H7N9禽流感病毒与其他流感病毒对雪貂致病性与传播力的比较

目的 针对2013年3月中国爆发的人感染H7N9禽流感病毒，在雪貂体内进行致病性及传播力的研究，并与甲型H1N1流感病毒、H5N1禽流感病毒进行比较。方法 对新发H7N9毒株、甲型H1N1流感病毒、H5N1禽流感病毒感染雪貂后的临床症状、体征，呼吸道排毒情况，组织病理学变化等进行评价和比较，并对H7N9毒株在雪貂群体中的传播力进行研究。结果 雪貂模型的临床症状、死亡率、病毒传播以及组织病理学分析显示：H7N9病毒的致病性低于H5N1，与2009年起源于北美的甲型H1N1流感病毒相当。新发H7N9禽流感病毒可以在雪貂的呼吸道、心脏、肝脏以及嗅球进行复制。值得注意的是H7N9禽流感可以通过飞沫在雪貂间进行低水平的传播，并且在传播过程中，病毒基因组内有多个位点的氨基酸发生了替换。结论 H7N9禽流感病毒对雪貂的致病性较H5N1禽流感病毒低，与甲型H1N1流感病毒对雪貂的致病性相当，H7N9禽流感病毒可在雪貂间进行传播。

Comparison of pathogenicity and transmissibility of the novel avian-origin human A (H7N9) influenza virus and other strains in ferrets

Objective the novel avian-origin H7N9 subtype influenza virus caused outbreak of human infections in China since March 2013. The aim of this study was to better understand the pathogenicity and transmissibility of the H7N9 influenza virus in ferrets to verify whether this new emerging infectious H7N9 virus can infect humans, and to compare the transmission ability of this virus with that of other influenza virus subtypes in ferrets. Methods A/Anhui/1/2013 (H7N9) virus was administered by intranasal instillation to groups of ferrets. Clinical signs, virus shedding from respiratory tract and pathological changes were recorded. Meanwhile, the replication ability, virulence and pathogenicity were investigated in ferret models and compared with those of 2009 pandemic H1N1 and H5N1 influenza viruses. Results In the ferret models, based on the clinical signs, mortality, virus dissemination, and pathological analysis, the H7N9 influenza virus was found to be less pathogenic than the H5N1 virus but was comparable with the 2009 pandemic H1N1 virus. The H7N9 virus could replicate in the upper and lower respiratory tract, heart, liver, and olfactory bulb. It is worth noting that the H7N9 virus exhibited low level of transmission between ferrets via respiratory droplets. There were four mutations in the virus isolated from the contact ferrets. Conclusions These data indicate that H7N9 subtype influenza virus is transmissible among ferrets, and the pathogenicity of avian-origin H7N9 subtype influenza virus is lower than that of H5N1 subtype influenza virus between ferrets, and is comparable to that of H1N1 influenza virus.