时空异质性解耦两栖动物壶菌病感染参数
Spatiotemporal heterogeneity decouples infection parameters of amphibian chytridiomycosis
331字
2020-01-06 10:03
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火星译客
  1. Emerging infectious diseases are responsible for declines in wildlife populations around the globe. Mass mortality events associated with emerging infectious diseases are often associated with high number of infected individuals (prevalence) and high pathogen loads within individuals (intensity). At the landscape scale spatial and temporal variation in environmental conditions can alter the relationship between these infection parameters and blur the overall picture of disease dynamics.
  2. Quantitative estimates of how infection parameters covary with environmental heterogeneity at the landscape scale are scarce. Predicting rates of pathogen transmission and identifying wild populations at risk of disease epidemics requires that we elucidate the factors that shape, and potentially decouple, the link between pathogen prevalence and intensity of infection over complex ecological landscapes.
  3. Using a network of 41 populations of the amphibian host Rana pipiensin Ontario, Canada, we present the spatial and temporal heterogeneity in pathogen prevalence and intensity of infection of the chytrid fungusBatrachochytrium dendrobatidis (Bd), across a 3‐year period. We then quantify how covariation between both infection parameters measured during late summer, are modified by previously experienced spatiotemporal environmental heterogeneity across 14 repeat sampled populations.
  4. Late summer Bd infection parameters are governed, at least in part, by different environmental factors operating during separate host life history events. Our results provide evidence for a relationship betweenBd prevalence and thermal regimes prior to host breeding at the site level, and a relationship between intensity of infection and aquatic conditions (precipitation, hydroshed size and river density) throughout host breeding period at the site level. This demonstrates that microclimatic variation within temporal windows, can drive divergent patterns of pathogen dynamics within and across years, by effecting changes in host behaviour which interfere with the pathogen's ability to infect and re‐infect hosts.
  5. A clearer understanding of the role that spatiotemporal heterogeneity has upon infection parameters will provide valuable insights into host‐pathogen epidemiology, as well as more fundamental aspects of the ecology and evolution of interspecific interactions.
  1. 新兴传染病是造成全球野生动植物种群减少的原因。与新兴传染病相关的大规模死亡事件通常与受感染个体数量高(患病率)和个体内部病原体负荷高(强度)有关。在景观尺度上,环境条件的时空变化会改变这些感染参数之间的关系,并使疾病动态的整体图景模糊。
  2. 在景观尺度上,关于感染参数如何随环境异质性变化的定量估计很少。预测病原体的传播速度并确定有疾病流行风险的野生种群需要我们阐明影响复杂生态环境中病原体流行与感染强度之间联系的因素,并可能使其脱钩。
  3. 我们使用加拿大安大略省两栖类寄主斑点青蛙的41个种群组成的网络,在3年的时间里提出了蛙壶菌病原体流行率和感染强度的时空异质性。然后,我们量化了在14个重复采样的人群中,夏末时空环境异质性如何修正了夏末测量的两个感染参数之间的协方差。
  4. 夏末感染参数至少部分由在单独的宿主生活史事件中运行的不同环境因素决定。我们的结果提供了证据,表明在站点水平上宿主繁殖之前, 流行与热状况之间的关系,以及在站点水平上整个宿主繁殖期的感染强度与水生条件(降水、集水区大小和河流密度)之间的关系。这表明,时间窗内的微气候变化可通过影响宿主行为的变化,从而干扰病原体感染和重新感染宿主的能力,从而推动病原体动力学在多年内和跨年的不同模式。
  5. 对时空异质性对感染参数的作用的更清楚的了解将为寄主——病原体流行病学以及生态学和种间相互作用的进化的更基本方面提供有价值的见解。

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