Kamo Masashi, Boots Michael
Department of Biology, Faculty of Science, Kyushu University Graduate Schools, Fukuoka 812-8581, Japan.
J Theor Biol. 2004 Dec 7;231(3):435-41. doi: 10.1016/j.jtbi.2004.07.005.
The idea that parasites with long-lived infective stages may evolve higher virulence has received considerable attention. This idea is called 'the curse of the pharaoh' because of the hypothesis that the death of Lord Carnavon was caused by very long-lived propagules of a highly virulent infectious disease. Here, we examined the evolution of diseases that transmit via free-living stages in a spatial context. We show that, if virulence evolves independently of transmission, long-lived infective stages can select for higher virulence. There is always the evolution of a finite transmission rate, which becomes higher when the infective stages are shorter lived. When a trade-off occurs between transmission and virulence, we show that there is no evidence for the curse of the pharaoh. Indeed, higher transmission and therefore virulence may be selected for by shorter rather than long-lived infective stages.
具有长期存活感染阶段的寄生虫可能会进化出更高的毒力这一观点已受到广泛关注。由于有假说认为卡那封勋爵的死亡是由一种高毒力传染病的极长期存活传播体所致，所以这个观点被称为“法老的诅咒”。在此，我们在空间背景下研究了通过自由生活阶段传播的疾病的进化。我们表明，如果毒力的进化与传播无关，长期存活的感染阶段会选择更高的毒力。总会有有限传播率的进化，当感染阶段寿命较短时，传播率会变得更高。当在传播和毒力之间出现权衡时，我们表明没有证据支持法老的诅咒。实际上，较短而非长期存活的感染阶段可能会选择更高的传播率以及因此更高的毒力。
