Merler S, Furlanello C, Chemini C, Nicolini G
Istituto per la Ricerca Scientifica e Technologica, Trento, Italy.
J Med Entomol. 1996 Nov;33(6):888-93. doi: 10.1093/jmedent/33.6.888.
Cases of Lyme disease and tick-borne encephalitis were recognized recently in the Province of Trento, Italian Alps. Assessment of areas of potential risk for these tick-borne diseases is carried out by a model based on classification and regression trees (CART), using both discrete and continuous variables. Data on Ixodes ricinus (L.) occurrence resulted from extensive sampling carried out by standard methods in 99 sites over an area of approximately 2,700 km2 in the Province of Trento. A series of environmental parameters were recorded from each site and population densities of roe deer, Capreolus capreolus (L.), were considered. The CART model discriminates 2 variables that appear to have the greatest effect on the mesoscale occurrence of ticks: altitude and geological substratum, with a drastic decrease of tick frequency above an altitude of approximately 1,100 m and on volcanic substrata. The model is effective in identifying the mesoscale areas at greater potential risk, with a relatively low sampling effort.
意大利阿尔卑斯山特伦托省最近发现了莱姆病和蜱传脑炎病例。通过基于分类与回归树（CART）的模型，利用离散变量和连续变量对这些蜱传疾病的潜在风险区域进行评估。蓖麻硬蜱（Ixodes ricinus (L.)）出现情况的数据来自于在特伦托省约2700平方公里区域内99个地点采用标准方法进行的广泛采样。记录了每个地点的一系列环境参数，并考虑了狍（Capreolus capreolus (L.)）的种群密度。CART模型区分出对蜱虫中尺度出现影响最大的两个变量：海拔和地质基质，在海拔约1100米以上以及火山基质上蜱虫频率急剧下降。该模型能够以相对较低的采样工作量有效识别出中尺度上潜在风险较大的区域。
