Reiner Gerald
Department of Veterinary Clinical Sciences, Swine Clinic, Justus-Liebig-University, Frankfurter Strasse 112, 35392 Giessen, Germany.
Porcine Health Manag. 2016 Nov 16;2:27. doi: 10.1186/s40813-016-0045-y. eCollection 2016.
PRRS is one of the most challenging diseases for world-wide pig production. Attempts for a sustainable control of this scourge by vaccination have not yet fully satisfied. With an increasing knowledge and methodology in disease resistance, a new world-wide endeavour has been started to support the combat of animal diseases, based on the existence of valuable gene variants with regard to any host-pathogen interaction. Several groups have produced a wealth of evidence for natural variability in resistance/susceptibility to PRRS in our commercial breeding lines. However, up to now, exploiting existing variation has failed because of the difficulty to detect the carriers of favourable and unfavourable alleles, especially with regard to such complex polygenic traits like resistance to PRRS. New hope comes from new genomic tools like next generation sequencing which have become extremely fast and low priced. Thus, research is booming world-wide and the jigsaw puzzle is filling up - slowly but steadily. On the other hand, knowledge from virological and biomedical basic research has opened the way for an "intervening way", i.e. the modification of identified key genes that occupy key positions in PRRS pathogenesis, like was identified as the striking receptor in PRRSV entry and its knockout from the genome by gene editing has led to the production of pigs that were completely resistant to PRRSV - a milestone in modern pig breeding. However, at this early step, concerns remain about the acceptance of societies for gene edited products and regulation still awaits upgrading to the new technology. Further questions arise with regard to upcoming patents from an ethical and legal point of view. Eventually, the importance of for homeostasis, defence and immunity demands for more insight before its complete or partial silencing can be answered. Whatever path will be followed, even a partial abolishment of PRRSV replication will lead to a significant improvement of the disastrous herd situation, with a significant impact on welfare, performance, antimicrobial consumption and consumer protection. Genetics will be part of a future solution.
猪繁殖与呼吸综合征（PRRS）是全球养猪业面临的最具挑战性的疾病之一。通过疫苗接种实现对这一祸害的可持续控制的尝试尚未完全令人满意。随着抗病性知识和方法的不断增加，基于宿主与病原体相互作用中存在有价值的基因变异，一项新的全球努力已经启动，以支持动物疾病的防治。几个研究小组已经提供了大量证据，证明我们商业育种品系对PRRS的抗性/易感性存在自然变异。然而，到目前为止，由于难以检测有利和不利等位基因的携带者，特别是对于像对PRRS的抗性这样复杂的多基因性状，利用现有变异的努力失败了。新的希望来自于新一代测序等新的基因组工具，这些工具已经变得极其快速且价格低廉。因此，全球范围内的研究蓬勃发展，拼图正在慢慢但稳步地拼凑完整。另一方面，病毒学和生物医学基础研究的知识为一种“干预方法”开辟了道路，即对在PRRS发病机制中占据关键位置的已鉴定关键基因进行修饰，例如被确定为PRRS病毒进入的显著受体，通过基因编辑从基因组中敲除该受体已导致产生对PRRS病毒完全抗性的猪——这是现代养猪育种中的一个里程碑。然而，在这个早期阶段，社会对基因编辑产品的接受度仍然存在担忧，监管仍有待升级以适应这项新技术。从伦理和法律角度来看，即将到来的专利也引发了进一步的问题。最终，在能够回答其完全或部分沉默之前，需要对其在体内平衡、防御和免疫方面的重要性有更多的了解。无论采取何种途径，即使是部分消除PRRS病毒的复制也将导致灾难性猪群状况的显著改善，对动物福利、生产性能、抗菌药物使用和消费者保护产生重大影响。遗传学将成为未来解决方案的一部分。
