HUNDREDS of viruses lurking in animals could trigger the next killer pandemic, data has revealed.
SARS-CoV-2 is the latest virus to “spill over” from animals to humans and is believed to have originated from a wet market in Wuhan, China.
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Bats carry many coronaviruses but they are often not transmitted to humansCredit: Alamy
The main animal host of Covid-19 is thought to have been a bat, but experts have been unable to determine this and the virus is also known to have infected mink and lions.
A new tool called SpillOver, created by The University of California has ranked the newly discovered animal viruses that cause the greatest threat.
The researchers behind the tool said it could help scientists develop vaccines before a virus is able to spill over into the general population.
Zoë Grange, who led the development of SpillOver said: “SARS-CoV-2 is just one example of many thousands of viruses out there that have the potential to spill over from animals to humans.
“We need to not only identify, but also prioritise, viral threats with the greatest spillover risk before another devastating pandemic happens.”
HOW IT WORKS
The researchers created a credit-like score in order to determine how likely a virus would be to spill over to humans.
It uses 32 risk factors associated with a virus and its host.
This includes how often a human would interact with wild animals and how many different species of animal that the virus infects.
Around 250 viruses are known to be “zoonotic” and this means that they have already spilled over from animals to people.
But the researchers say there are some viruses that are not yet zoonotic – but could have the potential to be as dangerous as the ones above.
The graph above shows how the researchers use risk factors to determine whether or not a virus could create a pandemicCredit: PNAS
Coronavirus 229E, which belongs to the same family as Covid-19 infects bats in Africa is one of them along with a coronavirus called PREDICT (Cov-35), which also infects bats in Africa and South East Asia.
It’s estimated that over half a million other viruses have the potential to spillover from animals to humans.
The tool ranked the top three zoonotic viruses – and surprisingly Covid-19 is not at the top.
The top three are:
- Lassa virus
The Lassa virus comes from exposure to rodents in West Africa and symptoms can include fever, weakness and headaches, but most people who contract the virus don’t show any symptoms.
Covid-19 ranked second and the researchers said that this is because the tool calculates the potential for future spill over events and not how widespread the virus currently is.
Ebola is third and while scientists don’t know exactly where it originates from, they believe it could have been from a bat or primates such chimpanzees or apes.
The tool also ranked a whole host of other viruses that could be dangerous.
Many of the viruses come from different bat breeds, while some come from mice and rodents.
The tool shows how the risk score works and how many ranked viruses there areCredit: PNAS
Using the tool you are able to compare different coronaviruses.
You are also able to see how many species has the virus and whether or not it can be transmitted from human to human.
Study co-author Jonna Mazet, a professor at the UC Davis School of Veterinary Medicine said: “This tool is intended to start a global conversation that will allow us to go far beyond how we thought about ranking viruses in the past and allow real-time scientific collaboration to identify new threats early.
“SpillOver can help advance our understanding of viral health threats and enable us to act to reduce the risk of spillover before pandemics can catch fire.”