In vitro and in vivo characteristics of the recombinant viruses.

aMDT (mean death time), average number of hours required to kill the inoculated eggs.bAccording to the criteria set by OIE for evaluating the pathogenesis in chickens, the viruses with an IVPI value greater than 1.2 are defined as highly pathogenic avian influenza virus (HPAIV), or are defined as low pathogenic avian influenza virus (LPAIV).cNumber of birds that died/number of birds inoculated.dThe mean virus titer was expressed as the log10 PFU/ml±standard deviation. “-”, virus was not recovered from the cloacal swabs in inoculated chickens on day 3 p.i.a aMDT（平均死亡时间，mean death time）：指杀灭接种禽卵所需的平均小时数。b 依据世界动物卫生组织（OIE）制定的鸡源病毒致病性评估标准，静脉致病指数（IVPI，Intravenous Pathogenicity Index）大于1.2的病毒被定义为高致病性禽流感病毒（HPAIV，highly pathogenic avian influenza virus），其余病毒则归类为低致病性禽流感病毒（LPAIV，low pathogenic avian influenza virus）。c 死亡禽只数与接种禽只数的比值。d 平均病毒滴度以log₁₀ PFU/ml±标准差的形式表示。其中符号"-"代表感染后第3天（p.i.，post infection），未从接种鸡只的泄殖腔拭子中分离得到病毒。