Population Biology, Ecology, and Evolution Program, Emory University, Atlanta, Georgia, USA.
Department of Zoology, Stockholm University, Stockholm, Sweden.
Ecol Lett. 2023 Nov;26(11):2003-2020. doi: 10.1111/ele.14319. Epub 2023 Oct 7.
Human activities have increased the intensity and frequency of natural stressors and created novel stressors, altering host-pathogen interactions and changing the risk of emerging infectious diseases. Despite the ubiquity of such anthropogenic impacts, predicting the directionality of outcomes has proven challenging. Here, we conduct a review and meta-analysis to determine the primary mechanisms through which stressors affect host-pathogen interactions and to evaluate the impacts stress has on host fitness (survival and fecundity) and pathogen infectivity (prevalence and intensity). We assessed 891 effect sizes from 71 host species (representing seven taxonomic groups) and 78 parasite taxa from 98 studies. We found that infected and uninfected hosts had similar sensitivity to stressors and that responses varied according to stressor type. Specifically, limited resources compromised host fecundity and decreased pathogen intensity, while abiotic environmental stressors (e.g., temperature and salinity) decreased host survivorship and increased pathogen intensity, and pollution increased mortality but decreased pathogen prevalence. We then used our meta-analysis results to develop susceptible-infected theoretical models to illustrate scenarios where infection rates are expected to increase or decrease in response to resource limitations or environmental stress gradients. Our results carry implications for conservation and disease emergence and reveal areas for future work.
人类活动增加了自然胁迫的强度和频率，并创造了新的胁迫源，改变了宿主-病原体相互作用，改变了新发传染病的风险。尽管这种人为影响无处不在，但预测结果的方向性一直具有挑战性。在这里，我们进行了一项综述和荟萃分析，以确定胁迫源影响宿主-病原体相互作用的主要机制，并评估应激对宿主适应性（生存和繁殖力）和病原体感染力（流行率和感染力）的影响。我们评估了 71 种宿主物种（代表七个分类群）和 78 种寄生虫类群的 891 个效应量，这些物种来自 98 项研究。我们发现，感染和未感染的宿主对胁迫源具有相似的敏感性，并且反应因胁迫源类型而异。具体而言，有限的资源会损害宿主的繁殖力并降低病原体的强度，而生物物理环境胁迫源（如温度和盐度）会降低宿主的存活率并增加病原体的强度，而污染则会增加死亡率但降低病原体的流行率。然后，我们使用荟萃分析结果开发了易感-感染理论模型，以说明在资源限制或环境胁迫梯度下，感染率预计会增加或减少的情况。我们的结果对保护和疾病的出现具有重要意义，并揭示了未来工作的方向。
