| The Black Death 1347 - 1350 Culprit: Oriental Rat Flea
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Family: Pulicidae Order: Siphonaptera Genus: Xenopsylla Species: cheopis Dead littered the streets everywhere. Cattle and livestock roamed the country unattended. Brother deserted brother. The Black Death was one of the worst natural disasters in history. In 1347 A.D., a great plague swept over Europe, ravaged cities causing widespread hysteria and death. One third of the population of Europe died. "The impact upon the future of England was greater than upon any other European country." (Cartwright, 1991) The primary culprits in transmitting this disease were oriental rat fleas carried on the back of black rats.

Frederick F. Cartwright, DISEASE AND HISTORY, Dorset Press, New York, 1991, p. 42.

Written by: Melissa Loftus, Alex Sherman, Ashley Quan, and Mieko Griffin |

How it was Transmitted

How was the Black Death transmitted? The three forms of the Black Death were transmitted two ways. The septicemic and bubonic plague were transmitted with direct contact with a flea, while the pneumonic plague was transmitted through airborne droplets of saliva coughed up by bubonic or septicemic infected humans. The bubonic and septicemic plague were transmitted by the the bite of an infected flea. Fleas, humans, and rats served as hosts for the disease. The bacteria (Yersinia pestis) multiplied inside the flea blocking the flea's stomach causing it to be very hungry. The flea would then start voraciously biting a host. Since the feeding tube to the stomach was blocked , the flea was unable to satisfy its hunger. As a result, it continued to feed in a frenzy. During the feeding process, infected blood carrying the plague bacteria , flowed into the human's wound. The plague bacteria now had a new host. The flea soon starved to death. The pneumonic plague was transmitted differently than the other two forms . It was transmitted through droplets sprayed from the lungs and mouth of an infected person. In the droplets were the bacteria that caused the plague. The bacteria entered the lungs through the windpipe and started attacking the lungs and throat. |

The Black Death The Black Death came in three forms, the bubonic, pneumonic, and septicemic. Each different form of plague killed people in a vicious way. All forms were caused by a bacterium called Yersinia pestis. The bubonic plague was the most commonly seen form of the Black Death. The mortality rate was 30-75%. The symptoms were enlarged and inflamed lymph nodes (around arm pits, neck and groin). The term 'bubonic' refers to the characteristic bubo or enlarged lymphatic gland. Victims were subject to headaches, nausea, aching joints, fever of 101-105 degrees, vomiting, and a general feeling of illness. Symptoms took from 1-7 days to appear. The pneumonic plague was the second most commonly seen form of the Black Death. The pneumonic and the septicemic plague were probably seen less then the bubonic plague because the victims often died before they could reach other places (this was caused by the inefficiency of transportation). The mortality rate for the pneumonic plague was 90-95% (if treated today the mortality rate would be 5-10%). The pneumonic plague infected the lungs. Symptoms included slimy sputum tinted with blood. Sputum is saliva mixed with mucus exerted from the respiratory system. As the disease progressed, the sputum became free flowing and bright red. Symptoms took 1-7 days to appear. The septicemic plague was the most rare form of all. The mortality was close to 100% (even today there is no treatment). Symptoms were a high fever and skin turning deep shades of purple due to DIC (disseminated intravascular coagulation). According to Dr. Matt Luther, Vanderbilt University Medical Center "The plague often caused DIC in severe forms, and DIC can be fatal. The picture above demonstrates