In the case of SARS-CoV, civets, ferrets, and raccoon dogs were identified as replicative hosts, with ≥7 amino acid substitutions observed in their respective isoforms of ACE2 compared to other infection-permissive species, suggesting that SARS-CoV seems to “tolerate” large variations in the receptor (7, 14, –, 16). The gene discussed is ACE2; the disease is infection.