disease-associated phenotypic expressions in the host.

Immunolabelling of non-phosphorylated neurofilament indicates damage of spinal cord axons in TSE-infected goats
Nadeem, M. ; Spitzbarth, I. ; Haist, V. ; Rohn, K. ; Tauscher, K. ; Rohn, K. ; Bossers, A. ; Langeveld, J. ; Papasavva-Stylianou, P. ; Groschup, M.H. ; Baumgärtner, W. ; Gerhauser, I. ; Fast, C. - \ 2016
Veterinary Record 178 (2016)6. - ISSN 0042-4900 - p. 141 - 141.
Prion protein genotype survey confirms low frequency of scrapie-resistant K222 allele in British goat herds
Goldmann, W. ; Stewart, P. ; Marier, E. ; Konold, T. ; Street, S. ; Windl, O. ; Ortiz-Pelaez, A. ; Langeveld, J. - \ 2016
Veterinary Record 178 (2016)7. - ISSN 0042-4900 - p. 168 - 168.

Scrapie in goats is a transmissible, fatal prion disease, which is endemic in the British goat population. The recent success in defining caprine PRNP gene variants that provide resistance to experimental and natural classical scrapie has prompted the authors to conduct a survey of PRNP genotypes in 10 goat breeds and 52 herds to find goats with the resistant K222 allele. They report here the frequencies in 1236 tested animals of the resistance-associated K222 and several other alleles by breed and herd. Eight animals were found to be heterozygous QK222 goats (0.64 per cent genotype frequency, 95 per cent CI 0.28 to 1.27 per cent) but no homozygous KK222 goats were detected. The K222 allele was found in Saanen, Toggenburg and Anglo-Nubian goats. The fact that only a few goats with the K222 allele have been identified does not preclude the possibility to design and implement successful breeding programmes at national level.

Cost-effective and integrated optimization of the Eindhoven urban wastewater system: From modelling to implementation
Benedetti, Lorenzo ; Langeveld, Jeroen ; Amerlinck, Youri ; Jonge, Jarno de; Klein, Jeroen de; Flameling, Tony ; Nopens, Ingmar ; Zanten, Oscar van; Weijers, Stefan - \ 2015
In: 88th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2015. - Water Environment Federation - ISBN 9781510870468 - p. 344 - 347.
Cost-effective systems upgrade - Impact based real-time control - Integrated urban wastewater system modelling - Optimization

This project aims at finding cost-efficient adaptive measures to meet the EU Water Framework Directive goals for the Dommel River (The Netherlands). Both acute and long-term impacts of the urban wastewater system (treatment plant and sewers) on the chemical and ecological quality of the river are studied. An integrated model, which proved to be a powerful tool to analyse the interactions within the integrated urban wastewater system, was used to evaluate several different measures in the urban wastewater system both using the existing as well as new infrastructure and real-time control (RTC) strategies. In this paper, emphasis is put on the results from the latest integrated RTC design and model-based evaluation, and on the first tests on the real system of selected measures, i.e. modified primary treatment, and improved rain buffer tank control and in-stream aeration.

Fokken en scrapie resistentie in Nederlandse geiten
Windig, J.J. ; Hoving, A.H. ; Priem, J. ; Keulen, L. van; Langeveld, J. - \ 2015
Behoud TSE-ongevoelige geiten (TSE=overdraagbare sponsvormige hersenaandoening zoals scrapie, atypische scrapie, of BSE)
Windig, J.J. ; Langeveld, J.P.M. ; Keulen, L.J.M. van; Hoving, A.H. - \ 2015
Zeldzaam huisdier 2015 (2015). - ISSN 0929-905X
Effect of Q211 and K222 PRNP polymorphic variants in the susceptibility of goats to oral infections with Goat Bovine Spongiform Encephalopathy
Aguilar-Calvo, Patricia ; Fast, C. ; Tauscher, Kerstin ; Espinosa, J.C. ; Groschup, M.H. ; Muhammad, Nadeem ; Goldmann, W. ; Langeveld, J.P.M. ; Bossers, A. ; Andreoletti, O. - \ 2015
The Journal of Infectious Diseases 212 (2015)4. - ISSN 0022-1899 - p. 664 - 672.
Background. The prion protein-encoding gene (PRNP) is one of the major determinants for scrapie occurrence in sheep and goats. However, its effect on bovine spongiform encephalopathy (BSE) transmission to goats is not clear.

Methods. Goats harboring wild-type, R/Q211 or Q/K222 PRNP genotypes were orally inoculated with a goat-BSE isolate to assess their relative susceptibility to BSE infection. Goats were killed at different time points during the incubation period and after the onset of clinical signs, and their brains as well as several peripheral tissues were analyzed for the accumulation of pathological prion protein (PrPSc) and prion infectivity by mouse bioassay.

