Rahman Ishraq, Erdelyan Cassidy N G, Signore Anthony V, Ayilara Ifeoluwa, Wight Jordan, Jones Megan E B, Sullivan Daniel S, Lung Oliver, Hisanaga Tamiko, Wilhelm Sabina I, Cunningham Joshua T, Ward Christopher R E, Bosch Johanna, Robertson Gregory J, Gosse Karen, Baker Meghan, Dawe Beverly, Lair Stéphane, Provencher Jennifer F, Hargan Kathryn E, Berhane Yohannes, Lang Andrew S
Department of Biology, Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada.
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB R3E 3M4, Canada.
Virus Evol. 2024 Dec 17;10(1):veae111. doi: 10.1093/ve/veae111. eCollection 2024.
Wild birds are important hosts of influenza A viruses (IAVs) and play an important role in their ecology. The emergence of the A/goose/Guangdong/1/1996 H5N1 (Gs/GD) lineage marked a shift in IAV ecology, leading to recurrent outbreaks and mortality in wild birds from 2002 onwards. This lineage has evolved and diversified over time, with a recent important derivative being the 2.3.4.4b sub-lineage, which has caused significant mortality events in wild bird populations. An H5N1 clade 2.3.4.4b virus was transmitted into North America from Eurasia in 2021, with the first detection being in Newfoundland and Labrador in Atlantic Canada, and this virus and its reassortants then spread broadly throughout North America and beyond. Following the first 2021 detection, there have been three additional known incursions of Eurasian-origin strains into Atlantic Canada, a second H5N1 strain in 2022 and two H5N5 strains in 2023. In this study, we document a fifth incursion in Atlantic Canada that occurred in 2023 by another H5N5 strain. This strain spread throughout Atlantic Canada and into Quebec, infecting numerous species of wild birds and mammals. Genomic analysis revealed mammalian-adaptive mutations in some of the detected viruses (PB2-E627K and PB2-D701N) and mutations in the hemagglutinin (HA) and neuraminidase (NA) genes that are associated with enhanced viral fitness and avian transmission capabilities. Our findings indicate that this virus is continuing to circulate in wildlife, and confirms Atlantic Canada is an important North American entry point for Eurasian IAVs. Continued surveillance and genomic analysis of IAVs detected in the region is crucial to monitor the evolution of these viruses and assess potential risks to wildlife and public health.
野生鸟类是甲型流感病毒（IAVs）的重要宿主，在其生态中发挥着重要作用。A/鹅/广东/1/1996 H5N1（Gs/GD）谱系的出现标志着IAV生态的转变，导致自2002年起野生鸟类反复爆发疫情并出现死亡。随着时间的推移，这一谱系不断进化和多样化，近期一个重要的衍生谱系是2.3.4.4b亚谱系，它在野生鸟类种群中引发了重大死亡事件。一种H5N1 2.3.4.4b分支病毒于2021年从欧亚大陆传入北美，首次检测到是在加拿大大西洋地区的纽芬兰和拉布拉多，随后这种病毒及其重配病毒广泛传播至北美及其他地区。在2021年首次检测到之后，又有三次已知的欧亚起源毒株侵入加拿大大西洋地区，2022年出现了第二种H5N1毒株，2023年出现了两种H5N5毒株。在本研究中，我们记录了2023年在加拿大大西洋地区发生的第五次侵入事件，涉及另一种H5N5毒株。该毒株传播至加拿大大西洋地区全境并进入魁北克，感染了众多野生鸟类和哺乳动物物种。基因组分析揭示，在一些检测到的病毒中存在适应哺乳动物的突变（PB2-E627K和PB2-D701N）以及血凝素（HA）和神经氨酸酶（NA）基因中的突变，这些突变与增强的病毒适应性和禽类传播能力相关。我们的研究结果表明，这种病毒仍在野生动物中传播，并证实加拿大大西洋地区是欧亚IAV进入北美的一个重要入口点。对该地区检测到的IAV持续进行监测和基因组分析对于监测这些病毒的进化以及评估对野生动物和公共卫生的潜在风险至关重要。
