Throughout history, societies, technology and knowledge have evolved drastically. Diseases are no exception; they’ve evolved, too. The pandemics from centuries ago are not the same as the pandemics of today. While in the past diseases like leprosy and black plague ruled the world, today cardiovascular and pulmonary diseases are taking the gold medal. Heart disease is the leading cause of death in the United States and globally.

But these diseases may have something in common: Their prevention through life practices is and has always been the best medicine to eradicate them.



  • (an) illness of people, animals, plants, etc., caused by infection or failure of health rather than by an accident
  • something that is considered very bad in people or society 

Whether in a poetic or in a literal sense, we always perceive disease as something bad. After all, we “fall” ill.

The Pandemics of Today

Currently, cardiovascular diseases are the deadliest diseases in the world. Heart attacks are one of the most common forms that these diseases take. A heart attack can also be described as a myocardial infarction, standing for the death of tissue in the heart muscles. The coronary arteries that supply the heart itself and are injured during a myocardial infarction. Clogs can block these arteries, causing the heart’s blood supply to decrease instantly. The encircling tissues quickly enter ischemia, a state of oxygen deprivation. If not treated quickly, these heart tissues die and lose function irreversibly.

In order to treat heart attacks, or at least to diminish their side effects, we use anti-coagulants and as well as surgeries that help to open and unblock the blood vessels.

However, the most effective way of treating a heart attack is by preventing it in the first place.

Poor diet, a sedentary lifestyle, diabetes and smoking are underlying risk factors that must be addressed as a part of heart attack prevention. It’s no big news that our lifestyles are deeply connected to our risk for heart disease and our overall mortality risk.

But has it always been so? Could people in ancient times avoid the diseases of their day through lifestyle?

Learn about 5 habits that can save your heart here. More on preventing heart disease with the CDC here.

The Pandemics of Yesterday

Sure, exercise and proper nutrition are essential aspects of disease prevention across a range of human diseases. However, even the healthiest people in medieval times could not defend themselves against certain pandemics. For this “disease history lesson”, the Black Death is a must-have topic.

According to the Guinness Book of World Records, the pneumonic form of plague killed approximately 75 million people, being the most devastating pandemic of all time. Plague is an acute febrile illness transmitted by several animals but mostly fleas that carry Yersinia pestis, a rod-shaped bacteria that once inside a human organism multiplies in lymph nodes and in the respiratory tract, leading to lethal pulmonary lesions. 

Why is plague so devastating and how does it spread?

It was largely a lack of proper sanitary conditions and hygiene that lead to outbreaks of plague in the past. But the interesting (and gross) part is how plague-causing bacteria get into the human organism.

Humans are not the main hosts of Y. pestis, but rather incidental ones. The main vectors of plague are rat fleas, which end up transmitting the disease to humans out of true despair and thanks to a “blockage” phenomena.

[This might get gross!]

Fleas ingest infected blood with bacteria that somehow survive the digestive juices of these fleas. This first step is key for the massive transmission of plague. If fleas would digest and break down these bacteria, plague wouldn’t be that easily transmitted and wouldn’t have caused the huge pandemic we know from our history books.

Once in the flea, plague-causing bacteria multiply to the point of blocking what would be the flea’s digestive track, more specifically the proventriculus. The proventriculus is a structure in the flea’s gut that is essential for digestion and, as seen in the next picture, is blocked by bacteria. Consequently, the flea cannot digest any food and feels completely ravenous, constantly looking for a meal. (A very different phenomenon can cause humans to keep feeling hungry even when they have plenty of nutrients and fat stores available – it’s called leptin resistance!) 

Now we come to humans.

Flea 41 days after infection with P. pestis. Thrassis bacci, is one of the primary rodent flea vectors of plague to humans. Credit: CDC.
Flea 41 days after infection with P. pestis. Thrassis bacci, is one of the primary rodent flea vectors of plague to humans. Credit: CDC.

Fleas bite humans in a desperate act for nutrients. However, infected fleas find no relief from biting humans; instead, they end up regurgitating the dense amount of bacteria inside of their guts, right into their host human’s bloodstream. Now the host is infected with Y. pestis. Once in the human bloodstream, Y. pestis travels to the lymph nodes and the alveoli, multiplying densely and causing tissue death and inflammation, leading to serious pulmonary lesions and death.

Now vs Then: Curing Plague

In medieval times, curing plague was definitely a challenge. Without any drugs, people struggled to find a cure. But while plague was everywhere, many so-called “doctors” immediately took the opportunity to sell people herbs and potions, as if those were cures. As in many other diseases from medieval times, people also believed that the plague was a supernatural punishment. Consequently, they would perform rituals and prayers in desperate acts of survival, which, of course, didn’t work.

Modern medicine has all but eradicated plague. We now have antibiotics that can cure someone infected with plague bacteria. The antibiotic streptomycin is the most effective drug against Y. Pestis, especially if it involves the pulmonary system. Infected patients are also isolated and constantly monitored, since it’s still a frightening disease and Y. Pestis is still a dangerous specimen. Yet, it’s possible to properly manage plague with modern medicine. 

But perhaps the strongest weapon we have against plague is one of prevention, through proper sanitation and animal control in cities. Keeping flea-infested rats out of cities and homes, and keeping infected and ravenous fleas off of humans, has made plague a forgotten disease for history books (even though cases still do occur today).

Seeking Help from History

Even though we don’t have a cure for every disease that plagues us today, science shows us that our lifestyles and our life choices can truly change our disease risks. We can learn from history. Diseases have shaped the world. Whether through literature or science, illness will always follow humans and invade them. It is our duty as humans to fight that, but most importantly, to prevent it. 

Heart diseases are the current pandemic we must prevent, especially considering new evidence that we can pass heart disease risk to our children. The first and most important steps are getting regular exercise, eating balanced and plant-heavy diets, and quitting bad habits like smoking. Other preventative measures include regular visits to your primary care physician.

If we were living in the 16th century, we’d have plenty of excuses to die from one of the many pandemics of the day. But this is the 21st, and we can do better. Instead of keeping history lessons in the dark, let’s remember them and pair them with science and modern medicine. Our history may be sick, but prevention is key.