Clow Katie M, Ogden Nicholas H, Lindsay L Robbin, Michel Pascal, Pearl David L, Jardine Claire M
Department of Pathobiology, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada.
National Microbiology Laboratory, Public Health Agency of Canada, 3200 Sicotte, C.P. 5000, Saint-Hyacinthe, Quebec, J2S 7C6, Canada.
Ticks Tick Borne Dis. 2017 Jun;8(4):554-563. doi: 10.1016/j.ttbdis.2017.03.003. Epub 2017 Mar 21.
In northeastern North America, the blacklegged tick, Ixodes scapularis, is the vector of numerous tick-borne pathogens, including the agent of Lyme disease, Borrelia burgdorferi sensu stricto. Since 1990, there has been a rapid spread of I. scapularis northward into the province of Ontario, Canada. Climate change has been implicated as one of the driving factors for the spread of this vector. Other ecological factors also influence survival of I. scapularis populations and may facilitate invasion. The objective of this study was to identify local abiotic and biotic factors of significance for the invasion of I. scapularis in Ontario. The presence of ticks was determined by drag sampling at 154 sites in southern, eastern and central Ontario from May to October in 2014 and 2015. At each site, data on site aspect, forest cover, understory density and composition, soil moisture and composition, and the depth of litter layer were collected. Cumulative degree days above zero °C, total precipitation and elevation were attributed to each site using a geographic information system. A mixed multi-variable logistic regression model was created to assess the impact of the ecological factors on the presence of I. scapularis. In total, I. scapularis was found at 29 sites (18.8%) across the study area. The density of the understory, the presence of shrubs and the interaction of these two ecological factors were statistically significant, as well as longitude and cumulative degree days above zero. Our findings illustrate that local ecological factors are of importance for the invasion of I. scapularis into Ontario, and may be used to enhance local public health interventions and current predictive models and risk maps for I. scapularis.
在北美东北部，黑脚硬蜱（Ixodes scapularis）是多种蜱传病原体的传播媒介，包括莱姆病病原体伯氏疏螺旋体（Borrelia burgdorferi sensu stricto）。自1990年以来，黑脚硬蜱迅速向北扩散至加拿大安大略省。气候变化被认为是该传播媒介扩散的驱动因素之一。其他生态因素也影响黑脚硬蜱种群的生存，并可能促进其入侵。本研究的目的是确定对安大略省黑脚硬蜱入侵具有重要意义的当地非生物和生物因素。通过在2014年和2015年5月至10月期间对安大略省南部、东部和中部的154个地点进行拖网采样来确定蜱的存在情况。在每个地点，收集了关于地点朝向、森林覆盖、林下植被密度和组成、土壤湿度和组成以及枯枝落叶层深度的数据。利用地理信息系统将高于0°C的累积度日、总降水量和海拔高度归因于每个地点。创建了一个混合多变量逻辑回归模型来评估生态因素对黑脚硬蜱存在的影响。在整个研究区域内，共在29个地点（18.8%）发现了黑脚硬蜱。林下植被密度、灌木的存在以及这两个生态因素的相互作用具有统计学意义，经度和高于0°C的累积度日也具有统计学意义。我们的研究结果表明，当地生态因素对黑脚硬蜱入侵安大略省具有重要意义，可用于加强当地公共卫生干预措施以及当前针对黑脚硬蜱的预测模型和风险地图。
