How will public and animal health interventions drive life-history evolution in parasitic nematodes?
How will public and animal health interventions drive life-history evolution in parasitic nematodes?
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DOI：
10.1017/s0031182008000309
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发表时间：
2008-11-01
期刊：
影响因子：
2.4
通讯作者：
Read, Andrew F.
中科院分区：
文献类型：
--
作者：
Lynch, Penelope A.;Grimm, Uwe;Read, Andrew F.
由人和牲畜的寄生线虫引起的感染可能会造成巨大的健康和经济损失。旨在减轻这些成本的治疗，如化疗和疫苗接种，会改变寄生虫的生存和繁殖，这是影响年龄到成熟、大小和繁殖力等生活史特征的主要选择压力。大多数作者认为，动物和公共卫生计划推动的生活史进化将在临床上有益，产生更小、更少繁殖力的蠕虫，几个数学模型支持这一观点。然而，使用长期干预措施(如接种疫苗)和定期重复的短期干预措施(如浇水)的数学模型，我们在这里表明，预期结果实际上取决于死亡率如何随蠕虫大小和发育状况的变化而变化。改变死亡率函数的干预措施可以施加选择压力，以缩短或延长成熟期，从而增加或减少虫子的繁殖力和大小。进化轨迹在很大程度上取决于有无干预的死亡率函数的细节。早些时候乐观地认为，卫生干预总是会促使较小、繁殖力较低的蠕虫进化，因此在临床上破坏性较小的蠕虫还为时过早。
Infection caused by parasitic nematodes of humans and livestock can have significant health and economic costs. Treatments aimed at alleviating these costs, such as chemotherapy and vaccination, alter parasite survival and reproduction, the main selective pressures shaping life-history traits such as age to maturity, size and fecundity. Most authors have argued that the life-history evolution prompted by animal and public health programmes would be clinically beneficial, generating smaller, less fecund worms, and several mathematical models support this view. However, using mathematical models of long-lasting interventions, such as vaccination, and regularly repeated short interventions, such as drenching, we show here that the expected outcome actually depends on how mortality rates vary as a function of worm size and developmental status. Interventions which change mortality functions can exert selection pressure to either shorten or extend the time to maturity, and thus increase or decrease worm fecundity and size. The evolutionary trajectory depends critically on the details of the mortality functions with and without the intervention. Earlier optimism that health interventions would always prompt the evolution of smaller, less fecund and hence clinically less damaging worms is premature.