…before it finally acquired all the traits needed to cause this pandemic.
The long time spent in human to human transmission without causing much of an issue to its hosts would give the virus ample time for natural selection to work and the more virulent, lethal strain arise. It is also consistent with how other coronaviruses that bother humans have arisen.
So goes one of the hypotheses espoused in this article in Nature Medicine…which might provide another explanation why it arose in Wuhan besides a nefarious one where it came from a lab or from the wet market despite no bats being sold there.
If this hypothesis is true, we’ll never know where the animal to human jump took place, or whether there were several such jumps.