Fig. 1.

Representation of the conclusions from MacLean and colleagues according to the spillover and circulation models. The figure is adapted from MacLean et al., 2021 [1] and Frutos et al., 2021 [3]. The text in blue corresponds to the observations from MacLean et al., 2021 [1]. Arrows, viruses and text in red correspond to events involving SARS-CoV-2. Under the spillover model, the virus found in pangolins must come from another source than SARS-CoV-2. This is represented by the question mark. Under the circulation model, the species shown in the figure symbolize the circulation of the virus metapopulation in various animal species. They do not specifically represent species in which SARS-CoV-2 has been found.