Xu Lei, Schmid Boris V, Liu Jun, Si Xiaoyan, Stenseth Nils Chr, Zhang Zhibin
State Key Laboratory of Integrated Management on Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Blindern, Oslo 0316, Norway.
Proc Biol Sci. 2015 Feb 7;282(1800):20141846. doi: 10.1098/rspb.2014.1846.
Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change.
鼠疫是历史上三次毁灭性大流行的病原体，目前是一种再度出现的疾病，这可能是由于气候变化和其他人为变化所致。如果不了解鼠疫系统在其营养网络中对人为或气候变化的反应，就无法有效地预测鼠疫爆发高风险年份，从而妨碍我们有效预防和控制该疾病的能力。在此，我们利用监测数据，应用结构方程模型来揭示两种截然不同的啮齿动物系统中鼠疫流行的驱动因素：独居的达乌尔黄鼠和群居的长爪沙鼠。我们发现，达乌尔黄鼠中的鼠疫流行与它的营养网络没有明显关联，因此监测工作应集中于直接在这个生态系统中检测鼠疫。另一方面，长爪沙鼠中的鼠疫强烈地嵌入在一个由气候、植被以及啮齿动物和跳蚤密度构成的复杂但可理解的营养网络中，这使得该生态系统适合采用更复杂的低成本监测方法，如遥感。至于这两种啮齿动物的营养网络，我们发现植被增加与两个生态系统中较高的温度和降水量呈正相关。我们还发现植被与黄鼠密度呈正相关，但与长爪沙鼠密度呈负相关。因此，我们的研究表明，过去的监测记录可如何用于设计和改进现有的鼠疫预防和控制措施，通过针对各个鼠疫疫源地进行调整。在当前气候变化盛行的情况下，这样的措施确实非常必要。
