[ansel12]

If they order a city quarantined (though this almost invariably happens too late)

When has that happened?

[yefragetuwrabrumuy]

In Europe, going way back. The reason is that before the quarantine, people get infected and invisibly spread the disease, but the quarantine only goes into effect once people start showing symptoms.

And all the other human vices come into play as well, from denial and delay in instituting the quarantine, breaking the quarantine either to flee or to smuggle goods, etc.

Several books document it as well. Daniel Defoe’s A Journal of the Plague Year, about the great plague of 1665.

Albert Camus, The Plague (1947).