Banet-Noach C, Perk S, Simanov L, Grebenyuk N, Rozenblut E, Pokamunski S, Pirak M, Tendler Y, Panshin A
Division of Avian and Aquatic Diseases, Kimron Veterinary Institute, P.O. Box 12, Beit Dagan 50250, Israel.
Avian Dis. 2007 Mar;51(1 Suppl):290-6. doi: 10.1637/7590-040206R1.1.
Since 2000, hundreds of H9N2 viruses have been isolated from all types of domestic birds. Although H9N2 is a low-pathogenicity virus, disease has been observed in all types of poultry in the field. Clinical signs ranged from very mild disease to high morbidity and mortality when the virus was associated with a secondary pathogen. Because of the wide range of the virus and the great losses it caused, initially a local vaccination program was implemented, but mass vaccination was quickly authorized. A local strain, isolated in 2002 was selected and is currently in use as an inactivated vaccine. An intensive operation is in progress to characterize the isolates. Several genes (hemagglutinin [HA], neuraminidase, nonstructural protein, nucleoprotein, and matrix) were sequenced, revealing three main groups: the first group included two isolates from 2000, the second group included isolates from 2001 to the beginning of 2003, and the third group included all isolates from 2003 to date. The differences between the second and third groups, in a part of the HA gene, ranged from 3.49% to 6.97% (average 4.57%) of the nucleotides. Similar differences were recorded in the other tested genes. These data could indicate the probable introduction of distinct progenitor viruses into the Israeli poultry population. Furthermore, sequencing of the HA protein of some Israeli isolates revealed the presence of L216 in the binding site; this finding was typical of the H9N2 viruses isolated from humans, which raises the possibility of an influence on host specificity and virulence.
自2000年以来，已从各类家禽中分离出数百株H9N2病毒。尽管H9N2是一种低致病性病毒，但在野外的各类家禽中均观察到疾病发生。临床症状从非常轻微的疾病到高发病率和死亡率不等，当该病毒与继发病原体相关联时。由于该病毒传播范围广且造成巨大损失，最初实施了局部疫苗接种计划，但很快就批准了大规模疫苗接种。2002年分离出的一株本地毒株被选中，目前用作灭活疫苗。正在进行一项深入的工作来鉴定这些分离株。对几个基因（血凝素[HA]、神经氨酸酶、非结构蛋白、核蛋白和基质）进行了测序，揭示了三个主要组：第一组包括2000年的两株分离株，第二组包括2001年至2003年初的分离株，第三组包括2003年至今的所有分离株。第二组和第三组之间在HA基因的一部分上的核苷酸差异范围为3.49%至6.97%（平均4.57%）。在其他测试基因中也记录到了类似的差异。这些数据可能表明不同的祖代病毒可能传入了以色列的家禽群体。此外，对一些以色列分离株的HA蛋白进行测序发现，其结合位点存在L216；这一发现是从人类分离出的H9N2病毒所特有的，这增加了对宿主特异性和毒力产生影响的可能性。
