Bats dwelling in limestone caves in northern Laos were found to carry coronaviruses that share a key feature with SARS-CoV-2, moving scientists closer to pinpointing the cause of Covid-19.
Researchers at France’s Pasteur Institute and the University of Laos looked for viruses similar to the one that causes Covid among hundreds of horseshoe bats. They found three with closely matched receptor binding domains — the part of the coronavirus’s spike protein used to bind to human ACE-2, the enzyme it targets to cause an infection.
The finding, reported in a paper released Friday that’s under consideration for publication by a Nature journal, shows that viruses closely related to SARS-CoV-2 exist in nature, including in several Rhinolophus, or horseshoe bat, species. The research supports the hypothesis that the pandemic began from a spillover of a bat-borne virus. . . .
The three viruses found in Laos, dubbed BANAL-52, BANAL-103, and BANAL-236, are “the closest ancestors of SARS-CoV-2 known to date,” said Marc Eloit, head of pathogen discovery at the Pasteur Institute in Paris, and co-authors. “These viruses may have contributed to SARS-CoV-2’s origin and may intrinsically pose a future risk of direct transmission to humans.”
Note that this newly discovered virus is still significantly different from SARS-CoV-2. But the finding is still important, as the receptor binding domains (RBDs) are pretty similar, and some lab leak proponents had argued that the SARS-CoV-2 RBD was suspicious and likely a product of “gain of function” research.