Department of Environmental Science and Technology, University of Maryland, College Park, Maryland, USA.
Department of Biology, Frostburg State University, Frostburg, Maryland, USA.
Ecol Appl. 2023 Oct;33(7):e2906. doi: 10.1002/eap.2906. Epub 2023 Aug 14.
Influenza A viruses in wild birds pose threats to the poultry industry, wild birds, and human health under certain conditions. Of particular importance are wild waterfowl, which are the primary reservoir of low-pathogenicity influenza viruses that ultimately cause high-pathogenicity outbreaks in poultry farms. Despite much work on the drivers of influenza A virus prevalence, the underlying viral subtype dynamics are still mostly unexplored. Nevertheless, understanding these dynamics, particularly for the agriculturally significant H5 and H7 subtypes, is important for mitigating the risk of outbreaks in domestic poultry farms. Here, using an expansive surveillance database, we take a large-scale look at the spatial, temporal, and taxonomic drivers in the prevalence of these two subtypes among influenza A-positive wild waterfowl. We document spatiotemporal trends that are consistent with past work, particularly an uptick in H5 viruses in late autumn and H7 viruses in spring. Interestingly, despite large species differences in temporal trends in overall influenza A virus prevalence, we document only modest differences in the relative abundance of these two subtypes and little, if any, temporal differences among species. As such, it appears that differences in species' phenology, physiology, and behaviors that influence overall susceptibility to influenza A viruses play a much lesser role in relative susceptibility to different subtypes. Instead, species are likely to freely pass viruses among each other regardless of subtype. Importantly, despite the similarities among species documented here, individual species still may play important roles in moving viruses across large geographic areas or sustaining local outbreaks through their different migratory behaviors.
在某些条件下，野生鸟类中的甲型流感病毒会对家禽业、野生鸟类和人类健康构成威胁。特别重要的是野生水禽，它们是低致病性流感病毒的主要宿主，而这些病毒最终会导致家禽养殖场发生高致病性疫情。尽管人们已经对甲型流感病毒流行的驱动因素进行了大量研究，但病毒亚型的潜在动态仍在很大程度上尚未得到探索。然而，了解这些动态，特别是对于农业上重要的 H5 和 H7 亚型，对于减轻家禽养殖场爆发的风险非常重要。在这里，我们利用一个广泛的监测数据库，大规模研究了这两种亚型在甲型流感阳性野生水禽中流行的空间、时间和分类学驱动因素。我们记录了与过去工作一致的时空趋势，特别是 H5 病毒在深秋和 H7 病毒在春季的增加。有趣的是，尽管在总体甲型流感病毒流行的时间趋势方面存在很大的物种差异，但我们仅记录了这两种亚型的相对丰度的适度差异，并且在物种之间几乎没有时间差异。因此，似乎物种的物候、生理和行为差异对总体易感性影响不大，而对不同亚型的相对易感性影响较小。相反，物种之间可能会自由地传播病毒，而不管亚型如何。重要的是，尽管这里记录了物种之间的相似之处，但个别物种仍然可能通过不同的迁徙行为在大地理区域传播病毒或维持当地疫情方面发挥重要作用。
