Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
Ecology and Evolutionary Biology Department, Princeton University, Princeton, New Jersey.
Mol Ecol. 2019 May;28(9):2192-2205. doi: 10.1111/mec.15061. Epub 2019 May 10.
The role of wildlife in the persistence and spread of livestock diseases is difficult to quantify and control. These difficulties are exacerbated when several wildlife species are potentially involved. Bovine tuberculosis (bTB), caused by Mycobacterium bovis, has experienced an ecological shift in Michigan, with spillover from cattle leading to an endemically infected white-tailed deer (deer) population. It has potentially substantial implications for the health and well-being of both wildlife and livestock and incurs a significant economic cost to industry and government. Deer are known to act as a reservoir of infection, with evidence of M. bovis transmission to sympatric elk and cattle populations. However, the role of elk in the circulation of M. bovis is uncertain; they are few in number, but range further than deer, so may enable long distance spread. Combining Whole Genome Sequences (WGS) for M. bovis isolates from exceptionally well-observed populations of elk, deer and cattle with spatiotemporal locations, we use spatial and Bayesian phylogenetic analyses to show strong spatiotemporal admixture of M. bovis isolates. Clustering of bTB in elk and cattle suggests either intraspecies transmission within the two populations, or exposure to a common source. However, there is no support for significant pathogen transfer amongst elk and cattle, and our data are in accordance with existing evidence that interspecies transmission in Michigan is likely only maintained by deer. This study demonstrates the value of whole genome population studies of M. bovis transmission at the wildlife-livestock interface, providing insights into bTB management in an endemic system.
野生动物在维持和传播家畜疾病方面的作用难以量化和控制。当涉及多种野生动物物种时，这些困难会加剧。由牛分枝杆菌（Mycobacterium bovis）引起的牛结核病（bTB）在密歇根州经历了生态转变，牛的溢出导致了地方性感染的白尾鹿（deer）种群。这对野生动物和家畜的健康和福祉都有潜在的重大影响，并给行业和政府带来了巨大的经济成本。已知 deer 是感染的储库，有证据表明 M. bovis 传播给了同域的麋鹿和牛群。然而，elk 在 M. bovis 循环中的作用尚不确定；它们数量较少，但分布范围比 deer 更远，因此可能会导致远距离传播。我们结合了从 elk、deer 和 cattle 的异常观察种群中获得的牛分枝杆菌分离株的全基因组序列（WGS）以及时空位置，使用空间和贝叶斯系统发育分析来表明 M. bovis 分离株的强烈时空混合。elk 和 cattle 中的 bTB 聚类表明，两种种群内的种内传播，或暴露于共同来源。然而，没有证据表明 elk 和 cattle 之间存在重大病原体转移，并且我们的数据与现有的证据一致，即在密歇根州，种间传播很可能仅由 deer 维持。本研究展示了在野生动物-家畜界面进行 M. bovis 传播全基因组种群研究的价值，为地方性系统中的 bTB 管理提供了见解。
