Viruses from the coronavirus lineage accountable for COVID-19 have been circulating in bats for many years, lengthy earlier than the virus began infecting folks final yr, a brand new research suggests.
How precisely the virus jumped to people continues to be a thriller. However the research suggests the coronavirus most definitely developed in bats — corresponding to intermediate horseshoe bats (Rhinolophus affinis), the supply of the coronavirus that induced the 2003–2004 SARS outbreak — not snakes or pangolins as some researchers have steered (SN: 1/24/20). Pangolins or one other animal would possibly nonetheless have been an intermediate host earlier than the virus made it to people.
Maciej Boni, an epidemiologist at Penn State, and his colleagues examined the genetic blueprints of the brand new coronavirus, or SARS-CoV-2, and 67 associated viruses. The evaluation aimed to uncover the evolutionary historical past of SARS-CoV-2 and see if the virus had exchanged bits of genetic materials with different coronaviruses, a course of referred to as recombination, to develop into the formidable pathogen it’s now.
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SARS-CoV-2 will not be the results of genetic shuffling amongst recognized coronaviruses, the researchers report July 28 in Nature Microbiology. Earlier research had steered that recombination with coronaviruses from pangolins could have contributed a portion of the virus’ spike protein, which is used to interrupt into human cells (SN: 3/26/20). However the spike’s capacity to connect to a protein on host cells referred to as ACE2, which permits the virus to achieve entry, seems to be an ancestral trait, moderately than one gained from recombination.
Primarily based on the evolutionary relationship among the many 68 coronaviruses, the researchers estimate that the department of the virus household tree that results in SARS-CoV-2 diverged from associated viruses between 1948 and 1982. These dates counsel that the coronavirus lineage that gave rise to the virus behind the pandemic has been current in bats for many years.
That lengthy interval hints that extra bat viruses with the potential to contaminate people are circulating in horseshoe bats. Looking for such bat viruses may also help establish potential threats earlier than the pathogens make the bounce, the staff writes.