Yu Hai, Hua Rong-Hong, Wei Tian-Chao, Zhou Yan-Jun, Tian Zhi-Jun, Li Guo-Xin, Liu Tian-Qiang, Tong Guang-Zhi
National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
Vet Microbiol. 2008 Sep 18;131(1-2):82-92. doi: 10.1016/j.vetmic.2008.02.024. Epub 2008 Mar 6.
As pigs are susceptible to infection with both avian and human influenza A viruses, they have been proposed to be an intermediate host for the adaptation of avian influenza viruses to humans. In April 2006, a disease caused by highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) occurred in several pig farms and subsequently overwhelmed almost half of China with more than 2,000,000 cases of pig infection. Here we report a case in which four swine H9N2 influenza viruses were isolated from pigs infected by highly pathogenic PRRSVs in Guangxi province in China. All the eight gene segments of the four swine H9N2 viruses are highly homologous to A/Pigeon/Nanchang/2-0461/00 (H9N2) or A/Wild Duck/Nanchang/2-0480/00 (H9N2). Phylogenetic analyses of eight genes show that the swine H9N2 influenza viruses are of avian origin and may be the descendants of A/Duck/Hong Kong/Y280/97-like viruses. Molecular analysis of the HA gene indicates that our H9N2 isolates might have high-affinity binding to the alpha2,6-NeuAcGal receptor found in human cells. In conclusion, our finding provides further evidence about the interspecies transmission of avian influenza viruses to pigs and emphasizes the importance of reinforcing swine influenza virus (SIV) surveillance, especially after the emergence of highly pathogenic PRRSVs in pigs in China.
由于猪对禽流感 A 病毒和人流感 A 病毒均易感，因此它们被认为是禽流感病毒适应人类的中间宿主。2006 年 4 月，几个养猪场发生了由高致病性猪繁殖与呼吸综合征病毒（PRRSV）引起的疾病，随后疫情蔓延至中国近半数地区，猪感染病例超过 200 万例。在此，我们报告一例从中国广西感染高致病性 PRRSV 的猪中分离出四株猪源 H9N2 流感病毒的病例。这四株猪源 H9N2 病毒的所有八个基因片段均与 A/鸽子/南昌/2 - 0461/00（H9N2）或 A/野鸭/南昌/2 - 0480/00（H9N2）高度同源。对八个基因的系统发育分析表明，猪源 H9N2 流感病毒起源于禽类，可能是 A/鸭/香港/Y280/97 样病毒的后代。对 HA 基因的分子分析表明，我们分离的 H9N2 毒株可能与人细胞中发现的α2,6 - NeuAcGal 受体具有高亲和力结合。总之，我们的发现为禽流感病毒跨物种传播至猪提供了进一步证据，并强调了加强猪流感病毒（SIV）监测的重要性，尤其是在中国猪群中出现高致病性 PRRSV 之后。
