Melchior M B, Hagenaars T J, Davidse A, van Keulen L J M, Bossers A, van Zijderveld F G
Centraal Veterinair Instituut van Wageningen UR, Postbus 65, 8200 A B Lelystad.
Tijdschr Diergeneeskd. 2011 Feb 1;136(2):84-93.
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.
绵羊对羊瘙痒病的易感性受动物朊病毒蛋白(PrP)基因型的调控。1998年,荷兰启动了一项雄心勃勃的自愿性羊瘙痒病防控计划,该计划基于选择具有ARR/ARR基因型的公羊用于繁殖。2004年该计划变为强制性计划;自2007年起又恢复为自愿性计划。我们监测了2002年至2010年6月期间荷兰绵羊群体中PrP基因型频率的流行情况以及羊瘙痒病的流行情况。结果显示,选择抗羊瘙痒病的绵羊使得荷兰全国羊群中ARR等位基因频率从2005年的37.5%增加到2009年的61.4%。此外,监测数据表明,在强制性繁殖计划开始几年后,羊瘙痒病的流行率显著下降,从2004年的超过0.2%降至2009年的0.015%。这种下降是荷兰绵羊群体中抗羊瘙痒病绵羊数量增加的结果。迄今为止,基于这些数据的结果和模型表明,为了成功根除羊瘙痒病,选择性育种计划应持续数年。在未来几年监测荷兰绵羊群体中的PrP频率和羊瘙痒病流行情况将很重要。