What are “viral spillover risks”?

October 27, 2022

A new research found that climate change could increase the risk of “viral spillover” in several parts of the world. This could cause pandemics in the future.

Key facts

A new research article titled “Viral spillover risk increases with climate change in High Arctic lake sediments” was released recently.
Viral spillover occurs when viruses overcome several barriers to infect new host from reservoir host (in which it usually resides).
The researchers from the University of Ottawa sought to study the possibility of a viral spillover by collecting sediments and soil samples from Lake Hazen in Canada – the world’s largest High Arctic lake by volume.
High Arctic was chosen for this study since it is warming faster than the rest of the world.
The researchers sequenced the RNA and DNA to reconstruct the lake area’s virus composition and estimated the viral spillover risks.
The study found that the chances of viruses successfully infecting new host increases with the runoff from glacier melt.
With global warming increasing the instances of glacier melting, there is a high possibility of previously ice-trapped viruses and bacteria finding new hosts and increasing spillover risks.
Spillover risks are also increased due to changes in global distribution and dynamics of the viruses, their reservoirs and vectors.
However, this does not guarantee a higher possibility of pandemic occurring in the future.
This is because viral spillover depends on three main categories – pathogen pressure, human and vector behaviors and attributes of the host.
All these phases are fraught with several natural challenges that the virus must overcome to successfully reach the new host.
Coronaviruses successfully overcame these barriers since they are RNA viruses capable of evolving more quickly than other virus families because of their ability to recombine and acquire point mutations.
Other pathogens that have successfully spilled over to humans are Influenza A and Ebola.