Assuming that you are not dealing with a weaponized, antibiotic resistent strain, you can treat the infection with antibiotics.
From a Plague Q&A website: Q. What is the incubation period for plague?
A. A person usually becomes ill with bubonic plague 2 to 6 days after being infected. When bubonic plague is left untreated, plague bacteria invade the bloodstream. When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition. Infection of the lungs with the plague bacterium causes the pneumonic form of plague, a severe respiratory illness. The infected person may experience high fever, chills, cough, and breathing difficulty, and expel bloody sputum. If plague patients are not given specific antibiotic therapy, the disease can progress rapidly to death.
The point I was trying to address is that with this form of bioterrorism, people may believe the problem to be a bad respiratory infection and let it go to the very last minute before they seek medical attention.