Two lab freezers in Asia have yielded surprising discoveries. Researchers have told Nature they have found a coronavirus that is closely related to SARS-CoV-2, the virus responsible for the pandemic, in horseshoe bats stored in a freezer in Cambodia. Meanwhile, a team in Japan has reported the discovery of another closely related coronavirus — also found in frozen bat droppings.

The viruses are the first known relatives of SARS-CoV-2 to be found outside China, which supports the World Health Organization’s search across Asia for the pandemic’s animal origin. Strong evidence suggests that SARS-CoV-2 originated in horseshoe bats

https://www.nature.com/articles/d41586-020-03217-0

The virus in Cambodia was found in two Shamel’s horseshoe bats (Rhinolophus shameli) captured in the country’s north in 2010. The virus’s genome has not yet been fully sequenced — nor its discovery published — making its full significance to the pandemic hard to ascertain.

If the virus is very closely related to — or even an ancestor of — the pandemic virus, it could provide crucial information about how SARS-CoV-2 passed from bats to people, and inform the search for the pandemic’s origin, says Veasna Duong, a virologist at the Pasteur Institute in Cambodia in Phnom Penh, who led the search of the old samples in Cambodia and alerted Nature to the discovery in early November. To provide such insights, the virus would have to share more than 97% of its genome with SARS-CoV-2, which is more than its closest known relative, say researchers.

But the new virus might be more distantly related, in which case, studying it will help scientists to learn more about the diversity in this virus family, says Etienne Simon-Loriere, a virologist at the Pasteur Institute in Paris, who plans to sequence the virus, after which it will be shared publicly.

That is the case with the other virus, called Rc-o319, identified in a little Japanese horseshoe bat (Rhinolophus cornutus) captured in 2013. That virus shares 81% of its genome with SARS-CoV-2, according to a paper1 published on 2 November — which makes it too distant to provide insights into the pandemic’s origin, says Edward Holmes, a virologist at the University of Sydney in Australia.