Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada.
Proc Biol Sci. 2022 Oct 26;289(1985):20221073. doi: 10.1098/rspb.2022.1073. Epub 2022 Oct 19.
The host spectrum of viruses is quite diverse, as they can sustainedly infect a few species to several phyla. When confronted with a new host, a virus may even infect it and transmit sustainably in this new host, a process called 'viral spillover'. However, the risk of such events is difficult to quantify. As climate change is rapidly transforming environments, it is becoming critical to quantify the potential for spillovers. To address this issue, we resorted to a metagenomics approach and focused on two environments, soil and lake sediments from Lake Hazen, the largest High Arctic freshwater lake in the world. We used DNA and RNA sequencing to reconstruct the lake's virosphere in both its sediments and soils, as well as its range of eukaryotic hosts. We then estimated the spillover risk by measuring the congruence between the viral and the eukaryotic host phylogenetic trees, and show that spillover risk increases with runoff from glacier melt, a proxy for climate change. Should climate change also shift species range of potential viral vectors and reservoirs northwards, the High Arctic could become fertile ground for emerging pandemics.
病毒的宿主范围相当广泛，它们可以持续感染少数几个物种到几个门。当面对一个新宿主时，病毒甚至可能感染并在这个新宿主中持续传播，这个过程称为“病毒溢出”。然而，这种事件的风险很难量化。随着气候变化迅速改变环境，量化溢出的可能性变得至关重要。为了解决这个问题，我们采用了宏基因组学方法，重点研究了两个环境，即来自世界上最大的高北极淡水湖哈曾湖的土壤和湖底沉积物。我们使用 DNA 和 RNA 测序来重建湖泊的病毒圈，包括其沉积物和土壤中的病毒圈，以及其中真核宿主的范围。然后，我们通过测量病毒和真核宿主系统发育树之间的一致性来估计溢出风险，并表明溢出风险随着冰川融化的径流增加而增加，这是气候变化的一个指标。如果气候变化也使潜在病毒载体和宿主的物种范围向北转移，那么高北极地区可能成为新出现的大流行病的温床。
