H9N2 avian influenza viruses (AIV) has a worldwide geographic distribution and affects poultry of different types of production. H9N2 AIV was first reported in the Northeast of Algeria in April 2017, following an outbreak associated with high mortality, in broiler flocks. In the present study, we report full-length genome sequences of AIV H9N2, and the detailed phylogeny and molecular genetic analyses. Ten AIV H9N2 strains, collected in broiler flocks, were amplified in 9-day-old embryonated specific pathogen free (SPF) chicken eggs. Their full-length genomes were successfully sequenced and phylogenetic and molecular characterizations were conducted. Phylogenetic analysis showed that the isolates were monophyletic, grouped within the G-1 lineage and were very close to Moroccan and Algerian strains identified in 2016 and 2017, respectively. The low pathogenicity of the strains was confirmed by the sequence motif (335RSSR/GLF341) at the hemagglutinin (HA) cleavage site. An exclusive substitution (T197A) that had not been previously reported for H9N2 viruses; but, conserved in some pandemic H1N1 viruses, was observed. When compared to the G1-like H9N2 prototype, the studied strains showed one less glycosylation site in HA, but 2–3 additional ones in the stalk of the neuraminidase (NA). The HA protein harbored the substitution 234 L, suggesting binding preference to human-like receptors. The NA protein harbored S372A and R403W substitutions, previously detected in H9N2 from Asia and the Middle East, and especially in H2N2 and H3N2 strains that caused human pandemics. Different molecular markers associated with virulence and mammalian infections have been detected in the viral internal proteins. The matrix M2 protein possessed the S31N substitution associated with drug resistance. The non-structural 1 (NS1) protein showed the “GSEV” PDZ ligand (PL) C-terminal motif and no 80–84 deletion. Characterized Algerian AIV isolates showed mutations that suggest increased zoonotic potential. Additional studies in animal models are required to investigate the pathogenicity of these H9N2 AIV strains. Monitoring their evolution in both migratory and domestic birds is crucial to prevent transmission to humans. Implementation of adequate biosecurity measures that limit the introduction and the propagation of AIV H9N2 in Algerian poultry farm is crucial.

中文翻译：

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在阿尔及利亚东北部分离的首批H9N2禽流感病毒的全长基因组序列。

H9N2禽流感病毒（AIV）具有全球地理分布，并影响不同类型生产的家禽。H9N2 AIV于2017年4月在阿尔及利亚东北部首次报告，当时爆发与高死亡率相关的肉鸡群。在本研究中，我们报告了AIV H9N2的全长基因组序列，以及详细的系统发育和分子遗传分析。在鸡群中收集的十个AIV H9N2菌株在9天大的无特定病原体（SPF）胚胎的鸡蛋中扩增。他们的全长基因组已成功测序，并进行了系统发育和分子表征。系统发育分析表明，分离株是单系的，归类于G-1谱系，分别与2016年和2017年鉴定的摩洛哥和阿尔及利亚菌株非常接近。血凝素（HA）切割位点的序列基序（335RSSR / GLF341）证实了该菌株的低致病性。以前没有报道过H9N2病毒的独家替代品（T197A）；但是，在某些大流行的H1N1病毒中却观察到了保守性。与类似G1的H9N2原型相比，所研究的菌株在HA中的糖基化位点少了一个，而在神经氨酸酶（NA）的茎中又增加了2-3个。HA蛋白具有取代234 L，表明对人样受体的结合偏好。NA蛋白带有S372A和R403W取代，先前在亚洲和中东的H9N2中，尤其是在引起人类大流行的H2N2和H3N2菌株中检测到。在病毒内部蛋白中已检测到与毒力和哺乳动物感染相关的不同分子标记。基质M2蛋白具有与耐药相关的S31N取代。非结构1（NS1）蛋白显示“ GSEV” PDZ配体（PL）C端基序，没有80-84缺失。表征的阿尔及利亚AIV分离物显示突变，表明人畜共患病潜力增加。需要在动物模型中进行其他研究以调查这些H9N2 AIV毒株的致病性。监测候鸟和家禽的进化对防止传播给人类至关重要。实施适当的生物安全措施以限制AIV H9N2在阿尔及利亚家禽农场的引进和繁殖至关重要。基质M2蛋白具有与耐药相关的S31N取代。非结构1（NS1）蛋白显示“ GSEV” PDZ配体（PL）C端基序，没有80-84缺失。表征的阿尔及利亚AIV分离物显示突变，表明人畜共患病潜力增加。需要在动物模型中进行其他研究以调查这些H9N2 AIV毒株的致病性。监测候鸟和家禽的进化对防止传播给人类至关重要。实施适当的生物安全措施以限制AIV H9N2在阿尔及利亚家禽农场的引进和繁殖至关重要。基质M2蛋白具有与耐药相关的S31N取代。非结构1（NS1）蛋白显示“ GSEV” PDZ配体（PL）C端基序，没有80-84缺失。表征的阿尔及利亚AIV分离物显示出提示增加人畜共患病潜力的突变。需要在动物模型中进行其他研究以调查这些H9N2 AIV毒株的致病性。监测候鸟和家禽的进化对防止传播给人类至关重要。实施适当的生物安全措施以限制AIV H9N2在阿尔及利亚家禽农场的引进和繁殖至关重要。表征的阿尔及利亚AIV分离物显示突变，表明人畜共患病潜力增加。需要在动物模型中进行其他研究以调查这些H9N2 AIV毒株的致病性。监测候鸟和家禽的进化对防止传播给人类至关重要。实施适当的生物安全措施以限制AIV H9N2在阿尔及利亚家禽农场的引进和繁殖至关重要。表征的阿尔及利亚AIV分离物显示突变，表明人畜共患病潜力增加。需要在动物模型中进行其他研究以调查这些H9N2 AIV毒株的致病性。监测候鸟和家禽的进化对防止传播给人类至关重要。实施适当的生物安全措施以限制AIV H9N2在阿尔及利亚家禽农场的引进和繁殖至关重要。