Institute of Biology, Freie Universität Berlin, Berlin, Germany.
Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
Nat Commun. 2022 Aug 26;13(1):5023. doi: 10.1038/s41467-022-32118-1.
Following an infection, hosts cannot always clear the pathogen, instead either dying or surviving with a persistent infection. Such variation is ecologically and evolutionarily important because it can affect infection prevalence and transmission, and virulence evolution. However, the factors causing variation in infection outcomes, and the relationship between clearance and virulence are not well understood. Here we show that sustained persistent infection and clearance are both possible outcomes across bacterial species showing a range of virulence in Drosophila melanogaster. Variation in virulence arises because of differences in the two components of virulence: bacterial infection intensity inside the host (exploitation), and the amount of damage caused per bacterium (per parasite pathogenicity). As early-phase exploitation increased, clearance rates later in the infection decreased, whereas there was no apparent effect of per parasite pathogenicity on clearance rates. Variation in infection outcomes is thereby determined by how virulence - and its components - relate to the rate of pathogen clearance. Taken together we demonstrate that the virulence decomposition framework is broadly applicable and can provide valuable insights into host-pathogen interactions.
感染后，宿主并非总能清除病原体，而是要么死亡，要么持续感染。这种变异在生态学和进化上是很重要的，因为它会影响感染的流行和传播，以及毒力的进化。然而，导致感染结果变异的因素，以及清除和毒力之间的关系还没有得到很好的理解。在这里，我们表明，在表现出一系列在黑腹果蝇中不同毒力的细菌物种中，持续的持续感染和清除都是可能的结果。毒力的变异是由于毒力的两个组成部分的差异：宿主内部细菌感染的强度（利用），以及每个细菌造成的损害量（寄生虫每单位致病性）。随着早期利用的增加，感染后期的清除率降低，而寄生虫每单位致病性对清除率没有明显影响。因此，感染结果的变异是由毒力及其组成部分与病原体清除率的关系决定的。综上所述，我们证明了毒力分解框架具有广泛的适用性，并能为宿主-病原体相互作用提供有价值的见解。
