Viral spillover risk increases with climate change in High Arctic lake sediments.

Background/Question/Methods

: The host spectrum of viruses is diversified, as it can range from a few species to several phyla. A virus may even infect a new host from a given reservoir, 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 and its range of eukaryotic hosts, and estimated the spillover risk by measuring the congruence between the viral and the eukaryotic host phylogenetic trees.

Results/Conclusions

: We show that spillover risk is higher in lake sediments than in soil, and increased 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.