Results. R/Q211 goats displayed delayed clinical signs compared with wild-type goats. Deposits of PrPSc were detected only in brain, whereas infectivity was present in peripheral tissues too. In contrast, none of the Q/K222 goats showed any evidence of clinical prion disease. No PrPSc accumulation was observed in their brains or peripheral tissues, but very low infectivity was detected in some tissues very long after inoculation (44–45 months).

Conclusions. These results demonstrate that transmission of goat BSE is genotype dependent, and they highlight the pivotal protective effect of the K222 PRNP variant in the oral susceptibility of goats to BSE.
Goat scrapie resistance: Monitoring, genotyping and breeding
Hoving, A.H. ; Windig, J.J. ; Langeveld, J.P.M. ; Keulen, L.J.M. van; Priem, J. ; Bossers, A. - \ 2015
Climate Change in Southern Africa: Farmers’ Perceptions and Responses
Kuivanen, K. ; Alvarez, S. ; Langeveld, C.A. - \ 2015
Wageningen UR - 46 p.
climatic change - farmers - attitudes - knowledge systems - adaptation - rural communities - southern africa - klimaatverandering - boeren - kennissystemen - adaptatie - plattelandsgemeenschappen - zuidelijk afrika
Southern Africa is characterized by natural climate variability onto which human-induced climate change is being superimposed. Rural communities that depend heavily on rain-fed agriculture for their livelihood are particularly vulnerable to the effects of climate-related change. This report takes stock of existing perceptions of- and responses to climate change among smallholder farmers in the region, in the hope of contributing to a better understanding of the complexities of local knowledge- and adaptation systems.
Vaak scrapieresistentie bij Nederlandse Toggenburgers
Hoving-Bolink, A.H. ; Windig, J.J. ; Koekoek, A. ; Hoekstra, H. ; Oldenbroek, J.K. ; Langeveld, J. - \ 2015
Zeldzaam huisdier 40 (2015)1. - ISSN 0929-905X - p. 20 - 21.
rassen (dieren) - geitenrassen - zeldzame rassen - genetische variatie - scrapie - ziekteresistentie - nederlandse toggenburgergeit - geitenziekten - dierveredeling - toegepast onderzoek - breeds - goat breeds - rare breeds - genetic variation - disease resistance - dutch toggenburg - goat diseases - animal breeding - applied research
Zeldzame Nederlandse rassen zijn niet alleen onderdeel van ons cultureel erfgoed, maar hebben soms ook een verrassende genetische variant. Zo is sinds een paar jaar bekend dat er een allel bestaat dat bescherming biedt tegen scrapie. In onderzoek van Wageningen UR met de geitensector blijkt dat het relatief kleine ras de Nederlandse Toggenburger veel dieren kent met het scrapieresistentie allel.
TSE strain differentiation in mice by immunohistochemical PrPSc profiles and triplex Western blot
Keulen, L.J.M. van; Langeveld, J.P.M. ; Dolstra, C.H. ; Jacobs, J.G. ; Bossers, A. ; Zijderveld, F.G. van - \ 2015
Neuropathology and Applied Neurobiology 41 (2015)6. - ISSN 1365-2990 - p. 756 - 779.
TSE strains are routinely identified by their incubation period and vacuolation profile in the brain after intracerebral inoculation and serial passaging in inbred mouse lines. There are some major drawbacks to this method that are related to the variation in vacuolation that exists in the brains of mice infected with the same TSE strain and to variation between observers and laboratories in scoring vacuolation and determining the final incubation period. Aim: We investigated the potential of PrPSc immunohistochemistry and triplex Western blotting as possible alternative methods to differentiate between TSE strains. Methods: TSE reference strains ME7, 87A/87V, 22A/22C, 79A/79V and 301C/301V were intracerebrally inoculated in RIII or VM inbred mice that differ in their PrP genotype. Immunohistochemical PrPSc profiles were drawn up by scanning light microscopy both on coronal and sagittal sections. Results: On the basis of the localization of PrPSc in the cerebral cortex, hippocampus, and cerebellar cortex and the overall type of PrPSc staining, all TSE strains could be well differentiated from each other through their typical strain dependent characteristics. In addition, Western blot showed that the combination of glycosylation profile and 12B2 epitope content of PrPSc allowed to distinguish between all reference strains except for ME7 and 22A in VM mice. Conclusion: TSE strains in mice can be identified on the basis of their PrPSc profile alone. The potential to identify TSE strains in ruminants with these PrPSc profiles after a single primary passage in mice will be the topic of future studies.
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.
Analyzing the effect of biofuel expansion on land use in major producing countries: evidence of increased multiple cropping
