Evolution of virulence in emerging epidemics.
Evolution of virulence in emerging epidemics.
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DOI：
10.1371/journal.ppat.1003209
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发表时间：
2013-03
期刊：
影响因子：
6.7
通讯作者：
Gandon S
中科院分区：
文献类型：
--
作者：
Berngruber TW;Froissart R;Choisy M;Gandon S
理论预测，病原体毒力和水平传播的选择在流行病开始时最高，但此后随着流行病耗尽易感宿主库而下降。我们通过跟踪在大肠杆菌连续培养物中发生的实验性流行病中潜伏噬菌体λ和其毒性突变体λ cI 857之间的竞争来验证这一预测。正如预期的那样，强毒λcI857在流行的早期阶段非常有利，但随着流行率的增加，它失去了与潜伏病毒的竞争。我们发现，所观察到的瞬时选择的毒力和水平传播的进化流行病学理论的框架内，可以得到充分的解释。对我们预测的实验验证是迈向新兴传染病毒力演变预测理论的关键一步。为什么有些病原体比其他病原体更具毒性？理论预测，在不太可能传播到新的易感宿主的时候，“保持宿主存活”的病原体有时可以胜过有毒病原体。然而，这种寻找新的易感宿主的前景在整个流行病中会发生变化。在流行病的早期阶段，易感宿主是丰富的，并且在水平传播方面投入更多的强毒病原体应该赢得竞争。后来，感染的传播减少了易感宿主的库，并可能逆转对毒力的选择。这可能有利于良性病原体后，急性期的流行。我们模拟这种短暂的毒性效益，并预测流行病期间病原体的流行病学和演变。为了检验这些预测，我们在实验流行病中监测了温和细菌病毒λ及其毒性突变体λcI857的竞争。我们的实验结果与我们所有的理论预测非常吻合。这证明了进化流行病学预测正在进行的流行病中毒力选择的能力。
Theory predicts that selection for pathogen virulence and horizontal transmission is highest at the onset of an epidemic but decreases thereafter, as the epidemic depletes the pool of susceptible hosts. We tested this prediction by tracking the competition between the latent bacteriophage λ and its virulent mutant λcI857 throughout experimental epidemics taking place in continuous cultures of Escherichia coli. As expected, the virulent λcI857 is strongly favored in the early stage of the epidemic, but loses competition with the latent virus as prevalence increases. We show that the observed transient selection for virulence and horizontal transmission can be fully explained within the framework of evolutionary epidemiology theory. This experimental validation of our predictions is a key step towards a predictive theory for the evolution of virulence in emerging infectious diseases. Why are some pathogens more virulent than others? Theory predicts that pathogens that ‘keep their host alive’ can sometimes outcompete virulent pathogens in times when transmission to new susceptible hosts is unlikely. Yet, this prospect of finding a new susceptible host changes itself throughout an epidemic. In the early stage of an epidemic susceptible hosts are abundant and virulent pathogens that invest more into horizontal transmission should win the competition. Later on, the spread of the infection reduces the pool of susceptible hosts and may reverse the selection on virulence. This may favor benign pathogens after the acute phase of the epidemic. We model this transient benefit for virulence and predict both the epidemiology and the evolution of pathogens during an epidemic. To put these predictions to the test we monitor the competition of the temperate bacterial virus λ and its virulent mutant λcI857 in experimental epidemics. Our experimental results agree remarkably well with all our theoretical predictions. This demonstrates the ability of evolutionary epidemiology to predict selection for virulence in an ongoing epidemic.
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DOI：
10.1073/pnas.0500078102
发表时间：
2005-05-24
影响因子：
11.1
作者：
de Roode, JC;Pansini, R;Read, AF
通讯作者：
Read, AF
影响因子：
5.4
作者：
Berngruber, Thomas W.;Weissing, Franz J.;Gandon, Sylvain
通讯作者：
Gandon, Sylvain
影响因子：
4.3
作者：
Adiwijaya BS;Kieffer TL;Henshaw J;Eisenhauer K;Kimko H;Alam JJ;Kauffman RS;Garg V
通讯作者：
Garg V
影响因子：
2
作者：
LENSKI, RE;MAY, RM
通讯作者：
MAY, RM
影响因子：
4.3
作者：
Joh, Richard I.;Weitz, Joshua S.
通讯作者：
Weitz, Joshua S.