This is significant because it demonstrates the potential for existing viruses to swap bits of their genetic code – a process known as recombination – to form new pathogens.
“The main take-home message is that individual bats can harbour a plethora of different virus species, occasionally playing host to them at the same time,” said Prof Jonathan Ball, a virologist at the University of Nottingham who was not involved in the research.
“Such co-infections, especially with related viruses like coronavirus, give the virus opportunity to swap critical pieces of genetic information, naturally giving rise to new variants,” he said.
‘Clear and present threat’
Professor Stuart Neil, head of the department of infectious diseases at King’s College London, added: “This study gives us a very important snapshot into the evolution and ecology of [coronaviruses], the scope for them to recombine and skip into new species regularly.”
It shows a “clear and present threat of new spillovers to humans,” he added.
Previously, analysis has estimated that as many as 400,000 people are infected by viruses carried by bats every year across southern China and southeast Asia.
Of the five viruses labelled “viruses of concern”, one – known as BtSY2 – had characteristics of both Sars, a virus which killed 774 people and infected 8,000 in an outbreak in 2003, and Sars-Cov-2, which causes Covid-19 disease.
Of note, BtSY2 had a receptor binding domain – the part of the spike protein that it uses to latch onto human cells, which most Covid-19 vaccines target – very similar to Sars-Cov-2, possibly closest seen in animal viruses to date. This suggests BtSY2 may also be able to infect humans.