Data from: Population structure of two rabies hosts relative to the known distribution of rabies virus variants in Alaska

For pathogens that infect multiple species the distinction between reservoir hosts and spillover hosts is often difficult. In Alaska, three variants of the arctic rabies virus exist with distinct spatial distributions. We test the hypothesis that rabies virus variant distribution corresponds to the population structure of the primary rabies hosts in Alaska, arctic foxes (Vulpes lagopus) and red foxes (V. vulpes) in order to possibly distinguish reservoir and spill over hosts. We used mitochondrial DNA (mtDNA) sequence and nine microsatellites to assess population structure in those two species. mtDNA structure did not correspond to rabies virus variant structure in either species. Microsatellite analyses gave varying results. Bayesian clustering found 2 groups of arctic foxes in the coastal tundra region, but for red foxes it identified tundra and boreal types. Spatial Bayesian clustering and spatial principal components analysis identified 3 and 4 groups of arctic foxes, respectively, closely matching the distribution of rabies virus variants in the state. Red foxes, conversely, showed eight clusters comprising 2 regions (boreal and tundra) with much admixture. These results run contrary to previous beliefs that arctic fox show no fine-scale spatial population structure. While we cannot rule out that the red fox is part of the maintenance host community for rabies in Alaska, the distribution of virus variants appears to be driven primarily by the artic fox Therefore we show that host population genetics can be utilized to distinguish between maintenance and spillover hosts when used in conjunction with other approaches.

对于可感染多种宿主的病原体而言，区分储存宿主（reservoir host）与溢出宿主（spillover host）往往颇具难度。在阿拉斯加州，存在三种空间分布特征迥异的北极狂犬病毒变异株。本研究旨在验证下述假说：阿拉斯加州狂犬病毒变异株的分布格局，与该地区狂犬病毒的主要宿主——北极狐（Vulpes lagopus）及赤狐（V. vulpes）的种群结构相匹配，以此尝试区分储存宿主与溢出宿主。
我们通过线粒体DNA（mitochondrial DNA, mtDNA）序列与9个微卫星标记，对这两种狐类的种群结构进行评估。结果显示，两种狐类的线粒体DNA种群结构均未与狂犬病毒变异株的分布格局形成对应。微卫星分析则得到了不尽一致的结果：贝叶斯聚类分析显示，沿海苔原区域的北极狐可划分为2个种群；而赤狐则被划分为苔原型与北方林型两类。空间贝叶斯聚类与空间主成分分析分别识别出3组和4组北极狐种群，其分布与阿拉斯加州内狂犬病毒变异株的分布高度吻合。与之相反，赤狐被划分为8个聚类群，仅覆盖北方林与苔原2个区域且存在大量遗传混合。
本研究结果与此前认为北极狐不存在精细空间种群结构的观点相悖。尽管我们无法排除赤狐参与维持阿拉斯加州狂犬病毒宿主群落的可能性，但病毒变异株的分布格局似乎主要由北极狐所驱动。综上，本研究表明，若结合其他研究手段，宿主种群遗传学方法可用于区分狂犬病毒的维持宿主与溢出宿主。