Korea Institute of Ornithology, Kyung Hee University, Seoul, Republic of Korea.
Department of Biology, Kyung Hee University, Seoul, Republic of Korea.
Transbound Emerg Dis. 2022 Sep;69(5):e3128-e3140. doi: 10.1111/tbed.14669. Epub 2022 Aug 3.
Previous studies and efforts to prevent and manage avian influenza (AI) outbreaks have mainly focused on the wintering season. However, outbreaks of AI have been reported in the summer, including the breeding season of waterfowl. Additionally, the spatial distribution of waterfowl can easily change during the annual cycle due to their life-cycle traits and the presence of both migrants and residents in the population. Thus, we assessed the spatiotemporal variation in AI exposure risk in poultry due to spatial distribution changes in three duck species included in both major residents and wintering migrants in South Korea, the mandarin, mallard and spot-billed duck, during wintering (October-March), breeding (April-June) and whole annual seasons. To estimate seasonal ecological niche variations among the three duck species, we applied pairwise ecological niche analysis using the Pianka index. Subsequently, seasonal distribution models were projected by overlaying the monthly ranges estimated by the maximum entropy model. Finally, we overlaid each seasonal distribution range onto a poultry distribution map of South Korea. We found that the mandarin had less niche overlap with the mallard and spot-billed duck during the wintering season than during the breeding season, whereas the mallard had less niche overlap with the mandarin and spot-billed duck during the breeding season than during the wintering season. Breeding and annual distribution ranges of the mandarin and spot-billed duck, but not the mallard, were similar or even wider than their wintering ranges. Similarly, the mandarin and spot-billed duck showed more extensive overlap proportions between poultry and their distributional ranges during both the breeding and annual seasons than during the wintering season. These results suggest that potential AI exposure in poultry can occur more widely in the summer than in winter, depending on sympatry with the host duck species. Future studies considering the population density and variable pathogenicity of AI are required.
先前的研究和预防管理禽流感（Avian Influenza，AI）爆发的努力主要集中在冬季。然而，夏季也有 AI 爆发的报告，包括水禽的繁殖季节。此外，由于水禽的生命周期特征以及种群中存在候鸟和留鸟，它们的种群空间分布在年度周期中很容易发生变化。因此，我们评估了由于韩国三种主要留鸟和冬候鸟的水禽空间分布变化而导致家禽接触 AI 风险的时空变化，这三种水禽分别为麻鸭、绿头鸭和斑嘴鸭，包括冬季（10 月至 3 月）、繁殖季（4 月至 6 月）和全年。为了估计这三种鸭在冬季和繁殖季的生态位差异，我们应用 Pianka 指数进行了成对的生态位分析。随后，通过覆盖最大熵模型估计的每月范围，对季节性分布模型进行了预测。最后，我们将每个季节性分布范围叠加到韩国家禽分布图上。结果发现，麻鸭在冬季的生态位重叠程度低于繁殖季，而绿头鸭在繁殖季的生态位重叠程度低于冬季。麻鸭和斑嘴鸭的繁殖和全年分布范围与冬季相似或甚至更宽，而绿头鸭则不然。同样，麻鸭和斑嘴鸭在繁殖季和全年的家禽分布范围与宿主鸭类的重叠比例比冬季更为广泛。这些结果表明，家禽接触 AI 的潜在风险在夏季可能比冬季更为广泛，具体取决于与宿主鸭类的同域分布。需要考虑 AI 种群密度和变异性的未来研究。
