Medieval physicians and chroniclers observed with horrified accuracy a panoply of symptoms, not realizing that they were witnessing different forms of the same illness. The most common form, called bubonic, is characterized by the formation of egg-sized swellings at the site of an infected flea bite, usually located in the armpits, groin or neck. Acute agonizing pain accompanies these growths. Next, hemorrhaging under the skin occurs, causing purplish blotches that frequently encircle the waist. Victims of bubonic plague die within four to six days of contraction.

Person to Person
A second form, pneumonic plague, occurs when the infection moves into the lungs, allowing the bacteria to be transmitted easily from person to person. A cough, a sneeze or the mere act of breathing sends death into the air. Symptoms include the vomiting of blood.

In septicemia, the third type of plague, massive numbers of the bacilli enter the bloodstream. A victim's body virtually explodes with the disease. A rash appears within hours, and death occurs within a day, even before buboes have time to appear.

Whatever form a victim contracted, everything about the plague was disgusting, so that the sick became objects of revulsion rather than of pity. All matter that exuded from their bodies let off an unbearable stench; sweat, excrement, spittle, and breath became so foul as to be overpowering; urine could be turbid, thick, black or red. All diseases have their own methods for creating misery, but this plague brought with it a unique ability to degrade, disgust and destroy its victims.