Breeding with resistant rams leads to rapid control of classical scrapie in affected sheep flocks

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Scopus)

Abstract

Susceptibility to scrapie, a transmissible spongiform encephalopathy in sheep, is modulated by the genetic make-up of the sheep. Scrapie control policies, based on selecting animals of resistant genotype for breeding, have recently been adopted by the Netherlands and other European countries. Here we assess the effectiveness of a breeding programme based on selecting rams of resistant genotype to obtain outbreak control in classical scrapie-affected sheep flocks under field conditions. In six commercially-run flocks following this breeding strategy, we used genotyping to monitor the genotype distribution, and tonsil biopsies and post-mortem analyses to monitor the occurrence of scrapie infection. The farmers were not informed about the monitoring results until the end of the study period of six years. We used a mathematical model of scrapie transmission to analyze the monitoring data and found that where the breeding scheme was consistently applied, outbreak control was obtained after at most four years. Our results also show that classical scrapie control can be obtained before the frequency of non-resistant animals is reduced to zero in the flock. This suggests that control at the national scale can be obtained without a loss of genetic polymorphisms from any of the sheep breeds
LanguageEnglish
Article number5
Number of pages11
JournalVeterinary Research
Volume42
Issue number1
DOIs
Publication statusPublished - 2011

Fingerprint

Scrapie
scrapie
rams
Breeding
Sheep
flocks
sheep
breeding
monitoring
Genotype
Disease Outbreaks
genotype
Prion Diseases
prion diseases
tonsils
Palatine Tonsil
sheep breeds
Genetic Polymorphisms
Netherlands
genotyping

Keywords

  • natural scrapie
  • prion protein
  • prp genotype
  • british sheep
  • immunohistochemical detection
  • clinical signs
  • transmission
  • bse
  • dynamics
  • gene

Cite this

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title = "Breeding with resistant rams leads to rapid control of classical scrapie in affected sheep flocks",
abstract = "Susceptibility to scrapie, a transmissible spongiform encephalopathy in sheep, is modulated by the genetic make-up of the sheep. Scrapie control policies, based on selecting animals of resistant genotype for breeding, have recently been adopted by the Netherlands and other European countries. Here we assess the effectiveness of a breeding programme based on selecting rams of resistant genotype to obtain outbreak control in classical scrapie-affected sheep flocks under field conditions. In six commercially-run flocks following this breeding strategy, we used genotyping to monitor the genotype distribution, and tonsil biopsies and post-mortem analyses to monitor the occurrence of scrapie infection. The farmers were not informed about the monitoring results until the end of the study period of six years. We used a mathematical model of scrapie transmission to analyze the monitoring data and found that where the breeding scheme was consistently applied, outbreak control was obtained after at most four years. Our results also show that classical scrapie control can be obtained before the frequency of non-resistant animals is reduced to zero in the flock. This suggests that control at the national scale can be obtained without a loss of genetic polymorphisms from any of the sheep breeds",
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author = "G. Nodelijk and {van Roermund}, H.J.W. and {van Keulen}, L.J.M. and B. Engel and P. Vellema and T.H.J. Hagenaars",
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Breeding with resistant rams leads to rapid control of classical scrapie in affected sheep flocks. / Nodelijk, G.; van Roermund, H.J.W.; van Keulen, L.J.M.; Engel, B.; Vellema, P.; Hagenaars, T.H.J.

In: Veterinary Research, Vol. 42, No. 1, 5, 2011.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - Nodelijk, G.

AU - van Roermund, H.J.W.

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AU - Engel, B.

AU - Vellema, P.

AU - Hagenaars, T.H.J.

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AB - Susceptibility to scrapie, a transmissible spongiform encephalopathy in sheep, is modulated by the genetic make-up of the sheep. Scrapie control policies, based on selecting animals of resistant genotype for breeding, have recently been adopted by the Netherlands and other European countries. Here we assess the effectiveness of a breeding programme based on selecting rams of resistant genotype to obtain outbreak control in classical scrapie-affected sheep flocks under field conditions. In six commercially-run flocks following this breeding strategy, we used genotyping to monitor the genotype distribution, and tonsil biopsies and post-mortem analyses to monitor the occurrence of scrapie infection. The farmers were not informed about the monitoring results until the end of the study period of six years. We used a mathematical model of scrapie transmission to analyze the monitoring data and found that where the breeding scheme was consistently applied, outbreak control was obtained after at most four years. Our results also show that classical scrapie control can be obtained before the frequency of non-resistant animals is reduced to zero in the flock. This suggests that control at the national scale can be obtained without a loss of genetic polymorphisms from any of the sheep breeds

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