Within-Host Priority Effects Systematically Alter Pathogen Coexistence
Within-Host Priority Effects Systematically Alter Pathogen Coexistence
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DOI：
10.1086/701126
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发表时间：
2019-02-01
影响因子：
2.9
通讯作者：
Duffy, Meghan A.
中科院分区：
文献类型：
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作者：
Clay, Patrick A.;Dhir, Kailash;Duffy, Meghan A.
宿主种群的共感染改变病原体的流行率、宿主死亡率和病原体的进化。由于病原体竞争有限的资源，多种病原体能否在宿主种群中共存取决于它们的宿主内相互作用，而宿主内相互作用又取决于病原体感染宿主的顺序（宿主内优先效应）。然而，病原体共存的宿主内优先效应的后果尚未得到检验。使用实验室研究与共感染的浮游动物系统，我们发现，病原体增加健身共感染的主机时，他们是第二个病原体感染的主机，相比，当他们是第一个病原体感染的主机。利用这些结果，我们参数化了具有优先效应的病原体共存模型，发现病原体共存（1）当优先效应增加第一种病原体到达共感染宿主的适合度时减少，（2）当优先效应增加第二种病原体到达共感染宿主的适合度时增加。我们还确定了自然条件，在这些条件下，我们预计东道国内的优先效应将促进我们系统中的共存。这些结果是共同感染宿主中病原体流行和感染顺序之间的反馈回路所产生的正或负频率依赖性的结果。这表明优先效应可以系统地改变宿主种群中病原体共存的条件，从而改变病原体群落结构，并可能通过紧急过程改变宿主死亡率和病原体进化。
Coinfection of host populations alters pathogen prevalence, host mortality, and pathogen evolution. Because pathogens compete for limiting resources, whether multiple pathogens can coexist in a host population can depend on their within-host interactions, which, in turn, can depend on the order in which pathogens infect hosts (within-host priority effects). However, the consequences of within-host priority effects for pathogen coexistence have not been tested. Using laboratory studies with a coinfected zooplankton system, we found that pathogens had increased fitness in coinfected hosts when they were the second pathogen to infect a host, compared to when they were the first pathogen to infect a host. With these results, we parameterized a pathogen coexistence model with priority effects, finding that pathogen coexistence (1) decreased when priority effects increased the fitness of the first pathogen to arrive in coinfected hosts and (2) increased when priority effects increased the fitness of the second pathogen to arrive in coinfected hosts. We also identified the natural conditions under which we expect within-host priority effects to foster coexistence in our system. These outcomes were the result of positive or negative frequency dependence created by feedback loops between pathogen prevalence and infection order in coinfected hosts. This suggests that priority effects can systematically alter conditions for pathogen coexistence in host populations, thereby changing pathogen community structure and potentially altering host mortality and pathogen evolution via emergent processes.