Li Xuyong, Shi Jianzhong, Guo Jing, Deng Guohua, Zhang Qianyi, Wang Jinliang, He Xijun, Wang Kaicheng, Chen Jiming, Li Yuanyuan, Fan Jun, Kong Huiui, Gu Chunyang, Guan Yuantao, Suzuki Yasuo, Kawaoka Yoshihiro, Liu Liling, Jiang Yongping, Tian Guobin, Li Yanbing, Bu Zhigao, Chen Hualan
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China; State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China.
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
PLoS Pathog. 2014 Nov 20;10(11):e1004508. doi: 10.1371/journal.ppat.1004508. eCollection 2014 Nov.
H9N2 subtype influenza viruses have been detected in different species of wild birds and domestic poultry in many countries for several decades. Because these viruses are of low pathogenicity in poultry, their eradication is not a priority for animal disease control in many countries, which has allowed them to continue to evolve and spread. Here, we characterized the genetic variation, receptor-binding specificity, replication capability, and transmission in mammals of a series of H9N2 influenza viruses that were detected in live poultry markets in southern China between 2009 and 2013. Thirty-five viruses represented 17 genotypes on the basis of genomic diversity, and one specific "internal-gene-combination" predominated among the H9N2 viruses. This gene combination was also present in the H7N9 and H10N8 viruses that have infected humans in China. All of the 35 viruses preferentially bound to the human-like receptor, although two also retained the ability to bind to the avian-like receptor. Six of nine viruses tested were transmissible in ferrets by respiratory droplet; two were highly transmissible. Some H9N2 viruses readily acquired the 627K or 701N mutation in their PB2 gene upon infection of ferrets, further enhancing their virulence and transmission in mammals. Our study indicates that the widespread dissemination of H9N2 viruses poses a threat to human health not only because of the potential of these viruses to cause an influenza pandemic, but also because they can function as "vehicles" to deliver different subtypes of influenza viruses from avian species to humans.
几十年来，许多国家在不同种类的野生鸟类和家禽中都检测到了H9N2亚型流感病毒。由于这些病毒在家禽中致病性较低，在许多国家，消灭这些病毒并非动物疾病控制的优先事项，这使得它们得以继续进化和传播。在此，我们对2009年至2013年间在中国南方活禽市场检测到的一系列H9N2流感病毒的基因变异、受体结合特异性、复制能力及在哺乳动物中的传播情况进行了表征。基于基因组多样性，35种病毒代表了17种基因型，且一种特定的“内部基因组合”在H9N2病毒中占主导地位。这种基因组合也存在于在中国感染人类的H7N9和H10N8病毒中。所有35种病毒都优先结合人源样受体，不过其中两种病毒也保留了结合禽源样受体的能力。所检测的9种病毒中有6种可通过呼吸道飞沫在雪貂中传播；两种具有高度传染性。一些H9N2病毒在感染雪貂后其PB2基因很容易获得627K或701N突变，进一步增强了它们在哺乳动物中的毒力和传播能力。我们的研究表明，H9N2病毒的广泛传播对人类健康构成威胁，不仅因为这些病毒有可能引发流感大流行，还因为它们可充当“载体”，将不同亚型的流感病毒从禽类传播给人类。
