The Black Death was caused by a bacteria called Yersinia pestis. The way the plague originally spread was through flea bites. Yersinia pestis was found in the stomach of fleas that lived on wild rats. Fleas would bite the wild rats and infect them. When the wild rats and fleas traveled on ships to other countries, they came in contact with city rodents and humans, who they infected. The disease rapidly spread because cities were areas of dense population and humans were in close contact with infected rodents and each other. Humans were bit or got infected by handling dead animals that died from the plague. Also, when people were close to dying, they could spread the disease to each other through their cough or body fluids.
When in the body, Yersinia pestis drained toward lymph nodes, which are located under the armpits, behind the ears and neck, and in the groin region. Then the Yersinia pestis would reproduce at a rapid rate and swell the nodes. When the nodes close to the skin would swell, they would form dark buboes, an indication that the organs and blood stream had been infected.
"It was of two kinds; the first lasted two months, with constant fever and blood-spitting, and of this people died in three days. The second lasted for the rest of the time. In this, together with constant fever, there were external carbuncles, or buboes, under the arm or in the groin, and the disease ran its course in five days."
-Guy De Chauliac: On the Black Death at Avignon (1348)
3 Types of the plague
- Bubonic, Pheumonic, and Septicemic
Symptoms of the plague
- Bubonic – Fever, chills, enlarged, painful lymph nodes (called buboes) in groin, arm pit, neck. If this is not treated, it can progress to pneumonic and/or septicemic plague.
- Pneumonic – Fever, pneumonia (shortness of breath, cough, chest pain)
- Septicemic – Fever, chills, abdominal pain, low blood pressure, bleeding into skin and organs. The hands and feet can turn black.
- Pre-antibiotic age (prior to 1940’s)- no effective treatments were known
- Antibiotic age – Gentamicin, doxycycline (antibiotics)
- Pre-antibiotic age
- Bubonic plague – 65-75%
- Pneumonic plague – 95-100%
- Septicemic plague – 100%
- Antibiotic age – 11% in USA (http://www.cdc.gov/plague/faq/)
- Because the cause and spread of plague was not known, proper precautions could not be implemented so it spread rapidly and killed millions of people.
“A person wearing a hat, a mask suggestive of a bird beak, goggles or glasses, and a long gown. The clothing identifies the person as a "plague doctor" and is intended as protection. Descriptions indicate that the gown was made from heavy fabric or leather and was usually waxed. The beak contained pungent substances like herbs or perfumes, thought at the time to purify the air and helpful in relieving the stench. The person also carries a pointer or rod to keep patients at a distance. (Library of Medicine)” (http://www.cdc.gov/plague)
"No doctor's advice,
Boccaccio, Giovanni, The Decameron