In the latest study, researchers analysed partial sequences for some 1240 coronaviruses found in bats in China. They report that the virus fuelling the pandemic, SARS-CoV-2, is most closely related to a group of viruses found in horseshoe bats (Rhinolophus).

Their finding adds to an earlier report that a coronavirus called RATG13, which some of the authors found in intermediate horseshoe bats (Rhinolophus affinis) in Yunnan province, shares 96% of its genetic sequence with SARS-CoV-21.

The authors of the latest analysis note that the viral group to which both viruses belong seems to have originated in Yunnan province. But as the team only collected viruses from sites in China, they cannot rule out that a SARS-CoV-2 ancestor might have come from neighbouring Myanmar and Lao, where horseshoe bats also live.