Department of Veterinary Culture Collection, China Institute of Veterinary Drug Control, 8 Nandajie, Zhongguancun, Haidian District, Beijing 100081, China.
Viruses. 2020 Jan 2;12(1):55. doi: 10.3390/v12010055.
Swine influenza virus causes a substantial disease burden to swine populations worldwide and poses an imminent threat to the swine industry and humans. Given its importance, we characterized two swine influenza viruses isolated from Shandong, China. The homology and phylogenetic analyses showed that all eight gene segments of A/swine/Shandong/AV1522/2011(H1N1) were closely related to A/Maryland/12/1991(H1N1) circulating in North America. The HA, NA, M, and NS genes of the isolate were also confirmed to have a high homology to A/swine/Hubei/02/2008(H1N1) which appeared in China in 2008, and the virus was clustered into the classical swine lineage. The gene segments of A/swine/Shandong/AV1523/2011(H1N1) were highly homologous to the early human H1N1 and H2N2 influenza viruses, except for the HA gene, and the virus was a reassortant H1N1 virus containing genes from the classical swine (HA) and human (NA, PB2, PB1, PA, NP, M, and NS) lineages. Both the viruses could cause lethal infection and replicate efficiently in the lungs, brains, spleens, and kidneys of mice. Histopathological examinations showed that AV1522 and AV1523 viruses caused a spectrum of marked pneumonia and meningoencephalitis according to the duration of infection, demonstrating a progression of respiratory disease and neurological disease over the course of infection that ultimately resulted in lethality for the infected mice. The changes in the pathogenicity of swine influenza viruses to mammals, accompanied with the continuous reassortment and evolution of the viruses, highlights the importance of ongoing epidemiological investigation.
猪流感病毒对全球猪群造成了巨大的疾病负担，并对养猪业和人类构成了迫在眉睫的威胁。鉴于其重要性，我们对分离自中国山东的两株猪流感病毒进行了鉴定。同源性和系统进化分析表明，A/swine/Shandong/AV1522/2011(H1N1)的八个基因片段均与在北美流行的 A/Maryland/12/1991(H1N1)密切相关。该分离株的 HA、NA、M 和 NS 基因也与 2008 年在中国出现的 A/swine/Hubei/02/2008(H1N1)具有高度同源性，该病毒聚类于经典猪流感谱系。A/swine/Shandong/AV1523/2011(H1N1)的基因片段除 HA 基因外，与早期的人 H1N1 和 H2N2 流感病毒高度同源，该病毒是一种含有经典猪（HA）和人（NA、PB2、PB1、PA、NP、M 和 NS）谱系基因的重配 H1N1 病毒。这两种病毒均能在小鼠的肺、脑、脾和肾中引起致死性感染和高效复制。组织病理学检查显示，AV1522 和 AV1523 病毒根据感染时间的长短引起了不同程度的显著肺炎和脑膜脑炎，表明在感染过程中呼吸道疾病和神经疾病呈进展性，最终导致感染小鼠死亡。猪流感病毒对哺乳动物致病性的变化，伴随着病毒的持续重组和进化，凸显了持续进行流行病学调查的重要性。
