Evolution of an asymptomatic first stage of infection in a heterogeneous population
Evolution of an asymptomatic first stage of infection in a heterogeneous population
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DOI：
10.1098/rsif.2021.0175
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发表时间：
2021-06-16
影响因子：
3.9
通讯作者：
Wingreen, Ned S.
中科院分区：
文献类型：
--
作者：
Saad-Roy, Chadi M.;Grenfell, Bryan T.;Wingreen, Ned S.
病原体进化出不同的生活史策略，这在一定程度上取决于宿主种群的差异。宿主的一个中心特征是它们的群体结构（例如空间）。此外，宿主本身在新感染时也会表现出不同程度的症状；这种潜伏期是病原体的一个关键的生活史特性。通过进化流行病学模型，我们研究了种群结构对潜伏期进化动态的作用。我们专注于从第一感染阶段作为潜伏期函数的传播和进展的特定幂律式公式，假设如果宿主症状较轻，则组间与组内的传播比率会增加。我们发现，在相应的同质情况下存在唯一的 ESS 的情况下，简单的种群异质性可以导致零延迟和无限延迟的局部进化稳定策略（ESS）。此外，可以存在不止一种内部进化单一策略。我们发现，这种结果的多样性是由于病原体在第一感染阶段产生较少症状的跨群体传播的优势（可能是轻微的）。因此，我们的工作表明，允许没有症状的个体旅行可能会产生重要的意想不到的进化效应，因此从潜伏期的进化动态来看，这是根本性的问题。
Pathogens evolve different life-history strategies, which depend in part on differences in their host populations. A central feature of hosts is their population structure (e.g. spatial). Additionally, hosts themselves can exhibit different degrees of symptoms when newly infected; this latency is a key life-history property of pathogens. With an evolutionary-epidemiological model, we examine the role of population structure on the evolutionary dynamics of latency. We focus on specific power-law-like formulations for transmission and progression from the first infectious stage as a function of latency, assuming that the across-group to within-group transmission ratio increases if hosts are less symptomatic. We find that simple population heterogeneity can lead to local evolutionarily stable strategies (ESSs) at zero and infinite latency in situations where a unique ESS exists in the corresponding homogeneous case. Furthermore, there can exist more than one interior evolutionarily singular strategy. We find that this diversity of outcomes is due to the (possibly slight) advantage of across-group transmission for pathogens that produce fewer symptoms in a first infectious stage. Thus, our work reveals that allowing individuals without symptoms to travel can have important unintended evolutionary effects and is thus fundamentally problematic in view of the evolutionary dynamics of latency.