Zoological Museum, Biodiversity Unit, University of Turku, Turku, Finland.
Department of Forest Sciences, University of Helsinki, Helsinki, Finland.
Zoonoses Public Health. 2020 Nov;67(7):823-839. doi: 10.1111/zph.12767. Epub 2020 Sep 24.
Most tick-related studies in Europe have been conducted in nonurban areas, but ticks and tick-borne pathogens also occur in urban green spaces. From a public health perspective, risks regarding tick-borne infections should be studied in these urban areas, where contacts between infected ticks and humans may be more frequent than elsewhere, due to high human activity. We examined the risk of encountering an infected tick in urban green spaces in Helsinki, Finland. We collected ticks at nine sites throughout Helsinki, recorded the prevalence of several pathogens and identified areas with a high potential for contacts between infected ticks and humans. Moreover, we explored the relationship between the density of Borrelia burgdorferi sensu lato-infected ticks and locally diagnosed cases of borreliosis and compared the potential for human-tick encounters in Helsinki to those in nonurban areas in south-western Finland. During 34.8 km of cloth dragging, 2,417 Ixodes ricinus were caught (402 adults, 1,399 nymphs and 616 larvae). From analysed nymphs, we found 11 distinct tick-borne pathogens, with 31.5% of nymphs carrying at least one pathogen. Tick activity was highest in August and September, leading to the density of nymphs infected with B. burgdorferi s.l., and concurrently infection risk, to also be highest during this time. Nymph densities varied between the sampling sites, with obvious implications to spatial variation in infection risk. While ticks and tick-borne pathogens were found in both Helsinki and nonurban areas in south-western Finland, the estimates of human activity were generally higher in urban green spaces, leading to a higher potential for human-tick contacts therein. The presence of ticks and tick-borne pathogens and high local human activity in urban green spaces suggest that they form potential foci regarding the acquisition of tick-borne infections. Risk areas within cities should be identified and knowledge regarding urban ticks increased.
大多数在欧洲进行的与蜱虫相关的研究都是在非城市地区进行的，但蜱虫和蜱传病原体也存在于城市绿地中。从公共卫生的角度来看，由于人类活动频繁，这些城市地区感染蜱虫和人类之间的接触可能比其他地方更为频繁，因此应该研究蜱传感染的风险。我们研究了在芬兰赫尔辛基的城市绿地中遇到感染蜱虫的风险。我们在赫尔辛基的九个地点采集了蜱虫，记录了几种病原体的流行情况，并确定了感染蜱虫与人之间具有高接触潜力的区域。此外，我们还探讨了感染伯氏疏螺旋体的蜱虫密度与当地诊断的莱姆病病例之间的关系，并将赫尔辛基的人与蜱虫接触的可能性与芬兰西南部非城市地区进行了比较。在 34.8 公里的布拖曳过程中，共捕获了 2417 只硬蜱（402 只成虫、1399 只若虫和 616 只幼虫）。从分析的若虫中，我们发现了 11 种不同的蜱传病原体，其中 31.5%的若虫携带至少一种病原体。蜱虫的活动高峰期在 8 月和 9 月，导致感染伯氏疏螺旋体的若虫密度以及同时的感染风险也在这段时间内最高。采样点之间的若虫密度存在差异，这对感染风险的空间变化有明显的影响。虽然赫尔辛基和芬兰西南部的非城市地区都发现了蜱虫和蜱传病原体，但城市绿地中的人类活动估计通常更高，从而导致人与蜱虫接触的潜在可能性更高。城市绿地中存在蜱虫和蜱传病原体以及当地人类活动的高频率表明，这些地区可能成为蜱传感染的潜在焦点。应该确定城市内的风险区域，并增加对城市蜱虫的了解。
