One Health Institute, School of Veterinary Medicine, University of California Davis, One Shields Ave., Davis, California, 95616, USA.
Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.
Sci Rep. 2018 Apr 17;8(1):6088. doi: 10.1038/s41598-018-24133-4.
In temperate climates, transmission of West Nile virus (WNV) is detectable rarely during the coldest months (late fall through early spring), yet the virus has reappeared consistently during the next warm season. Several mechanisms may contribute to WNV persistence through winter, including bird-to-bird transmission among highly viremic species. Here we consider whether, under realistic scenarios supported by field and laboratory evidence, a winter bird community could sustain WNV through the winter in the absence of mosquitoes. With this purpose we constructed a deterministic model for a community of susceptible birds consisting of communally roosting crows, raptors and other birds. We simulated WNV introduction and subsequent transmission dynamics during the winter under realistic initial conditions and model parameterizations, including plausible contact rates for roosting crows. Model results were used to determine whether the bird community could yield realistic outbreaks that would result in WNV infectious individuals at the end of the winter, which would set up the potential for onward horizontal transmission into summer. Our findings strongly suggest that winter crow roosts could allow for WNV persistence through the winter, and our model results provide synthesis to explain inconclusive results from field studies on WNV overwintering in crow roosts.
在温带气候中，西尼罗河病毒 (WNV) 的传播在最冷的几个月（深秋至早春）很少被检测到，但在下一个温暖季节，该病毒却持续出现。有几种机制可能有助于 WNV 在冬季持续存在，包括在高病毒血症物种之间的鸟类间传播。在这里，我们考虑在野外和实验室证据支持的现实情况下，一个冬季鸟类群落是否可以在没有蚊子的情况下维持 WNV 度过冬季。为此，我们构建了一个由群居乌鸦、猛禽和其他鸟类组成的易感染鸟类群落的确定性模型。我们根据现实的初始条件和模型参数化模拟了冬季WNV 的引入和随后的传播动态，包括对乌鸦栖息的合理接触率。模型结果用于确定鸟类群落是否可以产生现实的爆发，从而导致冬季末的 WNV 感染个体，这将为夏季的水平传播创造潜力。我们的研究结果强烈表明，冬季乌鸦栖息地可以使 WNV 在冬季持续存在，我们的模型结果提供了综合解释，以解释在乌鸦栖息地越冬的 WNV 野外研究中不明确的结果。
