Originally Posted by wikipedia
Signs and symptoms
Bubonic plague
Symptoms of the disease include fever of 38–41 °C (100–106 °F), headaches, painful aching joints, nausea and vomiting, and a general feeling of malaise. Left untreated, of those that contract the bubonic plague, 80 percent die within eight days.
Contemporary accounts of the pandemic are varied and often imprecise. The most commonly noted symptom was the appearance of buboes (or gavocciolos) in the groin, neck, and armpits, which oozed pus and bled when opened.
Boccaccio's description:
In men and women alike it first betrayed itself by the emergence of certain tumours in the groin or armpits, some of which grew as large as a common apple, others as an egg ... From the two said parts of the body this deadly gavocciolo soon began to propagate and spread itself in all directions indifferently; after which the form of the malady began to change, black spots or livid making their appearance in many cases on the arm or the thigh or elsewhere, now few and large, now minute and numerous. As the gavocciolo had been and still was an infallible token of approaching death, such also were these spots on whomsoever they showed themselves.
This was followed by acute fever and vomiting of blood. Most victims died two to seven days after initial infection.