Plague comes in three forms from the same bacterium, bubunic, septacemic, and pnuemonic. The bubonic is caused by a fleabite and has all the horrible symptoms, swellings in the armpits and groin that go black. Pneumonic is when the epidemic runs rampant and enough bacteria is produced into the air that people get infected by inhaling it. This form kills so fast that there are no buboes(swellings). Victims of this form would have a fever a sneezing fit and die. There are large reservoirs of bubonic plague bacteria in native rodents in the western United States