Patrick Burns offers a long entry on bubonic plague and its history in the United States. National Park Service employees probably should not read this entry unless they are feeling strong.
I never know whether to worry more about plague or about hantavirus. Right now, those foxes might be keeping the deer mouse population low. I have trapped only half a dozen in the garage (which gives entry to the basement)this fall, a low figure compared to some year.
The foxes, meanwhile, are leaving scat all around the house, to the point where you have to look where you step when you go outdoors. They love to come at dusk, when the dogs are penned on the front porch before supper, and taunt them.
It's the price you pay for mouse control.