Department of Biology, University of Oxford, Oxford, UK.
Proc Biol Sci. 2024 Feb 14;291(2016):20232043. doi: 10.1098/rspb.2023.2043. Epub 2024 Feb 7.
By definition, all pathogens cause some level of harm to their hosts. If this harm occurs while the pathogen is transmitting, it can negatively affect the pathogen's fitness by shortening the duration over which transmission can occur. However, many of the factors that increase virulence (i.e. harm to host) also promote transmission, driving the pathogen population towards an optimal state of intermediate virulence. A wider spectrum of virulence may be maintained among pathogen populations which are structured into multiple discrete strains though direct resource and immune-mediated competition. These various evolutionary outcomes, and the effects of medical and public health interventions, are best understood within a framework that recognizes the complex relationship between transmission and virulence in the context of the antigenic diversity of the pathogen population.
从定义上讲，所有病原体都会对其宿主造成一定程度的伤害。如果这种伤害发生在病原体传播过程中，它可能会通过缩短传播发生的时间来对病原体的适应性产生负面影响。然而，许多增加毒力（即对宿主的伤害）的因素也会促进传播，从而使病原体种群朝着中间毒力的最佳状态发展。通过直接的资源和免疫介导的竞争，具有多种离散菌株结构的病原体种群可能会维持更广泛的毒力谱。在认识到病原体种群的抗原多样性背景下，传播和毒力之间复杂关系的框架内，才能最好地理解这些不同的进化结果以及医学和公共卫生干预措施的影响。
