PBS said that domesticated mice/rats don't have the same germs in their intestinal tract tht cause that disease Caroline. I dunno!
But that disease killed quite a few in the SouthWest on the Navajo reservation a few yrs ago as well as others that had somehow transferred the germs home from vacations around that area.
We've both had cats for most of our lives and the cats normally torment a mouse to death and then carry it around abit. Spit it out and walk away. We feed ours right so they don't want to eat a furry thing. lol