(ORDO NEWS) — In a population of horseshoe bats living in karst caves in northern Laos, biologists have discovered three previously unknown types of coronaviruses.
“We conducted the first ‘census’ of coronaviruses affecting bat populations in northern Laos. We were able to identify five previously unknown pathogens, three of which, BANAL-52, BANAL-103 and BANAL-236, were close relatives of SARS-CoV-2. They are able to infect human cells,” the researchers write.
Due to the coronavirus pandemic, scientists around the world are investigating the history of the origin of SARS-CoV-2 and are looking for other dangerous animal coronaviruses that can infect humans. It turned out that similar pathogens circulate in populations of bats and other wild animals in Russia, the USA, Cambodia, Switzerland and other countries.
Biologists led by Marc Elois from the Pasteur Institute (France) in the course of a new study studied viruses that infect bats that live in karst caves on the border of China and Laos. This choice is explained by the fact that horseshoe bats Rhinolophus affinis live in similar conditions, which carry the RaTG13 virus – it is considered the closest relative of SARS-CoV-2.
Scientists caught more than 600 bats near such caves, collected samples of their blood and biofluids, and then tried to find RNA fragments and viable viral particles in them. In total, Elua and his colleagues found several dozen coronaviruses in these samples, including five previously unknown variations of these pathogens.
Biologists deciphered their genomes and found that the three viruses they discovered, named BANAL-52, BANAL-103 and BANAL-236, were very close to SARS-COV-2. The key part of the envelope of these pathogens did not differ much in structure from similar proteins of the COVID-19 pathogen. So the scientists tested whether the viruses they discovered could infect human cells.
Experiments with the BANAL-236 virus unexpectedly showed that it actively associated with the human version of the ACE2 protein, successfully penetrated into human cells and multiplied inside them. It was somewhat inferior to the COVID-19 pathogen in terms of reproduction rate, but at the same time it affected the same cell types as SARS-CoV-2. Two other viruses, according to the researchers, behave similarly.
The discovery of three new potentially dangerous coronaviruses, according to Elua and his colleagues, indicates that the alleged homeland of SARS-CoV-2 is indeed located in southern China or on its border with other countries in Southeast Asia. Further study of the viruses of local bats, as scientists hope, will allow us to better understand the history of the appearance of the pathogen COVID-19.
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