Plague
Plague is a bacterial disease caused by Yersinia pestis, carried by wild rodents such as prairie dogs and ground squirrels and spread to people mainly by the bites of their fleas. It takes three forms: bubonic, with swollen and painful lymph nodes; septicemic, in the blood; and pneumonic, in the lungs, the only form that passes from person to person through the air.
Preppers meet plague because it never disappeared. It is rare, a handful of US cases a year in the rural West, but it lives on in the animals around campgrounds, trails and ranches, and pets can carry infected fleas indoors. Common antibiotics cure it when treatment starts early, which is why telling a doctor about outdoor exposure in plague country matters.
Plague is one of several diseases that can start an outbreak. For the terms that describe how far a disease has spread, start with the difference between an outbreak and an epidemic.
