
2. Bubonic Plague
It’s nearly impossible to believe that fleas found in ground rodents brought death to humans by the millions. Well believe it, because they were the perpetrator behind The Black Death and several other plagues. These fleas carried Yersinia pestis, bacteria that was natural to them but was deadly to humans
What makes the bubonic plague scary is how it initially attacks the lymphatic system which plays a major role in a person’s immunity. Within 3 to 7 days after infection, you will develop high fever, gangrene of the extremities, chills, seizures, and muscle cramps. Symptoms like heavy breathing, vomiting of blood, painful limbs, and skin necrosis will set in later. Eventually, you will be delirious, fall into a coma, and die.

The disease was first recorded in 6th century Byzantine Empire as the Plague of Justinian, killing 50 million people in the Roman Empire. It caused the most deaths when it hit Europe during the Late Middle Ages from 1340 to 1400. By then it was called The Black Death, the deadliest disease in human history. The bubonic plague continued to claim lives in Europe until the Great Plague of Marseilles in 1720.
Another outbreak reappeared in the mid-19th century and killed 12.5 million people in India before spreading to Hawaii and Australia. The pandemic ended in 1959. After that, deaths caused by Y. pestis dropped to 200 a year. While a small outbreak occurred in India at 1994, only 52 died out of the 700 infected.