Although rare, the plague, yersinia pestis, can and still does affect people in the US each year. According to CBS News, the most recent case just occurred in Larimer County, Colorado, and took the life of a 16 year old male. The CDC says that the plague is typically spread by infected fleas who can then spread the disease to humans. There are approximately 7 cases each year in the US that occur mostly in western states. There is currently an antibiotic for the plague, but since symptoms can initially resemble the flu, it is often not caught early enough at a time when it can still be treated.