The occurrence of Borrelia garinii in seabird ticks, Ixodes uriae, associated with different species of colonial seabirds has been studied since the early 1990s. Research on the population structure of this bacterium in ticks from seabird colonies in the northeastern Atlantic Ocean has revealed admixture between marine and terrestrial tick populations. We studied B. garinii genetic diversity and population structure in I. uriae collected from seabird colonies in the northwestern Atlantic Ocean, in Newfoundland and Labrador, Canada. We applied a multi-locus sequence typing (MLST) scheme to B. garinii found in ticks from four species of seabirds. The B. garinii strains found in this seabird colony ecosystem were diverse. Some were very similar to strains from Asia and Europe, including some obtained from human clinical samples, while others formed a divergent group specific to this region of the Atlantic Ocean. Our findings highlight the genetic complexity of B. garinii circulating in seabird ticks and their avian hosts but also demonstrate surprisingly close connections between B. garinii in this ecosystem and terrestrial sources in Eurasia. Genetic similarities among B. garinii from seabird ticks and humans indicate the possibility that B. garinii circulating within seabird tick-avian host transmission cycles could directly, or indirectly via connectivity with terrestrial transmission cycles, have consequences for human health.

自1990年代初以来，已经研究了与不同种类的殖民海鸟有关的海鸟壁虱（Ixodes uriae）中的疏螺旋体（Borrelia garinii）的发生。对东北大西洋海鸟殖民地tick中这种细菌的种群结构的研究表明，海洋和陆生tick种群之间存在混杂。我们研究了从西北大西洋，加拿大纽芬兰和拉布拉多的海鸟殖民地收集到的小肠弯曲杆菌的B. garinii遗传多样性和种群结构。我们对在四种海鸟的tick中发现的B. garinii应用了多基因座序列分型（MLST）方案。该B. garinii在这个海鸟殖民地生态系统中发现的菌株多种多样。一些与来自亚洲和欧洲的菌株非常相似，包括一些从人类临床样品中获得的菌株，而另一些则形成了一个特定于大西洋这一地区的分歧群体。我们的发现凸显了在海鸟壁虱及其鸟类寄主中循环的加倍芽孢杆菌的遗传复杂性，而且还证明了该生态系统中的加倍芽孢杆菌与欧亚大陆的陆源之间的紧密联系。海鸟tick和人之间的加里氏芽孢杆菌之间的遗传相似性表明了加里氏芽孢杆菌的可能性 在海鸟tick禽宿主传播周期中传播可能直接或通过与陆地传播周期的联系而间接地对人类健康产生影响。