US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA.
US Geological Survey, California Water Science Center, 6000 J Street, Placer Hall, Sacramento, CA 95819, USA.
Proc Biol Sci. 2020 Sep 9;287(1934):20201680. doi: 10.1098/rspb.2020.1680.
In this investigation, we used a combination of field- and laboratory-based approaches to assess if influenza A viruses (IAVs) shed by ducks could remain viable for extended periods in surface water within three wetland complexes of North America. In a field experiment, replicate filtered surface water samples inoculated with duck swabs were tested for IAVs upon collection and again after an overwintering period of approximately 6-7 months. Numerous IAVs were molecularly detected and isolated from these samples, including replicates maintained at wetland field sites in Alaska and Minnesota for 181-229 days. In a parallel laboratory experiment, we attempted to culture IAVs from filtered surface water samples inoculated with duck swabs from Minnesota each month during September 2018-April 2019 and found monthly declines in viral viability. In an experimental challenge study, we found that IAVs maintained in filtered surface water within wetlands of Alaska and Minnesota for 214 and 226 days, respectively, were infectious in a mallard model. Collectively, our results support surface waters of northern wetlands as a biologically important medium in which IAVs may be both transmitted and maintained, potentially serving as an environmental reservoir for infectious IAVs during the overwintering period of migratory birds.
在这项研究中，我们采用了现场和实验室相结合的方法，评估了鸭子排出的甲型流感病毒（IAV）是否可以在北美的三个湿地复合体的地表水中长期保持存活。在一项野外实验中，用鸭子拭子接种的重复过滤的地表水样本在采集后和经过大约 6-7 个月的越冬期后进行了 IAV 检测。从这些样本中检测到并分离出了大量的 IAV，包括在阿拉斯加和明尼苏达州的湿地现场保存了 181-229 天的样本。在一项平行的实验室实验中，我们试图从 2018 年 9 月至 2019 年 4 月期间每月用明尼苏达州鸭子拭子接种过滤的地表水样本进行 IAV 培养，但发现病毒的生存力每月都在下降。在一项实验性挑战研究中，我们发现，在阿拉斯加和明尼苏达州的湿地中分别保存了 214 天和 226 天的 IAV 在过滤的地表水仍具有感染性，能使野鸭发病。总的来说，我们的研究结果支持北方湿地的地表水是 IAV 传播和维持的重要生物媒介，可能是候鸟越冬期间传染性 IAV 的环境储库。
