There are a couple cases of plague in the US every year, sometimes into the double digits, almost all in the west and southwest. It tends to happen here just like it happened to the man in China—through exposure to infected wildlife while hunting or exploring the outdoors. It is treatable with antibiotics like any other bacterial infection, and it is fatal only in a fairly small minority of US cases.
They therefore did NOTHING to stop it, and by the time they reluctantly took action, it was too late, it had spread from the city's rats to wild ground squirrels and from there to almost all the west and southwest.
Nothing stopping it from spreading all the way across flyover country to where important people live...
[[There are a couple cases of plague in the US every year,]]
Bubonic, pneumonic plagues- still around- still infecting people-
There’s another plague- Lyme Disease (and several lesser known ones from ticks too)- affecting millions-