Some research teams are focusing their attention on the ACE2 receptor. This protein is found on the cells of many species’ surfaces. The coronavirus’s spiky protrusions allow it to bind to these receptors, like a key in a lock, and enter cells.
A group of scientists compared the ACE2 responses of hundreds of vertebrates (mostly mammals) with those of humans in 2020 to determine which species the virus could infect. (The ACE2 receptors in birds, reptiles and fish are not comparable enough to ours to cause concern.
“The predictions have been very good so far,” Harris A. Lewin, a biologist at the University of California, Davis, and an author of the study, said in an email. For instance, the scientists predicted that white-tailed deer would be at high risk of infection.
But some predictions proved entirely wrong: The paper identified farmed mink as a species of “very low” concern — and then in April 2020 the virus raged through mink farms.
ACE2 provides only a snapshot into susceptibility. “Viral infection and immunity is much more complex than just a virus binding to a cell,” Kaitlin Sawatzki, a virologist at Tufts University, said in an email.
And of the world’s nearly 6,000 mammalian species, scientists have sequenced the ACE2 receptors of just a few hundred of them, creating a biased data set. These sequenced species include models organisms that are used in experiments, species with other diseases, charismatic zoo denizens, and not necessarily the animals people are most likely encounter.
“If a pandemic were to have arisen from a squirrel, we would be like, ‘God, what’s wrong with us? We didn’t even measure the basic biology of a squirrel,’” Dr. Han said.
Source: NY Times