两株EA H1N1亚型猪流感病毒在豚鼠体内的复制和传播能力评估

Evaluation of replication and droplet transmissibility of two Eurasian avian-like H1N1 swine influenza viruses in guinea pigs

为评价欧亚类禽H1N1(EA H1N1)亚型猪流感病毒(SIV)在哺乳动物间呼吸道飞沫的传播能力,本研究选取A/swine/Henan/11/2005(H1N1)(He N11)和A/swine/Hunan/26/2010(H1N1)(HuN26)为代表病毒株,以106EID50/300μL的剂量,经鼻腔分别感染3只豚鼠,24 h后在相邻笼内分别放入3只豚鼠作为传播组,通过检测鼻洗液内的病毒滴度评价2株病毒在豚鼠间呼吸道飞沫的传播能力;并以相同剂量分别感染2只豚鼠,感染72 h后通过检测脏器内病毒滴度评价2株病毒在豚鼠体内的复制能力。传播试验结果表明,HeN11株在豚鼠间的传播能力为3传1,HuN26株为3传3。脏器中病毒滴定结果表明,HeN11株在下呼吸道具有良好的复制能力,而HuN26株主要在上呼吸道复制。进一步的氨基酸差异分析表明,2株病毒株共有62个氨基酸差异。以上结果表明,2株病毒株均能够在豚鼠呼吸道内进行不同程度的复制,而呼吸道飞沫传播能力显著不同。本实验为进一步研究EA H1N1 SIV在哺乳动物间呼吸道飞沫传播的分子机制奠定基础,也为猪流感的防控提供了实验依据。

To evaluate the respiratory droplet transmissibility and replication of two representative Eurasian avian-like H1N1 subtype swine influenza viruses （SIV） of A/swine/Henardl 1/2005 （HEN11） and A/swine/Hunard26/2010 （HUN26）, the guinea pigs in two inoculated groups （3 in each） were intranasally inoculated with each of the virus at a dosage of l06 EID^300 ILL, respectively, and the other guinea pigs in two exposed groups （3 in each） were put in adjacent cages of inoculated groups at 24 hrs post the inoculations to examine the respiratory droplet transmissibility by detecting viral titers in nasal wash and the antibody from guinea pigs in exposed groups. In addition, the virus replications were also examined from the nasal wash, tracheas and lungs in the inoculated guinea pigs at 72 hrs post inoculation. The results showed that HeN11 only transmitted to one of three guinea pigs, while HUN26 transmitted to all of three guinea pigs. Moreover, HeN11 was detected mainly in the lower respiratory tract, while HUN26 replicated to a high titer in the upper respiratory tract. Further analysis indicated that there were 62 amino acid differences between these two strains. In summary, both HeN11 and HUN26 replicated to different levels in respiratory tract of guinea pigs, and their droplet tmnsmissibility between guinea pigs were significantly different. This study laid foundation to further explore the molecular mechanism of EA H1N1 subtype SIV respiratory droplet transmissibility between mammals.