The world remains full of wonders, and there are many natural phenomena that are beyond what humankind can comprehend. As the planet changes over time, the organisms living in it also evolve. Unfortunately, viruses and bacteria also transform and mutate and continue to cause infectious diseases. In fact, they have been a constant companion of every generation for as long as history has ever recorded.
Amid the coronavirus (COVID-19) pandemic today, you might be wondering how it compares to the previous pandemics our world has seen so far.
Pandemics and Epidemics
Before we look into the biggest and worst pandemics in history, what is a pandemic anyway, and how is it different from an epidemic? These are two terms you hear the most on the news these days, and often, they are mistaken for one another.
Epidemic pertains to the event in which an infectious disease is actively spreading. It is a term that describes a problem that has gone out of control. A pandemic refers to an infectious disease that is currently affecting a whole country or the whole planet. In short, it is the term for the wider geographical spread of an epidemic.
Now, let's take a look at the five biggest pandemics in history.
HIV/AIDS (1981 to present)
Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) was first reported in 1981. It was caused by a virus that came from chimpanzees. Since then, HIV/AIDS has infected 75 million people and killed at least 32 million people worldwide. In 2018, it is estimated that 37.9 million people are still living with HIV/AIDS across the globe.
Plague of Justinian (541-542 AD)
The Plague of Justinian occurred in the 6th century and killed at least 30 million people across Asia, Europe, North Africa, and Arabia. The disease was due to the Yersinia pestis bacteria from rodents whose infected fleas carried the infection to humans. Many believe that this disease was what contributed greatly to the fall of the Roman Empire.
Spanish Flu (1918-1919)
The Spanish Flu is the worst influenza and the deadliest pandemic in recent history, which spread from 1918 to 1919 and killed about 50 million of the world population. The infection came from the H1N1 virus from pigs, which was novel at that time, just like COVID-19 is today.
With no vaccine to kill the virus, the control was mostly isolation, quarantine, social distancing, disinfecting, and good personal hygiene. However, these measures were applied unevenly, so the infections still spread uncontrollably.
Smallpox had been around since the third century, originating from Egypt. In 1520, however, the variola major virus started to spread. It killed 56 million Native Americans in the 16th-17th centuries, which was about 90 percent of their population. Smallpox was widespread in Europe, and in the 1800s, the disease killed around 400,000 people each year.
Smallpox claimed up to 300 million lives throughout its existence of 12,000 years. The World Health Organization (WHO) declared a smallpox eradication campaign across the world in 1959. Finally, in 1980, smallpox was eradicated-the first virus to be eliminated completely to date.
Black Death (1347-1351)
Black Death or Bubonic plague is the worst pandemic in history, which occurred between 1347 and 1351. It claimed the lives of around 200 million people. The infection came from rodents – the Yersinia pestis bacteria – which spread to humans through infected fleas. It was the same virus that caused the Justinian Plague but a different strain. The virus may have existed in Europe since 3000 B.C., but spread to other continents through trading ships. The outbreak in the 1340s slashed Europe's population by up to 50%.
Some of the viruses that caused the pandemics in the past may still be out there. Most of them are preventable, thanks to the vaccines that our scientists have developed to kill the virus and stop any outbreak. Improvements in the healthcare industry, including robust response measures, are also of great help in reducing the impact of an outbreak.
However, the risk of re-emergence is still there, so if we are not careful, we may see another outbreak. Or just like what we are going through right now, a new pandemic can break out.