Humans Pass More Viruses to Other Animals than We Catch from Them
Published:23 May2024    Source:University College London
Humans pass on more viruses to domestic and wild animals than we catch from them, according to a major new analysis of viral genomes by UCL researchers. The team analysed all publicly available viral genome sequences, to reconstruct where viruses have jumped from one host to infect another vertebrate species.
For the study, the research team developed and applied methodological tools to analyse the nearly 12 million viral genomes that have been deposited on public databases to date. The scientists found that roughly twice as many host jumps were inferred to be from humans to other animals (known as anthroponosis) rather than the other way round. This pattern was consistent throughout most viral families considered. Additionally, they found even more animal-to-animal host jumps, that did not involve humans.

The findings also show that, on average, viral host jumps are associated with an increase in genetic changes, or mutations in viruses, relative to their continued evolution alongside just one host animal, reflecting how viruses must adapt to better exploit their new hosts. Further, viruses that already infect many different animals show weaker signals of this adaptive process, suggesting that viruses with broader host ranges may possess traits that make them inherently more capable of infecting a diverse range of hosts, whereas other viruses may require more extensive adaptations to infect a new host species.