自2018年以来,新出现的亚谱系1.5(NADC34样)猪繁殖与呼吸综合征病毒(PRRSV)对中国养猪业构成了直接威胁。然而,NADC34样PRRSV在中国猪场的患病率和影响尚不清楚.在本研究中,我们持续监测病原体,包括PRRSV,非洲猪瘟病毒(ASFV)经典猪瘟病毒(CSFV),伪狂犬病病毒(PRV),和猪圆环病毒2(PCV2)-在黑龙江省具有严格生物安全措施的育肥猪场上,中国,从2020年到2021年。结果表明,单一猪场上存在多种类型的PRRSV。NADC30样和NADC34样PRRSV是该猪场的主要菌株。重要的是,在高峰死亡率期间检测到的NADC34样PRRSV是该猪场的主要菌株之一。序列比对表明,这些菌株在NSP2蛋白中共享与2014年从美国(U.S.)分离的IA/2014/NADC34相同的100个氨基酸缺失。基于开放阅读框5(ORF5)的系统发育分析表明,该农场NADC34样PRRSV的遗传多样性相对单一,但是它的进化速度相对较高。限制性片段长度多态性(RFLP)模式分析显示,几乎所有ORF5RFLP均为1-7-4,其中1-4-4。此外,对NADC34样PRRSV的两个完整基因组进行了测序。重组分析和序列比对表明两种病毒,具有98.9%的核苷酸相似性,是非重组病毒。本研究首次报道了NADC34样PRRSV在中国北方某大型养殖场的流行情况和特征。这些结果将有助于揭示NADC34类PRRSV对中国猪场的影响,为NADC34类PRRSV的检测和进一步防控提供参考。
The newly emerged sublineage 1.5 (NADC34-like) porcine reproductive and respiratory syndrome virus (PRRSV) has posed a direct threat to the Chinese pig industry since 2018. However, the prevalence and impact of NADC34-like PRRSV on Chinese pig farms is unclear. In the present study, we continuously monitored pathogens-including PRRSV, African swine fever virus (ASFV), classical swine fever virus (CSFV), pseudorabies virus (PRV), and porcine circovirus 2 (PCV2)-on a fattening pig farm with strict biosecurity practices located in Heilongjiang Province,
China, from 2020 to 2021. The results showed that multiple types of PRRSV coexisted on a single pig farm. NADC30-like and NADC34-like PRRSVs were the predominant strains on this pig farm. Importantly, NADC34-like PRRSV-detected during the period of peak mortality-was one of the predominant strains on this pig farm. Sequence alignment suggested that these strains shared the same 100 aa deletion in the NSP2 protein as IA/2014/NADC34 isolated from the United States (U.S.) in 2014. Phylogenetic analysis based on open reading frame 5 (ORF5) showed that the genetic diversity of NADC34-like PRRSV on this farm was relatively singular, but it had a relatively high rate of evolution. Restriction fragment length polymorphism (
RFLP) pattern analysis showed that almost all ORF5 RFLPs were 1-7-4, with one 1-4-4. In addition, two complete genomes of NADC34-like PRRSVs were sequenced. Recombination analysis and sequence alignment demonstrated that both viruses, with 98.9% nucleotide similarity, were non-recombinant viruses. This study reports the prevalence and characteristics of NADC34-like PRRSVs on a large-scale breeding farm in northern
China for the first time. These results will help to reveal the impact of NADC34-like PRRSVs on Chinese pig farms, and provide a reference for the detection and further prevention and control of NADC34-like PRRSVs.