Since the beginning of recorded human history, several diseases and illnesses have ravaged the populations. Some of these were weak and quickly passed with time. Others, however, had devastating effects that nearly wiped out the entire human civilization.

The last millennia has seen the outbreak of the worst pandemics in humankind's history, some of which returned to claim even more victims. Educate yourself with viruses and disease history with the five worst pandemics that terrorized humans in history.

Cocoliztli Epidemic

A viral form of hemorrhagic fever was responsible for causing the cocoliztli epidemic, whose name is translated from the Aztec language as a pest. It killed nearly 15 million citizens of Mexico and Central America. The disease surfaced at a time of extreme drought, causing even more panic among the population.

Scientists conducted a study that examined DNA gathered from the skeletons of individuals infected with a different species of Salmonella. The disease caused enteric fever, a type of fever that includes typhoid, which gives the victim a case of high fever, dehydration, and gastrointestinal issues.

Spanish Flu

In modern times, the flu is more of an annoyance than it is a deadly disease. But in the olden times, more specifically between 1918 and 1920, it took the lives of approximately 20 to 50 million people worldwide.

The deadly outbreak infected more than one-third of the entire human population. It was estimated to have a mortality rate of about 10-20 percent of the 500 million people who suffered. In the first 25 weeks, it took the lives of nearly 25 million individuals.

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HIV/AIDS

In 1976, the Democratic Republic of the Congo identified this disease and opened the world's eyes to a real global pandemic. Since the start of the outbreak in 1981, it took the lives of more than 36 million people in the region.

In modern times, however, around 31 to 35 million people live with HIV, the majority of which are in Sub-Saharan Africa, who have five percent of its population infected with the disease, totaling around 21 million individuals.

Plague of Justinian

In the capital of the Byzantine Empire, Constantinople, the Plague of Justinian, terrorized the population in 541 CE. Travelers from Egypt who crossed the Mediterranean Sea brought the disease. They brought grain that was feasted on by black rats, which fell victim to plague-ridden fleas that hitched a ride.

Spreading like wildfire across multiple countries, including Europe, Asia, North Africa, and Arabia, it took the lives of an estimated 30 to 50 million people, which, at the time, counted for nearly half of the world's population.

The Black Death

The deadliest and most infamous pandemic, the Bubonic Plague, or more commonly referred to as the Black Death, caused an astonishing 200 million deaths in only four short years. The plague ravaged Europe in 1347 and never really went away until it came back 800 years later for another round of killing.

The disease resulted in the creation of the system we now know as quarantine when an expert said that people at the time figured out the contagion had something to do with proximity. Officials monitored a port city and kept sailors who just arrived in isolation until it was guaranteed they were healthy.

Initially, the travelers would be held for 30 days, which they called trentino. However, as time went on, the isolation period was increased to 40 days, called a quarantino, which was later called quarantine.

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