For years, scientists have warned that the next pandemic threat could come from humans contracting infections from animals.
But now a study suggests the opposite is actually more likely.
Humanity passes on more viruses to animals than we contract from them, say researchers at University College London.
Experts said “people are both a source and a sink” for viral health crises.
UCL co-author Professor Francois Balloux said: ‘We should think of humans as one node in a vast network of hosts endlessly exchanging pathogens, rather than a sink for zoonotic insects.
Humanity passes on more viruses to animals than we contract from them, say researchers at University College London. Experts said “people are both a source and a sink” for viral health crises. Pictured is a brown long-eared bat in Sussex
UCL researchers analyzed tens of thousands of viral genomes in public databases. This allowed experts to look at all the information hidden in a virus, including where the virus jumped across a species. This allowed the team to determine whether such pathogens passed from humans to animals (anthroponosis) or the other way around (zoonosis). They found that almost two-thirds (64 percent) of the samples they analyzed were transmitted from humans to animals
‘By investigating and monitoring the transmission of viruses between animals and humans, in both directions, we can better understand viral evolution.’
He said this could “hopefully” enable society to be “better prepared for future outbreaks and epidemics of new diseases.”
Concerns about zoonotic diseases such as Ebola, which spread from animals to humans, and their potential to cause pandemics have been growing for some time.
However, human-to-animal transmission has received “little attention,” researchers wrote in the journal Nature ecology and evolution.
UCL researchers analyzed tens of thousands of viral genomes in public databases.
This allowed experts to look at all the information hidden in a virus, including where the virus jumped across a species.
This allowed the team to determine whether such pathogens passed from humans to animals (anthroponosis) or the other way around (zoonosis).
They found that almost two-thirds (64 percent) of the samples they analyzed were transmitted from humans to animals.
Lead author Dr Cedric Tan warned that human-borne viruses ‘could potentially pose a threat to the conservation of the species’.
He added: ‘It could also create new problems for humans by affecting food safety if large numbers of livestock have to be culled to prevent an epidemic, as has happened in recent years with the H5N1 bird flu.
“Moreover, if a human-borne virus infects a new species, the virus may continue to thrive even if it is eradicated from humans.”
Dr. Tan warned that it “could even develop new adaptations before eventually infecting humans again.”
He added: ‘Understanding how and why viruses evolve to jump into different hosts in the wider tree of life can help us figure out how new viral diseases arise in humans and animals.’
Some believe Covid jumped from bats in China to humans – possibly via an intermediate species such as raccoon dog or pangolin.
Scientists have largely pointed to the Huanan wholesale seafood market in Wuhan (pictured), where numerous species of live animals were raised and sold, as the potential location where Covid naturally spread from animals to humans.
It has been suggested that Covid was bioengineered at the Wuhan Institute of Virology (pictured) in central China, which specializes in studying coronaviruses
The WHO’s initial study in January 2021, in which a group of scientists traveled to Wuhan, concluded that “all hypotheses are still on the table.” In its March 2021 report, it ranked the likelihood of four theories, with the natural origins theory considered the most likely. But it put the lab leak an “extremely unlikely path” behind the frozen food origin story
Others believe a lab leak is the cause of the pandemic.
China has repeatedly insisted that one of its wet markets, in Covid’s ‘ground zero’ Wuhan, was the source of the pandemic.
Scientists have largely pointed to the Huanan wholesale seafood market in Wuhan, where numerous species of live animals were raised and sold, as the potential location where the virus naturally spread from animals to humans.
Many of the first cases in December 2019 and January 2020 had visited the location where live animals were sold.
But Beijing has also been repeatedly accused of cover-ups and stifling efforts to investigate a laboratory Wuhan that experimented with similar viruses months before the disease emerged in the city.
However, no concrete evidence has been found to support Covid origin arguments, leading experts to fear that the truth behind the virus’s origins may never be discovered.