Rethinking Virus Transmission: Humans as Vectors to Animals
In a paradigm-shifting revelation, researchers from the University College London challenge the conventional belief that animals are the primary source of infectious diseases transmitted to humans. Instead, their analysis of viral genomes suggests that humans frequently spread viruses to both wild and domestic animals, significantly increasing the risk of disease transmission among animal populations.
Lead author Cedric Tan, a doctoral student at UCL’s Genetics Institute and Francis Crick Institute, emphasizes the implications of human-to-animal virus transmission. Not only does this phenomenon pose a threat to animal health and conservation efforts, but it also has potential ramifications for human health and food security. The recent outbreaks of diseases like the H5N1 bird flu, where large-scale culling of livestock was necessary to prevent epidemics, serve as stark examples of the consequences of such transmission.
Published in the journal Nature Ecology and Evolution, the study utilizes advanced methodological tools to analyze nearly 12 million viral genomes. By reconstructing the evolutionary histories and past host jumps of viruses across various families, the researchers shed light on the prevalence of human-to-animal transmission. Surprisingly, they find that humans are twice as likely to transmit viruses to animals (anthroponosis) compared to the reverse scenario. This underscores the need to reconsider humans not as mere recipients but active contributors to the spread of infectious diseases across species boundaries.
Co-author Professor Francois Balloux from UCL Genetics Institute highlights the significance of viewing humans as integral nodes within a broader network of hosts exchanging pathogens. This shift in perspective opens new avenues for understanding viral evolution and emergence, crucial for mitigating the risks of future pandemics both in humans and animals.
