Believe it or not, the Black Death, which is responsible for killing somewhere around 75 million to 200 million people in the mid-fourteenth century, still claims the lives of citizens here in the United States every year. What’s interesting is not that there are still regular cases of the bubonic plague popping up around the American southwest, but that the reason this threat still exists is all because of San Francisco.

That’s because back in 1900, San Francisco was responsible for shipping in products from the far east; immediately after min-epidemics of this fierce disease had become a problem in places like China and Hawaii. And even though all goods and people had to pass a health inspection prior to coming ashore, local merchants were quick to lean on health officials to cut through the red tape as fast as possible.

It wasn’t until after the earthquake of 1906, when rats began taking over the city – that’s when the plague really started to become a problem in America. At that point, health officials simply could not get a grip on the disease due to it spreading at such a rapid and destructive pace – killing infected people within four days of being exposed it.

The bubonic plague is not a virus; it is a bacterial infection that lives in fleas and attacks a person’s lymphatic system. Once a person dies from the infection, the fleas leave the corpse and proceed to their next victim – and so on. Fortunately, this disease known as the “Great Pestilence” of the 14th century responds well to antibiotics. Still, it is worth mentioning that even in the world of modern medicine, the bubonic plague is still a killer - carrying a mortality rate of 11 percent.

Medical experts say that while the bubonic plague is very rare, there is no sign of it going away anytime in the near future. So, thanks a lot San Francisco; you owe us big time!