School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada.
Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Saint-Hyacinthe, QC, Canada.
Sci Rep. 2019 Nov 13;9(1):16652. doi: 10.1038/s41598-019-50858-x.
In eastern North America, including Canada, Lyme disease is caused by Borrelia burgdorferi sensu stricto and transmitted to humans by the blacklegged tick, Ixodes scapularis. The last decade has seen a growing incidence of Lyme disease in Canada, following the northward range expansion of I. scapularis tick populations from endemic areas in eastern United States. This may be attributable to movement of the many hosts that they parasitize, including songbirds, deer and small mammals. In this study, we wanted to test the effect of spatial, temporal and ecological variables, on blacklegged tick density and infection rates, near the northern limit of their distribution in Ontario and Quebec, Canada. We found an effect of both proportion of forested areas and distance to roads, on density of I. scapularis ticks and prevalence of infection by B. burgdorferi. We also found an effect of both sampling year and ordinal sampling data on prevalence of infection by B. burgdorferi. In six adjacent sites showing evidence of reproducing I. scapularis populations, we found that forest composition and structure influenced density of I. scapularis ticks. Our results suggest that blacklegged tick density and infection rate in Canada may be influenced by a variety of factors.
在北美洲东部，包括加拿大，莱姆病是由伯氏疏螺旋体严格意义上引起的，并通过黑腿蜱，即肩突硬蜱传播给人类。在过去的十年中，随着肩突硬蜱种群从美国东部的流行地区向北扩展，加拿大莱姆病的发病率不断上升。这可能归因于许多宿主的迁徙，包括鸣禽、鹿和小型哺乳动物。在这项研究中，我们想测试空间、时间和生态变量对加拿大安大略省和魁北克省分布北端附近黑腿蜱密度和感染率的影响。我们发现，森林面积的比例和与道路的距离都对肩突硬蜱的密度和伯氏疏螺旋体的感染率有影响。我们还发现，采样年份和顺序采样数据对伯氏疏螺旋体的感染率都有影响。在六个相邻的显示出肩突硬蜱种群繁殖迹象的地点，我们发现森林组成和结构影响了肩突硬蜱的密度。我们的结果表明，加拿大黑腿蜱的密度和感染率可能受到多种因素的影响。
