'Small worlds' and the evolution of virulence: infection occurs locally and at a distance
'Small worlds' and the evolution of virulence: infection occurs locally and at a distance
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DOI：
10.1098/rspb.1999.0869
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发表时间：
1999-10-07
影响因子：
4.7
通讯作者：
Sasaki, A
中科院分区：
文献类型：
--
作者：
Boots, M;Sasaki, A
为什么有些疾病比其他疾病更致命？疟疾等病媒传染的疾病和霍乱等水媒传染的疾病通常比通过直接传染传播的疾病更致命。媒介传播和水媒传播疾病的一个特点是它们能够远距离传播，从而使远离受感染者的易感者受到感染。在这里，我们表明，这种能力的病原体感染遥远的个人在一个空间结构的主机人口导致一个更致命的病原体的演变。我们使用一个格子模型，其中繁殖是局部的，但感染可以在完全局部到完全全局之间变化。在完全全局感染的情况下，进化稳定策略（ESS）与平均场模型相同，而随着感染变得更加局部，预测毒力较低。有一个典型的时期，相对温和的毒力增加，然后随着全球感染比例的增加，随着我们超越“关键连接”，毒力迅速上升。鉴于最近的研究强调了人类群体中存在“小世界”网络，我们的研究结果表明，如果世界变得“更小”，随着人口的联系越来越紧密，疾病可能会进化出更高的毒力。
Why are some diseases more virulent than others? Vector-borne diseases such as malaria and water-borne diseases such as cholera are generally more virulent than diseases spread by direct contagion. One factor that characterizes both vector- and water-borne diseases is their ability to spread over long distances, thus causing infection of susceptible individuals distant from the infected individual. Here we show that this ability of the pathogen to infect distant individuals in a spatially structured host population leads to the evolution of a more virulent pathogen. We use a lattice model in which reproduction is local but infection can vary between completely local to completely global. With completely global infection the evolutionarily stable strategy (ESS) is the same as in mean-field models while a lower virulence is predicted as infection becomes more local. There is characteristically a period of relatively moderate increase in virulence followed by a more rapid rise with increasing proportions of global infection as we move beyond a 'critical connectivity'. In the light of recent work emphasizing the existence of 'small world' networks in human populations, our results suggests that if the world is getting 'smaller'-as populations become more connected-diseases may evolve higher virulence.