30 Mar 2020
Researchers identify protein sequences in lungs of sick pangolins that were 91% identical to the human virus’ proteins.
David Woodmansey
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Image © 2630ben / Adobe Stock
New evidence points to the pangolin – a type of scaly anteater – as the most likely intermediate host for the new coronavirus, researchers say.
A study in the American Chemical Society’s Journal of Proteome Research analysing DNA evidence suggests pangolins are the missing link for SARS-CoV-2 transmission between bats and humans.
Most experts agree that bats are a natural reservoir of SARS-CoV-2, but an intermediate host was needed for it to jump from bats to humans. It had been theorised that snakes might have been that intermediate host.
Further work employing larger data sets and newer, more accurate bioinformatics methods and databases to analyse the SARS-CoV-2 genome has now taken place.
After uncovering an error in the analysis that suggested snakes as an intermediate host, the team searched DNA and protein sequences isolated from pangolin tissues for ones similar to SARS-CoV-2.
The researchers identified protein sequences in sick animals’ lungs that were 91% identical to the human virus’ proteins. Moreover, the receptor-binding domain of the spike protein from the pangolin coronavirus had only five amino acid differences from SARS-CoV-2, compared with 19 differences between the human and bat viral proteins.
This evidence points to the pangolin as the most likely intermediate host for the new coronavirus, but additional intermediate hosts could be possible, the researchers say.
The pangolin is one of the most critically endangered species on the planet. It is the most trafficked animal in the world, with its scales highly sought in traditional Chinese medicine.
