Department of Laboratory Medicine, University of California-San Francisco, San Francisco, California, USA.
Vector Borne Zoonotic Dis. 2012 Aug;12(8):623-32. doi: 10.1089/vbz.2011.0783. Epub 2012 May 18.
Global changes such as deforestation, climate change, and invasive species have the potential to greatly alter zoonotic disease systems through impacts on biodiversity. This study examined the impact of the invasive pathogen that causes sudden oak death (SOD) on the ecology of Lyme disease in California. The Lyme disease bacterium, Borrelia burgdorferi, is maintained in the far western United States by a suite of animal reservoirs including the dusky-footed woodrat (Neotoma fuscipes) and deer mouse (Peromyscus maniculatus), and is transmitted by the western black-legged tick (Ixodes pacificus). Other vertebrates, such as the western fence lizard (Sceloporus occidentalis), are important tick hosts but are not reservoirs of the pathogen. Previous work found that higher levels of SOD are correlated with greater abundance of P. maniculatus and S. occidentalis and lower N. fuscipes abundance. Here we model the contribution of these tick hosts to Lyme disease risk and also evaluate the potential impact of SOD on infection prevalence of the tick vector. By empirically parameterizing a static model with field and laboratory data on tick hosts, we predict that SOD reduces an important index of disease risk, nymphal infection prevalence, leading to a reduction in Lyme disease risk in certain coastal woodlands. Direct observational analysis of the impact of SOD on nymphal infection prevalence supports these model results. This study underscores the important direct and indirect impacts of invasive plant pathogens on biodiversity, the transmission cycles of zoonotic diseases, and ultimately human health.
全球变化，如森林砍伐、气候变化和入侵物种，有可能通过对生物多样性的影响，极大地改变人畜共患病系统。本研究调查了导致突发性橡树死亡（SOD）的入侵病原体对加利福尼亚莱姆病生态学的影响。莱姆病细菌，伯氏疏螺旋体，在美国西部偏远地区由一系列动物宿主维持，包括暗足木鼠（Neotoma fuscipes）和鹿鼠（Peromyscus maniculatus），并由太平洋硬蜱（Ixodes pacificus）传播。其他脊椎动物，如西部壁蜥（Sceloporus occidentalis），是重要的蜱宿主，但不是病原体的宿主。先前的研究发现，较高水平的 SOD 与 P. maniculatus 和 S. occidentalis 的丰度增加以及 N. fuscipes 的丰度降低有关。在这里，我们模拟了这些蜱宿主对莱姆病风险的贡献，也评估了 SOD 对蜱媒介感染率的潜在影响。通过用蜱宿主的实地和实验室数据对静态模型进行经验参数化，我们预测 SOD 降低了疾病风险的一个重要指标，即若虫感染率，从而降低了某些沿海林地的莱姆病风险。对 SOD 对若虫感染率的直接观察分析支持这些模型结果。本研究强调了入侵植物病原体对生物多样性、人畜共患病传播周期以及最终人类健康的重要直接和间接影响。