Langeveld, J.W.A. ; Dixon, J. ; Keulen, H. van; Quist-Wessel, P.M.F. - \ 2014
Biofuels Bioproducts and Biorefining 8 (2014)1. - ISSN 1932-104X - p. 49 - 58.
Estimates on impacts of biofuel production often use models with limited ability to incorporate changes in land use, notably cropping intensity. This review studies biofuel expansion between 2000 and 2010 in Brazil, the USA, Indonesia, Malaysia, China, Mozambique, South Africa plus 27 EU member states. In 2010, these countries produced 86 billion litres of ethanol and 15 billion litres of biodiesel. Land use increased by 25 Mha, of which 11 Mha is associated with co-products, i.e. by-products of biofuel production processes used as animal feed. In the decade up to 2010, agricultural land decreased by 9 Mha overall. It expanded by 22 Mha in Brazil, Indonesia, Malaysia, and Mozambique, some 31 Mha was lost in the USA, the EU, and South Africa due to urbanization, expansion of infrastructure, conversion into nature, and land abandonment. Increases in cropping intensity accounted for 42 Mha of additional harvested area. Together with increased co-product availability for animal feed, this was sufficient to increase the net harvested area (NHA, crop area harvested for food, feed, and fiber markets) in the study countries by 19 Mha. Thus, despite substantial expansion of biofuel production, more land has become available for non-fuel applications. Biofuel crop areas and NHA increased in most countries including the USA and Brazil. It is concluded that biofuel expansion in 2000-2010 is not associated with a decline in the NHA available for food crop production. The increases in multiple cropping have often been overlooked and should be considered more fully in calculations of (indirect) land-use change (iLUC). (c) 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Evaluation of two commercial, rapid, ELISA kits testing or scrapie in retro-pharyngeal lymph nodes in sheep
Kittelberger, R. ; McIntuyre, L. ; Watts, S. ; MacDiarmid, S. ; Hannah, M.J. ; Jenner, J. ; Bueno, R. ; Swainsbury, R. ; Langeveld, J.P.M. ; Keulen, L.J.M. van; Zijderveld, F.G. van; Wemheuer, W.M. ; Richt, J.A. ; Sorenson, S.J. ; Pigott, C.J. ; O'Keefe, J.S. - \ 2014
New Zealand Veterinary Journal 62 (2014)6. - ISSN 0048-0169 - p. 343 - 350.
natural scrapie - prion protein - immunohistochemical detection - new-zealand - prp - accumulation - diagnosis - genotypes - tissues - brain
AIMS: To estimate the number of cases of scrapie that would occur in sheep of different prion protein (PrP) genotypes if scrapie was to become established in New Zealand, and to compare the performance of two commercially available, rapid ELISA kits using ovine retro-pharyngeal lymph nodes (RLN) from non-infected and infected sheep of different PrP genotypes. METHODS: Using published data on the distribution of PrP genotypes within the New Zealand sheep flock and the prevalence of cases of scrapie in these genotypes in the United Kingdom, the annual expected number of cases of scrapie per genotype was estimated, should scrapie become established in New Zealand, assuming a total population of 28 million sheep. A non-infected panel of RLN was collected from 737 sheep from New Zealand that had been culled, found in extremis or died. Brain stem samples were also collected from 131 of these sheep. A second panel of infected samples comprised 218 and 117 RLN from confirmed scrapie cases that had originated in Europe and the United States of America, respectively. All samples were screened using two commercial, rapid, transmissible spongiform encephalopathy ELISA kits: Bio-Rad TeSeE ELISA (ELISA-BR), and IDEXX HerdChek BSE-Scrapie AG Test (ELISA-ID). RESULTS: If scrapie became established in New Zealand, an estimated 596 cases would occur per year; of these 234 (39%) and 271 (46%) would be in sheep carrying ARQ/ARQ and ARQ/VRQ PrP genotypes, respectively. For the non-infected samples from New Zealand the diagnostic specificity of both ELISA kits was 100%. When considering all infected samples, the diagnostic sensitivity was 70.4 (95% CI=65.3-75.3)% for ELISA-BR and 91.6 (95% CI=88.2-94.4)% for ELISA-ID. For the ARQ/ARQ genotype (n=195), sensitivity was 66.2% for ELISA-BR and 90.8% for ELISA-ID, and for the ARQ/VRQ genotype (n=107), sensitivity was 81.3% for ELISA-BR and 98.1% for ELISA-ID. CONCLUSIONS: In this study, the ELISA-ID kit demonstrated a higher diagnostic sensitivity for detecting scrapie in samples of RLN from sheep carrying scrapie-susceptible PrP genotypes than the ELISA-BR kit at comparable diagnostic specificity.
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