Scrapie prevalence in sheep of susceptible genotype is declining in a population subject to breeding for resistance

T.H.J. Hagenaars, M.B. Melchior, A. Bossers, A. Davidse, B. Engel, F.G. van Zijderveld

Research output: Contribution to journalArticleAcademicpeer-review

34 Citations (Scopus)

Abstract

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.
LanguageEnglish
Article number25
JournalBMC Veterinary Research
Volume6
DOIs
Publication statusPublished - 2010

Fingerprint

Scrapie
scrapie
Breeding
Sheep
Genotype
sheep
genotype
breeding
Population
selection methods
flocks
monitoring
Genetic Selection
animal breeding
genetic resistance
prions
relative risk
Netherlands
control methods
animals

Keywords

  • great-britain
  • british sheep
  • classical scrapie
  • active surveillance
  • prp genotype
  • flock
  • program
  • risk
  • bse
  • epidemiology

Cite this

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title = "Scrapie prevalence in sheep of susceptible genotype is declining in a population subject to breeding for resistance",
abstract = "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.",
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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.; van Zijderveld, F.G.

In: BMC Veterinary Research, Vol. 6, 25, 2010.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Scrapie prevalence in sheep of susceptible genotype is declining in a population subject to breeding for resistance

AU - Hagenaars, T.H.J.

AU - Melchior, M.B.

AU - Bossers, A.

AU - Davidse, A.

AU - Engel, B.

AU - van Zijderveld, F.G.

PY - 2010

Y1 - 2010

N2 - 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.

AB - 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.

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