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The Spookiest Sicknesses: The Hauntings of Past Pandemics ( Part 4)

As we approach the end of the Spookiest Sicknesses series, we will be covering our scariest story yet! This ghoulish story will strike fear into the hearts of all. This sickness is the pandemic of all pandemics and is known by many names, including THE BLACK DEATH.


The Black Death, also known as the Blue Sickness, the Great Mortality, La Pest (The Pestilence) or the Bubonic Plague, is history’s most deadly pandemic. Unlike COVID-19, smallpox, and the flu, the bubonic plague was not caused by a virus. It was caused by a type of bacteria known as Yersinia Pestis. Historically, it was believed that the plague spread as quickly as it did through rats carrying infected fleas in the 1300s. However, recent theories suggest that it might have also come from grains or lice carried from merchant ships arriving in Venice, Italy.

These ships were required to stay in the ports for 40 days once they arrived in Venice, Italy which people thought would be enough to stop the spread of any diseases brought from other countries. The word “quarantine” is based on the Italian term for this 40 day wait (quarantino). Regardless of how it came to be, it’s responsible for causing several pandemics in human history.



Like we mentioned in our last story, science and sicknesses are not pretty. They’re filled with things that make our skin crawl and can make us feel uncomfortable. The Bubonic Plague was a sickness that absolutely devastated several populations throughout of history. Let’s discuss how it became so severe. The plague, as mentioned earlier, was thought to be transmitted (or passed along) by infected fleas.

As these fleas were carried by rats into crowded areas where lots of people lived, the fleas would jump onto and bite unsuspecting humans, introducing the disease into the population. The Yersinia Pestis bacteria infected what’s essentially the throat of a flea, choking them as they tried to feed. As a result, the flea would throw up into its victim. This throw up is the key to infection because it is what carried the bacteria. Once a person was infected, the bacteria began to multiply. The bacteria traveled to the lymphatic system (a huge portion of the immune system) of the body and infected a lymph node. Once inside a person, the disease would rapidly multiply. The plague had a pretty short incubation period of just 2-8 days, meaning that after someone was exposed to the plague, symptoms show up a few days later. As the disease progresses, a few of the common symptoms (fever, headache, chills, fatigue) seen in the other sicknesses we've covered become more obvious.

But a key component to this disease (and the reason for its name) would start to show. Infected people would develop painful and swollen lymph nodes which are called buboes. These buboes could swell to become the size of an egg and, if untreated, would begin to turn black and fill with pus. Over the duration of the sickness, more of these buboes would form until the body would be overwhelmed with the disease, leading to death.



Since this disease happened well before the time of antibiotics, there was no good form of medicine or treatment. Rather, there was a focus on controlling the spread. This disease is the source for many of the public health measures that we can see to this day, specifically isolation and quarantines. The intense isolation of the infected individuals weakened the ability of the plague to spread. However, the damage was done. Throughout history, the plague has been responsible for at least six of the top twenty most deadly pandemics.

Ultimately, the Black Death holds the nightmare record of the most deadly pandemic of recorded history, an estimated 25 to 50 million lives being lost across Europe (around 33-66% of the population).

Sickness is a constant battle. Despite the odds and the horrifying nature of some of these pandemics, one thing is key: humans must find a way to take back control. Scientists make efforts to control the spread, fight infections, prevent the sicknesses, and keep people safe. But no matter what, history will always hold the tales of these truly Spooky Sicknesses.


Question: What causes the bubonic plague?

Question: What gave the bubonic plague its name?

Question: What is the incubation period of the bubonic plague

Question: How many people died during the Black Death

Question: What does the term "quarantine" come from?


Thank you to everyone who came along for this series! It's been so much fun to take a dive into the history and science of some of the biggest diseases of history. I encourage everyone to share the series and explore more of our blog!



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