Spatially structured superinfection and the evolution of disease virulence
Spatially structured superinfection and the evolution of disease virulence
复制标题
DOI：
10.1016/j.tpb.2005.12.004
复制
发表时间：
2006-06-01
影响因子：
1.4
通讯作者：
Szymanski, Boleslaw K.
中科院分区：
文献类型：
--
作者：
Caraco, Thomas;Glavanakov, Stephan;Szymanski, Boleslaw K.
当不同毒力的病原菌竞争宿主时，疾病传播的空间结构既可以控制毒力的进化水平，也可以控制菌株共存的模式。我们开发了一个空间详细的重复感染模型，这是病原体菌株之间竞争的一种形式；重复感染的可能性明确地取决于毒力水平的差异。我们应用自适应动力学的方法来解决空间动力学和进化的相互作用。平均场近似预测进化到临界点；能够动态持续的毒力的任何小幅增加都是有利的。配对近似和详细模型的模拟都表明，空间结构限制了疾病的毒力。增强的空间聚集性降低了单一菌株持续的最大毒力，更重要的是，降低了菌株竞争下的收敛稳定毒力水平。空间细节模型预测，在给定毒力差异的情况下，增加重复感染的可能性会增加菌株间共存的可能性。当毒力不同的菌株可以在生态上共存时，我们的结果可能会为管理局部传播的疾病提供政策建议。从对近似的平衡密度比较，我们发现，将更强的毒力菌株引入到由毒力较低的菌株感染的宿主群体中，有时可以降低总宿主死亡率，增加全球宿主密度。(C)2006 Elsevier Inc.保留所有权利。
When pathogen strains differing in virulence compete for hosts, spatial structuring of disease transmission can govern both evolved levels of virulence and patterns in strain coexistence. We develop a spatially detailed model of superinfection, a form of contest competition between pathogen strains; the probability of superinfection depends explicitly on the difference in levels of virulence. We apply methods of adaptive dynamics to address the interplay of spatial dynamics and evolution. The mean-field approximation predicts evolution to criticality; any small increase in virulence capable of dynamical persistence is favored. Both pair approximation and simulation of the detailed model indicate that spatial structure constrains disease virulence. Increased spatial clustering reduces the maximal virulence capable of single-strain persistence and, more importantly, reduces the convergent-stable virulence level under strain competition. The spatially detailed model predicts that increasing the probability of superinfection, for given difference in virulence, increases the likelihood of between-strain coexistence. When strains differing in virulence can coexist ecologically, our results may suggest policies for managing diseases with localized transmission. Comparing equilibrium densities from the pair approximation, we find that introducing a more virulent strain into a host population infected by a less virulent strain can sometimes reduce total host mortality and increase global host density. (c) 2006 Elsevier Inc. All rights reserved.