Evaluation of Transmission Route and Replication Efficiency of H9N2 Avian Influenza Virus
Evaluation of Transmission Route and Replication Efficiency of H9N2 Avian Influenza Virus
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DOI：
10.1637/8937-052809-reg.1
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发表时间：
2010-03-01
期刊：
影响因子：
1.4
通讯作者：
Liu, Xiufan
中科院分区：
文献类型：
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作者：
Shi, Huoying;Ashraf, Shamaila;Liu, Xiufan
A/Chicken/Beijing/1/94 （Ck/BJ/1/94）禽流感病毒与A/Chicken/Shanghai/F/98 （Ck/SH/F/98; H9N2）禽流感病毒的血凝素（HA）和神经氨酸酶（NA）基因在系统发育上相似，是H9N2亚型的一个原型。为了了解HA和NA基因在H9N2 AIV空气传播中的作用，我们比较了这两种病毒在无特定病原体鸡体内的传播途径和相对复制效率。采用反向遗传的方法合成了3个重组病毒，分别含有A/Chicken/Guangdong/SS/94 （Ck/GD/SS/94）的HA和NA基因（或两者都含有），其内部基因来源于Ck/SH/F/98。接种鸡与未接种鸡直接或间接接触，监测病毒脱落和滴度。结果表明，Ck/GD/SS/94不具有间接接触传播能力，而Ck/SH/F/98具有间接接触传播能力。重组病毒（RF/SSHA）内部含有Ck/SH/F/98基因和Ck/GD/SS/94 HA基因，其在肺组织中的病毒滴度较亲本毒株降低。有趣的是，用Ck/GD/SS/94替换Ck/SH/F/98的NA基因，或同时替换NA和HA基因，完全消除了重组RF/SSNA和RF/SSHA/SSNA的空气传播。由此可见，Ck/SH/F/98在鸡的呼吸道中具有较高的空气传播能力和复制效率。结果表明，Ck/SH/F/98的NA基因可以影响病毒的复制，从而间接影响这些病毒基因群的传播。
A/Chicken/Beijing/1/94 (Ck/BJ/1/94) avian influenza virus (AIV), a prototype of the H9N2 subtype, is phylogenetically similar in its hemagglutinin (HA) and neuraminidase (NA) genes to A/Chicken/Shanghai/F/98 (Ck/SH/F/98; H9N2) AIV, a natural reassortant between different sublineages. To understand the role of HA and NA genes in the airborne transmission of H9N2 AIV, we compared the transmission route and the relative replication efficiency of these strains in specific-pathogen-free chickens. Three recombinant viruses were generated by reverse genetics, containing the HA and NA genes (or both) from A/Chicken/Guangdong/SS/94 (Ck/GD/SS/94), in a background of internal genes derived from Ck/SH/F/98. Inoculated chickens were kept in either direct or indirect contact with uninoculated chickens, and viral shedding and titers were monitored. The results showed that Ck/GD/SS/94 lacks the ability to be transmitted through indirect contact, while Ck/SH/F/98 could be transmitted indirectly. Recombinant virus (RF/SSHA), containing the internal genes of Ck/SH/F/98 and the HA gene of Ck/GD/SS/94, resulted in decreased viral titers in lung tissue as compared to the parental strain. Interestingly, substituting the NA gene, or both the NA and HA genes, of Ck/SH/F/98 with that of Ck/GD/SS/94 completely abolished the airborne transmission of the recombinant RF/SSNA and RF/SSHA/SSNA. In conclusion, Ck/SH/F/98 acquired the ability of airborne transmission and replicated with a higher efficiency in the respiratory tract of the chickens. Our data indicated that the NA gene of Ck/SH/F/98 can affect virus replication and, therefore, indirectly affect the transmission for the gene constellations of these viruses.