Scientists have identified a new coronavirus in Brazilian bats which carries a key genetic feature also found in Sars-Cov-2, the pathogen that causes Covid-19.
The virus, called BRZ batCoV, was found in a ‘moustached’ species of bat common across much of Latin America. It’s likely that the pathogen has long been spreading unnoticed, as sampling in the region is limited.
Genetic sequencing of the virus – which was not isolated but studied digitally – shows it carries a furin cleavage site similar to that found in Sars-Cov-2.
This is the part of the Covid virus that allows it to unlock and enter human cells, and some questioned whether Sars-Cov-2 had been engineered in a laboratory because it had not been seen before.
But Dr Kosuke Takada, a co-author of the pre-print which has yet to be peer reviewed, said the discovery in Brazil “demonstrates that similar molecular features can arise independently in different viral lineages… through natural evolutionary processes”.
The work was done by the department of molecular virology at the University of Osaka, Japan.
Wildlife surveillance
Prof Stuart Neil, head of the department of infectious diseases at King’s College London who was not involved in the research, said this is not the first time that scientists have found furin cleavage sites similar to Sars-Cov-2 since the pandemic.
“We have very little idea about the selective pressures that promote the evolution of furin cleavage sites in bats or after cross species transmission. But what this paper reinforces is that they are not uncommon,” he said.
“While it doesn’t speak directly to how [Sars-Cov-2] got its furin cleavage site, it does show how easily they can pop up in the same part of a spike [protein] in very diverse viruses in the family.”
Prof David Robertson, head of bioinformatics the Centre for Virus Research at the University of Glasgow and also not involved in the study, said: “That they’ve found a furin cleavage site is interesting, but not unexpected given we know this region of the virus genome is relatively mutable.”
The researchers stressed that there is not yet any evidence that BRZ batCoV – which was found after they collected intestinal tissue samples from 70 bats in Brazil’s Maranhao and Sao Paulo states – can infect humans or other mammals.
Instead, the identification of these sorts of viruses in Latin America reaffirms the value of wildlife surveillance programmes, and holes in the current systems. Overall, most sampling has focused on Asia, Africa and the Middle East, where dangerous coronaviruses like Sars-1 and Mers first emerged.
“This study highlights that the potential for new pathogens to emerge is globally distributed, including in under-sampled regions like South America,” said Dr Takada, who is also a postdoctoral research associate at the University of Sydney.
“Still, detection does not equal danger – the real risk depends on ecological and human factors such as how often people come into contact with infected wildlife. By expanding our understanding of viral diversity in these regions, we can improve early warning systems and make more evidence-based assessments of which viruses warrant closer attention.”
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