Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
United States Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711, USA.
Proc Biol Sci. 2020 Jan 29;287(1919):20192597. doi: 10.1098/rspb.2019.2597. Epub 2020 Jan 22.
A key challenge surrounding ongoing climate shifts is to identify how they alter species interactions, including those between hosts and parasites. Because transmission often occurs during critical time windows, shifts in the phenology of either taxa can alter the likelihood of interaction or the resulting pathology. We quantified how phenological synchrony between vulnerable stages of an amphibian host () and infection by a pathogenic trematode () determined infection prevalence, parasite load and host pathology. By tracking hosts and parasite infection throughout development between low- and high-elevation regions (San Francisco Bay Area and the Southern Cascades (Mt Lassen)), we found that when phenological synchrony was high (Bay Area), each established parasite incurred a 33% higher probability of causing severe limb malformations relative to areas with less synchrony (Mt Lassen). As a result, hosts in the Bay Area had up to a 50% higher risk of pathology even while controlling for the mean infection load. Our results indicate that host-parasite interactions and the resulting pathology were the joint product of infection load and phenological synchrony, highlighting the sensitivity of disease outcomes to forecasted shifts in climate.
一个围绕持续气候变化的关键挑战是确定它们如何改变物种相互作用，包括宿主和寄生虫之间的相互作用。由于传播通常发生在关键的时间窗口内，因此两个分类群的物候变化都可能改变相互作用的可能性或产生的病理学。我们量化了脆弱阶段的两栖类宿主和感染性吸虫之间的物候同步性如何决定感染率、寄生虫负荷和宿主病理学。通过在低海拔和高海拔地区（旧金山湾区和南喀斯喀特山脉（拉森山））跟踪宿主和寄生虫的整个发育过程，我们发现当物候同步性高（湾区）时，与同步性较低的地区（拉森山）相比，每只已建立的寄生虫导致严重肢体畸形的可能性增加 33%。结果，即使在控制平均感染负荷的情况下，湾区的宿主发生病理学的风险也高达 50%。我们的研究结果表明，宿主-寄生虫相互作用和由此产生的病理学是感染负荷和物候同步性的共同产物，突出了疾病结果对预测气候变化的敏感性。
