Thanks to adaptive immunity infected cells get wiped out, and exposure to a specific pathogen can leave us with long-standing protection against that pathogen.

If we wiped that out, would the angel give us what we want?

On the first day of class, he gave us a lecture about an animal called the Cattywampus, an ill-adapted nocturnal animal that was wiped out during the Ice Age, he passed around a skull as he talked.