"While ACE2 receptor amino acid sequences in different animals show phylogenetic distance with respect to the human ACE2 receptor, the pangolin, cat, feline, and dog ACE2 receptor sequences cluster closely (Figure 1), and it predicts that the S protein of SARS-CoV-2 may bind to ACE2 in domestic cats and dogs, as well as a range of other species, including pigs, cows, pangolins, and Chinese hamsters"
"ADE modulates the immune response and can trigger violent immune reactions such as the cytokine storm, directly related to severe COVID-19 cases and deaths [7]. This phenomenon requires prior exposure to similar antigenic epitopes, and some animal species, such as dogs, pigs, and bovines, are often infected by taxonomically related coronaviruses [9,10]. Consequently, past interrelation with animals previously infected with animal coronaviruses might have primed the human immune system against them and, in turn, conferred a partial protection against the circulating SARS-CoV-2 [8,9,10], this being a possible explanation for the observed geographic limitation of severe cases and deaths."
