Within-host priority effects and epidemic timing determine outbreak severity in co-infected populations
Within-host priority effects and epidemic timing determine outbreak severity in co-infected populations
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DOI：
10.1098/rspb.2020.0046
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发表时间：
2020-03-11
影响因子：
4.7
通讯作者：
Rudolf, Volker H. W.
中科院分区：
文献类型：
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作者：
Clay, Patrick A.;Duffy, Meghan A.;Rudolf, Volker H. W.
宿主被多个病原体物种混合感染是普遍存在的，但预测它们对疾病的影响仍然具有挑战性。宿主内共感染病原体之间的相互作用可以改变病原体的传播，对传播的影响通常取决于病原体在宿主内的相对到达顺序(宿主内的优先效应)。然而，目前尚不清楚这些宿主内的优先效应如何影响多病原体流行，特别是当病原体到达宿主种群规模的顺序不同时。在这里，我们结合浮游动物及其自然共生的真菌和细菌病原体的模型和实验来研究宿主内的优先效应如何影响多病原体流行。在单宿主尺度上测量的带有宿主内优先效应的流行病学模型预测，相对于真菌流行病，细菌流行的开始日期提前将降低多病原体环境中的平均细菌流行率，而没有宿主内优先效应的模型预测相反的效果。我们用实验性的多病原体流行来检验这些预测。经验动力学与包括宿主内优先效应在内的模型的预测相匹配，提供了宿主内优先效应影响流行动力学的证据。总体而言，宿主内的优先效应可能是预测未来多病原体流行动态的关键因素，特别是在疾病物候变化改变宿主内感染顺序的情况下。
Co-infections of hosts by multiple pathogen species are ubiquitous, but predicting their impact on disease remains challenging. Interactions between co-infecting pathogens within hosts can alter pathogen transmission, with the impact on transmission typically dependent on the relative arrival order of pathogens within hosts (within-host priority effects). However, it is unclear how these within-host priority effects influence multi-pathogen epidemics, particularly when the arrival order of pathogens at the host-population scale varies. Here, we combined models and experiments with zooplankton and their naturally co-occurring fungal and bacterial pathogens to examine how within-host priority effects influence multi-pathogen epidemics. Epidemiological models parametrized with within-host priority effects measured at the single-host scale predicted that advancing the start date of bacterial epidemics relative to fungal epidemics would decrease the mean bacterial prevalence in a multi-pathogen setting, while models without within-host priority effects predicted the opposite effect. We tested these predictions with experimental multi-pathogen epidemics. Empirical dynamics matched predictions from the model including within-host priority effects, providing evidence that within-host priority effects influenced epidemic dynamics. Overall, within-host priority effects may be a key element of predicting multi-pathogen epidemic dynamics in the future, particularly as shifting disease phenology alters the order of infection within hosts.