Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands.
Vector Borne Zoonotic Dis. 2011 May;11(5):523-32. doi: 10.1089/vbz.2010.0026. Epub 2010 Nov 17.
In a countrywide investigation of the ecological factors that contribute to Lyme borreliosis risk, a longitudinal study on population dynamics of the sheep tick Ixodes ricinus and their infections with Borrelia burgdorferi sensu lato (s.l.) was undertaken at 24 sites in The Netherlands from July 2006 to December 2007. Study sites were mature forests, dune vegetations, or new forests on land reclaimed from the sea. Ticks were sampled monthly and nymphal ticks were investigated for the presence of Borrelia spp. I. ricinus was the only tick species found. Ticks were found in all sites, but with significant spatial and temporal variations in density between sites. Peak densities were found in July and August, with lowest tick numbers collected in December and January. In some sites, questing activities of I. ricinus nymphs and adults were observed in the winter months. Mean monthly Borrelia infections in nymphs varied from 0% to 29.0% (range: 0%-60%), and several sites had significantly higher mean nymphal Borrelia infections than others. Four genospecies of Borrelia burgdorferi s.l. were found, with B. afzelii being dominant at most sites. Borrelia infection rates in nymphal ticks collected in July, September, and November 2006 were significantly higher (23.7%, p<0.01) than those in the corresponding months of 2007 (9.9%). The diversity in Borrelia genospecies between sites was significantly different (p<0.001). Habitat structure (tree cover) was an effective discriminant parameter in the determination of Borrelia infection risk, as measured by the proportion of nymphal ticks infected with B. burgdorferi s.l. Thickness of the litter layer and moss cover were positively related to nymphal and adult tick densities. The study shows that Borrelia-infected ticks are present in many forest and dune areas in The Netherlands and suggests that in such biotopes, which are used for a wide variety of recreational activities, the infection risk is high.
在一项针对导致莱姆病风险的生态因素的全国性调查中，对 2006 年 7 月至 2007 年 12 月在荷兰 24 个地点的绵羊蜱伊氏革蜱种群动态及其感染伯氏疏螺旋体（s.l.）进行了纵向研究。研究地点为成熟森林、沙丘植被或从海中开垦的新森林。每月采集蜱虫样本，并调查若虫蜱虫是否存在 Borrelia spp.。仅发现伊氏革蜱一种蜱虫。所有地点均发现蜱虫，但密度存在显著的空间和时间变化。密度峰值出现在 7 月和 8 月，12 月和 1 月采集的蜱虫数量最少。在一些地点，冬季观察到伊氏革蜱若虫和成虫的求偶活动。若虫的平均每月 Borrelia 感染率从 0%到 29.0%（范围：0%-60%）不等，几个地点的平均若虫 Borrelia 感染率明显高于其他地点。发现了 4 种伯氏疏螺旋体 s.l. 基因型，其中阿费尔型占多数地点的优势。2006 年 7 月、9 月和 11 月采集的若虫蜱的 Borrelia 感染率明显高于 2007 年同期（23.7%，p<0.01）。2006 年 7 月、9 月和 11 月采集的若虫蜱的 Borrelia 感染率明显高于 2007 年同期（23.7%，p<0.01）。各地点间 Borrelia 基因型的多样性有显著差异（p<0.001）。生境结构（树冠覆盖）是决定 Borrelia 感染风险的有效判别参数，以感染伯氏疏螺旋体 s.l. 的若虫蜱比例来衡量。凋落物层厚度和苔藓覆盖与若虫和成虫蜱的密度呈正相关。研究表明，伯氏疏螺旋体感染的蜱虫存在于荷兰的许多森林和沙丘地区，并表明在这些用于各种娱乐活动的生物区系中，感染风险很高。
