Gandon S
Laboratoire d'Ecologie, CNRS-UMR 7625, Université Pierre et Marie Curie, Paris, France.
Proc Biol Sci. 1998 Aug 22;265(1405):1545-52. doi: 10.1098/rspb.1998.0470.
The 'curse of the pharaoh' has been used as a metaphor for the hypothesis that higher parasite propagule survival selects for higher virulence. Indeed, the mysterious death of Lord Carnavon after entering the tomb of the Egyptian pharaoh Tutankhamen could potentially be explained by an infection with a highly virulent and very long-lived pathogen. In this paper, I investigate whether parasite virulence increases with high propagule survival. In this respect, I derive an analytic expression of the evolutionarily stable level of parasite virulence as a function of propagule survival rate when the host-parasite system has reached a stable ecological equilibrium. This result shows that, if multiple infection occurs, higher propagule survival generally increases parasite virulence. This effect is enhanced when parasite dispersal coevolves with parasite virulence. In a more general perspective, the model shows the importance of taking into account the combination of direct and indirect effects (which I call inclusive effects) of higher transmission ability on the evolution of parasite virulence. The recognition of these effects has several practical implications for virulence management.
“法老的诅咒”被用作一种隐喻，来形容这样一种假说：较高的寄生虫繁殖体存活率会促使其向更高的毒力进化。的确，卡那封勋爵在进入埃及法老图坦卡蒙的陵墓后神秘死亡，这有可能是由感染了一种高毒力且寿命极长的病原体所致。在本文中，我研究了寄生虫的毒力是否会随着高繁殖体存活率而增加。在这方面，当宿主 - 寄生虫系统达到稳定的生态平衡时，我推导出了作为繁殖体存活率函数的寄生虫毒力进化稳定水平的解析表达式。结果表明，如果发生多重感染，较高的繁殖体存活率通常会增加寄生虫的毒力。当寄生虫传播与寄生虫毒力共同进化时，这种效应会增强。从更一般的角度来看，该模型显示了在寄生虫毒力进化过程中，考虑更高传播能力的直接和间接效应（我称之为包容性效应）组合的重要性。认识到这些效应对于毒力管理具有若干实际意义。
