COVID 19: Time to exonerate the pangolin from the transmission of SARS CoV 2 to humans
Abstract The emergence of COVID 19 has triggered many works aiming at identifying the animal intermediate potentially involved in the transmission of SARS CoV 2 to humans. The presence of SARS CoV 2 related viruses in Malayan pangolins, in silico analysis of the ACE2 receptor polymorphism and sequence similarities between the Receptor Binding Domain (RBD) of the spike proteins of pangolin and human Sarbecoviruses led to the proposal of pangolin as intermediary. However, the binding affinity of the pangolin ACE2 receptor for SARS CoV 2 RBD was later on reported to be low. Here, we provide evidence that the pangolin is not the intermediate animal at the origin of the human pandemic. Moreover, data available do not fit with the spillover model currently proposed for zoonotic emergence which is thus unlikely to account for this outbreak. We propose a different model to explain how SARS CoV 2 related coronaviruses could have circulated in different species, including humans, before the emergence of COVID 19.
Infection, Genetics and Evolution