Ecosystem Interactions Underlie the Spread of Avian Influenza A Viruses with Pandemic Potential

Despite evidence for avian influenza A virus (AIV) transmission between wild and domestic ecosystems, the roles of bird migration and poultry trade in the spread of viruses remain enigmatic. In this study, we integrate ecosystem interactions into a phylogeographic model to assess the contribution of wild and domestic hosts to AIV distribution and persistence. Analysis of globally sampled AIV datasets shows frequent two-way transmission between wild and domestic ecosystems. In general, viral flow from domestic to wild bird populations was restricted to within a geographic region. In contrast, spillover from wild to domestic populations occurred both within and between regions. Wild birds mediated long-distance dispersal at intercontinental scales whereas viral spread among poultry populations was a major driver of regional spread. Viral spread between poultry flocks frequently originated from persistent lineages circulating in regions of intensive poultry production. Our analysis of long-term surveillance data demonstrates that meaningful insights can be inferred from integrating ecosystem into phylogeographic reconstructions that may be consequential for pandemic preparedness and livestock protection.尽管已有证据证实甲型禽流感病毒（avian influenza A virus, AIV）可在野生与家养生态系统间发生传播，但候鸟迁徙与家禽贸易在病毒传播过程中所扮演的具体角色仍不明朗。本研究将生态系统交互作用整合至系统发育地理学模型中，以此评估野生与家养宿主对AIV的分布及持续存续的贡献。对全球采样的AIV数据集进行分析后发现，野生与家养生态系统间存在频繁的双向病毒传播。总体而言，从家养禽类种群向野生鸟类种群的病毒传播仅局限于单一地理区域内部。与之相对，从野生鸟类种群向家养禽类种群的病毒溢出事件则同时存在于单个地理区域内部以及不同区域之间。野生鸟类介导了跨洲际尺度的长距离病毒扩散，而家禽种群间的病毒传播则是区域内病毒传播的主要驱动因素。家禽养殖群体间的病毒传播往往源自于在集约化家禽养殖区域持续循环流行的病毒谱系。我们对长期监测数据的分析表明，将生态系统维度纳入系统发育地理学重建分析，可获得具有重要价值的研究结论，这对于大流行防控与畜禽保护工作或具有深远影响。