Data from: Coinfection timing drives host population dynamics through changes in virulence

Infections of one host by multiple parasites are common, and several studies have found that the order of parasite invasion can affect both within-host competition and disease severity. However, it is unclear to what extent coinfection timing might be important to consider when modeling parasite impacts on host populations. Using a model system of two viruses infecting barley, we found that simultaneous infections of the two viruses were significantly more damaging to hosts than sequential coinfections. While priority effects were evident in within-host concentrations of sequential coinfections, priority did not influence any parameters, such as virulence or transmission rate, that affect host population dynamics. We built a susceptible-infected model to examine whether the observed difference in coinfection virulence could impact host population dynamics under a range of scenarios. We found that coinfection timing can have an important, but context dependent, effect on projected host population dynamics. Studies that examine only simultaneous coinfections could inflate disease impact predictions.

多种病原体（parasite）侵染同一宿主的现象普遍存在，多项研究已证实，病原体入侵宿主的先后顺序会同时影响宿主体内的竞争过程与疾病严重程度。然而，在构建病原体对宿主种群影响的模型时，共感染（coinfection）的发生时机究竟需要在多大程度上纳入考量，目前尚不明确。本研究以侵染大麦的两种病毒为模式系统，研究发现，两种病毒的同时共感染对宿主造成的损害显著高于顺序共感染。尽管在顺序共感染的宿主体内病毒浓度中观测到了优先效应（priority effects），但该优先效应并未对影响宿主种群动态的相关参数（如毒力（virulence）、传播速率（transmission rate）等）产生影响。我们构建了易感-感染（susceptible-infected）模型，以探究观测到的共感染毒力差异是否会在多种情景下对宿主种群动态产生影响。研究结果表明，共感染时机对宿主种群动态的预测结果可产生重要但依赖于具体情境的影响。仅关注同时共感染的相关研究，可能会高估疾病影响的预测结果。