Data_Sheet_1_Isolation, identification, recombination analysis and pathogenicity experiment of a PRRSV recombinant strain in Sichuan Province, China.DOCX

Since 2013, the porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2), lineage 1.8 (NADC30-like PRRSV) has emerged and become widely prevalent in China. The NADC30-like PRRSV poses significant challenges for disease control, primarily because of its propensity for frequent mutations and recombinations. We successfully isolated and identified a NADC30-like strain, designated SCCD22, in Chengdu, Sichuan Province, China. We meticulously examined the genetic recombination properties and evaluated its pathogenicity in 28-day-old piglets. SCCD22 showed 93.02% nucleotide homology with the NADC30 PRRSV strain, and its non-structural protein 2 coding region showed the same 131 amino acid deletion pattern as that seen in NADC30. Furthermore, we identified two recombination events in SCCD22: one in the NSP2 region (1,028–3,290 nt), where it was highly similar to the JXA1-like strain GZ106; and another in the NSP10 ~ 12 region (9,985–12,279 nt), closely resembling the NADC30-like strain CY2-1604. Piglets infected with SCCD22 exhibited clinical symptoms such as elevated body temperature, prolonged fever, reduced appetite, and roughened fur. Postmortem examinations underscored the typical lung pathology associated with PRRSV, indicating that the lungs were the primary affected organs. Furthermore, extended viral shedding accompanied by progressive viremia was observed in the serum and nasal excretions of infected piglets. In summary, this study reports a domestic PRRSV recombination strain in the Sichuan Province that can provide critical insights into preventing and controlling PRRSV in this region.

自2013年以来，猪繁殖与呼吸综合征病毒2型（PRRSV-2）谱系1.8（NADC30样猪繁殖与呼吸综合征病毒）在中国出现并广泛流行。NADC30样猪繁殖与呼吸综合征病毒给疾病防控带来了严峻挑战，究其原因主要是其易于发生频繁突变与重组。本研究成功分离并鉴定了一株命名为SCCD22的NADC30样毒株，该毒株采自中国四川省成都市。我们对其遗传重组特性进行了细致分析，并评估了其对28日龄仔猪的致病性。SCCD22与NADC30猪繁殖与呼吸综合征病毒毒株的核苷酸同源性为93.02%，其非结构蛋白2（NSP2）编码区与NADC30一样，存在131个氨基酸的缺失模式。此外，我们在SCCD22中发现了两次重组事件：一次位于NSP2区域（1028–3290 nt），该区域与JXA1样毒株GZ106高度相似；另一次位于NSP10~12区域（9985–12279 nt），与NADC30样毒株CY2-1604极为相似。感染SCCD22的仔猪出现了体温升高、持续发热、食欲减退及被毛粗乱等临床症状。剖检结果显示其出现了猪繁殖与呼吸综合征典型的肺部病理变化，表明肺部是主要受侵害的器官。此外，感染仔猪的血清与鼻腔分泌物中可检测到持续的病毒排毒，并伴随进行性病毒血症。综上，本研究报道了一株四川省本土的猪繁殖与呼吸综合征病毒重组毒株，该毒株可为该地区的猪繁殖与呼吸综合征防控工作提供关键参考依据。