By Helen Briggs, BBC Environment correspondent
Scientists say coronaviruses related to Sars-CoV-2 may be circulating in bats across many parts of Asia.
A virus that is a close match to the Sars-CoV-2 virus, which causes Covid-19, has been discovered in bats at a wildlife sanctuary in eastern Thailand.
The researchers predict that related coronaviruses may be present in bats across many Asian nations and regions.
Their discovery extends the area in which related viruses have been found to a distance of 4,800km (2,983 miles).
The study is reported in Nature Communications.
Writing in the journal, the researchers said the sampling site (Thailand only) and sampling size was limited, but they were confident 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”.
Past studies have suggested that Sars-CoV-2 emerged in an animal, most likely a bat, before spreading to humans.
The precise origins of the virus are unknown and have been investigated by a team commissioned by the World Health Organization (WHO).
In the latest research, a team lead by Lin-Fa Wang of the University of Singapore detected a close relative of Sars-CoV-2 in horseshoe bats kept in an artificial cave at a wildlife sanctuary in Thailand.
The isolated virus, named RacCS203, is a close match to the genetic code of SARS-CoV-2 (exhibiting 91.5% similarity in their genomes).
It is also closely related to another coronavirus – called RmYN02 – which is found in bats in Yunnan, China and which shows 93.6% similarity to the genome of Sars-CoV-2.
The researchers, from Thailand, Singapore, China, Australia and the US, looked at antibodies in the bats and in a trafficked pangolin in southern Thailand.
