An Australian team of researchers has published a new study which found that SARS-CoV-2, the virus which causes COVID-19, appears to be specifically adapted to attack human cells, according to the Daily Telegraph.
The scientists from Flinders University and La Trobe used powerful computers to model the protein receptors in a number of animal species to see how the coronavirus’s spike protein attached itself to them.
The theory was that if the coronavirus attached itself readily to an animal like a bat or a pangolin, it would have likely been the species that the bug used to make its leap into the human population.
However, the modelling found that the coronavirus’s spike protein was best suited to attacking protein receptors in humans.
"The computer modelling found the virus’s ability to bind to the bat ACE2 protein was poor relative to its ability to bind human cells," said Flinders University epidemiologist and vaccine researcher Professor Nikolai Petrovsky, adding "This argues against the virus being transmitted directly from bats to humans."
"Hence, if the virus has a natural source, it could only have come to humans via an intermediary species which has yet to be found."
Other animals found to be relative susceptible to infection include pangolins, dogs and cats - all of which have been ruled out as an intermediary species between bats and humans.
"Overall, putting aside the intriguing pangolin ACE2 results, our study showed that the COVID-19 virus was very well adapted to infect humans," Professor Petrovsky said.
The findings lend more weight to the lab-origin theory, which postulates that researchers at the Wuhan Institute of Virology became infected with SARS-CoV-2 and inadvertently spread the disease, or that it was intentionally released.
The Australian team's report, In silico comparison of SARS-CoV-2 spike protein-ACE2 binding affinities across species and implications for virus origin, can be found in the journal Scientific Reports.