SARS-CoV-2-related coronaviruses are circulating in wildlife across Southeast Asia. This finding stemmed from a study of bats and pangolins in Thailand.
Published in Nature Communications, the international team of researchers led by Duke-NUS experts found that 13 out of the 100 horseshoe bats studied tested positive for these SARS-CoV-2-like coronaviruses. These positive results all contained a particular genetic sequence that is 95.86 per cent identical to the corresponding section in human SARS-CoV-2, 96.21 and 94.48 per cent identical to the bat-borne CoV-RaTG13 and CoVRmYN02 viruses, respectively.
When testing for past infections using the Duke-NUS-invented surrogate virus neutralisation test cPass™, the team further found that one of ten pangolin serum samples screened showed a strong surrogate virus neutralisation test (sVNT) reading, exceeding 90 per cent. This corroborated published findings that pangolins are susceptible to infection by such viruses.
The research team, which included Professor Wang Linfa, then-Senior Research Fellows Drs Tan Chee Wah and Chia Wan Ni from the Emerging Infectious Diseases Programme at Duke-NUS, was confident that this finding demonstrates that coronaviruses with a high degree of genetic relatedness to SARS-CoV-2 are widely present in bats across many nations and regions in Asia.
The team also observed that these coronaviruses have been detected in bats across an area of approximately 4,800km, spanning from Iwata Prefecture in Japan in the north and Zhejiang province in China in the east to Yunnan in the southwest of China and southward in Chachoengsao, Thailand.
The great genetic diversity and plasticity of these viral genomes suggested to the team that the immediate progenitor virus of SARS-CoV-2 could be, with intensified and internationally coordinated surveillance, traceable.