Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
Department of Biology, McGill University, Montréal, Quebec, Canada.
Zoonoses Public Health. 2024 Feb;71(1):18-33. doi: 10.1111/zph.13093. Epub 2023 Nov 13.
Starting in the early 20th century, ticks and their pathogens have been detected during surveillance efforts in Canada. Since then, the geographic spread of tick vectors and tick-borne pathogens has steadily increased in Canada with the establishment of tick and host populations. Sentinel surveillance in Canada primarily focuses on Ixodes scapularis, which is the main vector of Borrelia burgdorferi, the bacterium causing Lyme disease. Other tick-borne pathogens, such as Anaplasma, Babesia, and Rickettsia species, have lower prevalence in Canada, but they are emerging or re-emerging in tick and host populations.
AIMS/MATERIALS & METHODS: Here, we assessed the historical associations between tick vectors, hosts and pathogens and identified spatiotemporal clusters of pathogen presence in ticks in Canada using data extracted from the literature.
Approximately one-third of ticks were infected with a pathogen, and these ticks were feeding primarily on bird and mammal hosts. B. burgdorferi was the most detected pathogen and I. scapularis harboured the greatest number of pathogens. We identified several spatial outliers of high pathogen presence in ticks in addition to five spatiotemporal clusters in southern Canada, all of which have long-established tick populations. Six spatiotemporal clusters of high pathogen presence in ticks were also identified based on surveillance method, with four clusters associated with passive surveillance and two clusters associated with active surveillance.
Our review represents the first systematic assessment of the literature that identifies historical associations and spatiotemporal changes in tick-host-pathogen disease systems in Canada over broad spatial and temporal scales.
As distinct spatiotemporal clusters were identified based on surveillance method, it is imperative that surveillance efforts employ standardized methods and data reporting to comprehensively assess the presence, spread and risk of tick-borne pathogens in tick and host populations.
早在 20 世纪初，在加拿大的监测工作中就发现了蜱虫及其病原体。从那时起，随着蜱虫和宿主种群的建立，蜱虫媒介和蜱传病原体在加拿大的地理分布稳步扩大。加拿大的哨点监测主要集中在Ixodes scapularis 上，它是引起莱姆病的细菌Borrelia burgdorferi 的主要媒介。其他蜱传病原体，如 Anaplasma、Babesia 和 Rickettsia 种类，在加拿大的流行率较低，但它们在蜱虫和宿主种群中正在出现或重新出现。
目的/材料和方法：在这里，我们评估了蜱虫媒介、宿主和病原体之间的历史关联，并使用从文献中提取的数据确定了加拿大蜱虫中病原体存在的时空聚类。
大约三分之一的蜱虫感染了一种病原体，这些蜱虫主要以鸟类和哺乳动物为食。B. burgdorferi 是最常见的病原体，I. scapularis 携带的病原体最多。除了在加拿大南部发现的五个时空聚类外，我们还确定了几个蜱虫中高病原体存在的空间异常值，所有这些都有长期存在的蜱虫种群。还根据监测方法确定了六个蜱虫中高病原体存在的时空聚类，其中四个聚类与被动监测有关，两个聚类与主动监测有关。
我们的综述代表了首次对文献进行的系统评估，该评估确定了加拿大在广泛的时空尺度上蜱-宿主-病原体疾病系统的历史关联和时空变化。
由于根据监测方法确定了不同的时空聚类，因此监测工作必须采用标准化方法和数据报告，以全面评估蜱虫和宿主种群中蜱传病原体的存在、传播和风险。
