Most people have heard of the Black Death, also known as the Bubonic Plague. There were actually 3 plagues, the Bubonic, which infected the lymph nodes, the Pneumonic, which infected the lungs, and the most deadly of all, the Septicemic Plague which infected the blood and had a mortality rate of nearly 100%.

There were many signs and symptoms of the 3 plagues, including the appearance of buboes (swelling of the lymph nodes) in the groin, neck and armpits in the Bubonic Plague. These buboes would bleed and ooze puss. When fatal, the victim was usually dead in 4-7 days.

It was commonly assumed that the disease was spread by rats which had been infected by fleas, but some scientists and historians have challenged all that was previously believed to be true, and have the theory that the disease was actually a viral fever. Regardless, the deadly results are known, although the exact numbers can never be documented, it is estimated that at least a third of the population of Europe, and up to 60% of all Europeans were killed by the pandemic in the 1340s. The entire population of the world was about 450 million people, which was reduced to an estimated 350-375 million by about 1400.

The term Black Death was not used until the 1600s to describe the outbreak, although many thought it was called that during the pandemic because of the blackening of the skin, and also the extremities (from gangrene). It was commonly known as The Great Plague, The Great Mortality or The Great Pestilence by those living during the period.

It's isn't as widely known, but the plague is believed to have returned during every generation in Europe until the 1700s, with varying virulence. An estimated 100 plague outbreaks occurred during this period.

Could something like this happen again though ? Yes, the infection(s) may be different, but with what we know presently about just some of the viruses (that are known) and their ability to evolve, to become resistant to our most effective antibiotics, would suggest that a wide-spread pandemic should almost be expected. The present H1N1 outbreak comes to mind. Even though it was from a known virus, we still had to scramble to come up with a vaccine. Many people died worldwide by the time the vaccine was ready. What would have been the results if this was a new virus, one that we had no defenses against ?

One such virus, the Ebola virus, which causes Ebola Hemorrhagic Fever is but one example of a known virus that we have no standard treatment for, with patients receiving only "supportive therapy." The exact origin, and natural habitat of the Ebola Virus are not even known at this point, and this is a virus that has been known since 1976, and has killed many. To believe that there are not many other similar viruses out there, or others evolving into what may be the next Ebola would be wishful thinking.

Although mankind is never lacking in his attempts to kill off the human population, it just may be an unseen, unknown culprit that finally rids the earth of humans.