WUR0000125 PRRS 抗性 SNP 对新型传播试验中猪的感染性和易感性没有明显影响。

The WUR0000125 PRRS resilience SNP had no apparent effect on pigs' infectivity and susceptibility in a novel transmission trial.

机构信息

The Roslin Institute, University of Edinburgh, Easter Bush, Roslin, Edinburgh, UK.

Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.

出版信息

Genet Sel Evol. 2023 Jul 24;55(1):51. doi: 10.1186/s12711-023-00824-z.

DOI:10.1186/s12711-023-00824-z

PMID:37488481

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10364427/

Abstract

BACKGROUND

Porcine reproductive and respiratory syndrome (PRRS) remains one of the most important infectious diseases for the pig industry. A novel small-scale transmission experiment was designed to assess whether the WUR0000125 (WUR for Wageningen University and Research) PRRS resilience single nucleotide polymorphism (SNP) confers lower susceptibility and infectivity to pigs under natural porcine reproductive and respiratory syndrome virus (PRRSV-2) transmission.

METHODS

Commercial full- and half-sib piglets (n = 164) were assigned as either Inoculation, Shedder, or Contact pigs. Pigs were grouped according to their relatedness structure and WUR genotype, with R- and R+ referring to pigs with zero and one copy of the dominant WUR resilience allele, respectively. Barcoding of the PRRSV-2 strain (SD09-200) was applied to track pig genotype-specific transmission. Blood and nasal swab samples were collected and concentrations of PRRSV-2 were determined by quantitative (q)-PCR and cell culture and expressed in units of median tissue culture infectious dose (TCID). The LogTCID at each sampling event, derived infection status, and area under the curve (AUC) were response variables in linear and generalized linear mixed models to infer WUR genotype differences in Contact pig susceptibility and Shedder pig infectivity.

RESULTS

All Shedder and Contact pigs, except one, became infected through natural transmission. There was no significant (p > 0.05) effect of Contact pig genotype on any virus measures that would indicate WUR genotype differences in susceptibility. Contact pigs tended to have higher serum AUC (p = 0.017) and logTCID (p = 0.034) when infected by an R+ shedder, potentially due to more infectious R+ shedders at the early stages of the transmission trial. However, no significant Shedder genotype effect was found in serum (p = 0.274) or nasal secretion (p = 0.951) that would indicate genotype differences in infectivity.

CONCLUSIONS

The novel design demonstrated that it is possible to estimate genotype effects on Shedder pig infectivity and Contact pig susceptibility that are not confounded by family effects. The study, however, provided no supportive evidence that genetic selection on WUR genotype would affect PRRSV-2 transmission. The results of this study need to be independently validated in a larger trial using different PRRSV strains before dismissing the effects of the WUR marker or the previously detected GBP5 gene on PRRSV transmission.

摘要

背景

猪繁殖与呼吸综合征（PRRS）仍然是养猪业最重要的传染病之一。本研究设计了一个新的小规模传播实验，旨在评估 Wageningen 大学和研究（WUR）的 PRRS 抗性单核苷酸多态性（SNP）WUR0000125 是否会降低猪在自然感染猪繁殖与呼吸综合征病毒（PRRSV-2）时的易感性和感染性。

方法

将商业全同胞和半同胞仔猪（n=164）分为接种组、排毒组和接触组。根据亲缘关系结构和 WUR 基因型对猪进行分组，其中 R-和 R+分别表示猪携带零个和一个优势 WUR 抗性等位基因。对 PRRSV-2 株（SD09-200）进行条形码标记，以跟踪猪基因型特异性传播。采集血液和鼻腔拭子样本，并通过定量（q）-PCR 和细胞培养确定 PRRSV-2 的浓度，并以组织培养感染剂量（TCID）的中位数表示。每个采样事件的 LogTCID、推断的感染状态和曲线下面积（AUC）是线性和广义线性混合模型的响应变量，以推断接触猪易感性和排毒猪感染性的 WUR 基因型差异。

结果

除了一只猪之外，所有的排毒和接触猪都通过自然传播感染了病毒。接触猪的基因型对任何病毒指标均无显著影响（p>0.05），这表明 WUR 基因型在易感性方面没有差异。当接触的猪感染了 R+排毒猪时，其血清 AUC（p=0.017）和 logTCID（p=0.034）更高，这可能是由于在传播试验的早期阶段传染性更强的 R+排毒猪更多。然而，在血清（p=0.274）或鼻腔分泌物（p=0.951）中，没有发现显著的排毒猪基因型效应，这表明在感染性方面基因型没有差异。

结论

该新设计表明，在不受家族效应影响的情况下，估计基因型对排毒猪感染性和接触猪易感性的影响是可行的。然而，本研究没有提供支持性证据表明，对 WUR 基因型的遗传选择会影响 PRRSV-2 的传播。在排除 WUR 标记或之前检测到的 GBP5 基因对 PRRSV 传播的影响之前，需要在使用不同 PRRSV 株的更大规模试验中独立验证本研究的结果。