Several research groups are focusing on the ACE2 receptor, a protein found on the surface of cells of many species. The spiked protrusions of the coronavirus allow it to bind to these receptors, like a key in a lock, and enter cells.
In 2020, a group of scientists compared ACE2 receptors of hundreds of vertebrate species, mainly mammals, with humans to identify infectious virus species. (The ACE2 receptors of birds, reptiles, fish, and amphibians are not homologous enough to ours to cause concern.)
“The predictions so far have been very good,” said Harris A. Lewin, a biologist at the University of California, Davis, and an author of the study. For example, scientists predict that white-tailed deer are at high risk of infection.
But some predictions have been proven wrong: The article identified domestic ferrets as a species of “very low concern” – and then in April 2020, the virus raging through mink farms.
Indeed, ACE2 only provides a snapshot of susceptibility. Kaitlin Sawatzki, a virologist at Tufts University, said: “Virus infection and immunity is much more complex than a virus attaching to a single cell.
And of the nearly 6,000 species of mammals in the world, scientists have sequenced the ACE2 receptors of just a few hundred of them, creating a skewed dataset. These sequenced species include the model organisms used in the experiments, other disease carriers, and charismatic zoo dwellers, not necessarily the animals that everyone easiest person to meet.
“If a pandemic came from a squirrel, we would say, ‘God, what’s wrong with us? Dr. Han said.