A story appeared in the news some time back -- maybe a couple of years -- about a little girl who was hospitalized with high fever, vomiting, etc. The doctors treated her for septic shock, but she didn't improve, and blood tests didn't show anything.
Turns out, she had been camping in the woods with her family and had come in contact with a dead squirrel. When her doctor found out, she suspected plague and treated her accordingly. The little girl improved immediately and was able to go home a few days later.
It's odd how a disease once so common could become so rare that even trained doctors don't know to look for the signs.