Eisen L, Eisen R J, Lane R S
Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA.
J Med Entomol. 2006 Mar;43(2):415-27. doi: 10.1603/0022-2585(2006)043[0415:gdpahs]2.0.co;2.
We used drag sampling to examine the geographical distribution patterns of ixodid ticks engaging in open (non-nidicolous) host-seeking behavior in dense woodland habitats of the climatically and ecologically diverse Mendocino County in north coastal California. The findings based on this sampling methodology reflect risk of human exposure to host-seeking ticks rather than the true distribution of the ticks. Drag sampling in 78 sites yielded 7,860 nymphal or adult Ixodes pacificus Cooley & Kohls, 220 Dermacentor occidentalis Marx, 150 Ixodes spinipalpis Hadwen & Nuttall, 15 Hemaphysalis leporispalustris (Packard), 12 Ixodes angustus Neumann, 12 Ixodes auritulus Neumann, and a single Dermacentor variabilis (Say). I. pacificus, which is the primary vector of the Lyme disease spirochete Borrelia burgdorferi to humans in California, occurred in all 78 sites examined. D. occidentalis, another tick species commonly biting humans in California, and H. leporispalustris typically were encountered in oak-associated woodlands in the central or eastern parts of the county. In contrast, three species of Ixodes ticks (I. angustus, I. auritulus, and I. spinipalpis) most commonly were found questing openly in woodlands with redwood present in the western part of the county. I. angustus and I. spinipalpis are occasional human biters and known experimental vectors of B. burgdorferi. Our study represents the first collection of large numbers of openly host-seeking I. spinipalpis ticks. Univariate tests of associations between presence of ticks (D. occidentalis, H. leporispalustris, I. angustus, I. auritulus, or I. spinipalpis) and environmental geographical information systems-remote sensing (GIS/ RS)-based data indicated that elevation, number of growing degree-days, and tasseled cap brightness, greenness, and wetness are especially useful predictors of presence of openly hostseeking ticks. Combinations of the above-mentioned GIS/RS-based data yielded significant logistic regression models for habitat suitability of host-seeking ticks for all five above-mentioned species. The model equations were used to create spatial surfaces of predicted presence of suitable habitat for openly host-seeking ticks in Mendocino County dense woodlands.
我们采用拖拽采样法，研究了加利福尼亚州北部沿海气候和生态多样的门多西诺县茂密林地中，进行开放式（非穴居性）宿主搜寻行为的硬蜱地理分布模式。基于这种采样方法的研究结果反映的是人类接触正在搜寻宿主的蜱的风险，而非蜱的真实分布情况。在78个地点进行的拖拽采样共采集到7860只太平洋硬蜱若虫或成虫（太平洋硬蜱，库利和科尔氏命名）、220只西方革蜱（马克思命名）、150只刺背硬蜱（哈德温和纳托尔命名）、15只野兔血蜱（帕卡德命名）、12只窄硬蜱（诺伊曼命名）、12只耳状硬蜱（诺伊曼命名），以及1只变异革蜱（赛命名）。太平洋硬蜱是加利福尼亚州莱姆病螺旋体伯氏疏螺旋体传播给人类主要媒介，在所检测的全部78个地点均有发现。西方革蜱是加利福尼亚州另一种常见的叮咬人类的蜱种，野兔血蜱通常出现在该县中部或东部与橡树相关的林地中。相比之下，三种硬蜱（窄硬蜱、耳状硬蜱和刺背硬蜱）最常出现在该县西部有红木的林地中进行开放式搜寻。窄硬蜱和刺背硬蜱偶尔会叮咬人类，并且是已知的伯氏疏螺旋体实验传播媒介。我们的研究首次收集到大量正在进行开放式宿主搜寻的刺背硬蜱。对蜱（西方革蜱、野兔血蜱、窄硬蜱、耳状硬蜱或刺背硬蜱）的存在与基于环境地理信息系统 - 遥感（GIS/RS）的数据之间的关联进行单变量测试表明，海拔、生长度日数、缨帽亮度、绿度和湿度是正在进行开放式宿主搜寻的蜱存在的特别有用的预测指标。上述基于GIS/RS的数据组合，得出了上述所有五个物种的宿主搜寻蜱栖息地适宜性的显著逻辑回归模型。模型方程用于创建门多西诺县茂密林地中正在进行开放式宿主搜寻的蜱适宜栖息地预测存在的空间表面。
